Star Formation at High Redshift: The Confrontation Between Theory & Observations by Rafal Idzi A dissertation submitted to The Johns Hopkins University in conformity with the requirements for the degree of Doctor of Philosophy. Baltimore, Maryland January, 2007 c Rafal Idzi 2007 ! All rights reserved Abstract We investigate properties of Lyman-break galaxies by statistically comparing photometric observations with predictions derived from semi-analytic models based on the ΛCDM theory of hierarchical structure formation. We construct samples of U, B435 , and V775 -dropouts produced by GOODS, and complement the ACS optical B435 , V606 , i775 , and z850 data with the VLT ISAAC J, H, and Ks and IRAC 3.6, 4.5, 5.8, and 8.0 observations. We produce model dropout galaxies derived from semi-analytic model runs, where parameters controlling star formation and dust content are varied. We then construct model density functions and convolve them with observational scatter derived from Monte-Carlo simulations. We find the best-fit models by computing likelihoods using the data and model dropouts and the UV-continuum and Balmer-break color-magnitude diagnostics. We find that we cannot discern among models with varying starburst efficiencies due to data limitations. However, we do favor models with enhanced quiescent star formation. Our best-fit models rule out any strong dependence of quiescent star formation on circular velocities. We also favor dusty models. Using the best-fit models we present predictions for the stellar ii masses, SFRs, and ages of the z ∼ 3, z ∼ 4, and z ∼ 5 Lyman-break samples. We find that even though the current optical surveys are effective at selecting UV-bright, massive galaxies, they fail to select most of the stellar mass, which remains hidden in UV-faint and moderately massive galaxies. Our best-fit models predict a ∼ 70% mass build-up between the z ∼ 4 and z ∼ 3 epochs for UV rest-frame L∗ galaxies, and a smaller, ∼ 50%, build-up between the z ∼ 5 and z ∼ 4 epochs. This implies an on-going process of quite active stellar-mass assembly between the z ∼ 5 epoch and the z ∼ 3 epoch. Furthermore, for the z ∼ 3 sample, the stellar masses range from 108 to 1010 M" , roughly 1.5 orders of magnitude less than the stellar masses of the present day L∗ spirals and ellipticals – this indicates that the z ∼ 3 Lyman-break galaxies are not the fully assembled progenitors of the present-day L > L∗ galaxies. Finally, we find that quite a few of the z ∼ 5 galaxies have stellar masses of > 1010 M" , and that the median age of the z ∼ 5 population is 240 Myrs. This points to an already active star formation well before the z ∼ 5 epoch. Advisers: Dr. Henry Ferguson and Professor Timothy Heckman iii Acknowledgements I would like to express my sincerest thanks to my adviser Harry Ferguson. I had the pleasure to work with Harry for the past four years, and quite honestly I cannot fathom working with anyone else on my thesis. Thanks a bunch Harry for your support and especially for your patience. I would also like to thank all of the other, present and former, GOODS members who have been instrumental in helping me conduct and finish my work. Special thanks go to Rachel Somerville, Mark Dickinson, Mauro Giavalisco, Vicky Laidler, and Norman Grogin for providing help and support when I needed it. I would also like to thank Professor Timothy Heckman, who acted as my official faculty adviser since my third year here at Johns Hopkins. I’m grateful for his advice and support over the years, as well all of the useful Astronomy I’ve learned in his classes as a second and third year student. I want to thank all of my fellow grad students who have provided so much psychological support over all of these years, especially Soo who has been my office mate for the past two years, and thus had to put up with me during some of the most trying times – thanks Soo! I also greatly appreciate the help I have received over the years from the iv JHU Physics and Astronomy administrative office (especially Janet Krupsaw, Pam Carmen, Carm King, and Connie Fliegel) and from Patty Reeves at Space Telescope. Finally, I’d like to take this opportunity to thank my wife for supporting me with my academic aspirations. I know it wasn’t always easy for her and I want her to know that I appreciate her loving support. I would also like to thank the rest of my family without whom I wouldn’t accomplish any of this. Special thanks to my son, Lars, who brought so much joy into my life, that all by himself he brightened every day, most especially those difficult days. Thanks to all of you v Contents Abstract ii Acknowledgements iv List of Tables viii List of Figures x 1 Motivation 1 2 Hierarchical Models of Galaxy Formation 2.1 Historical Overview . . . . . . . . . . . . . 2.2 Semi-Analytic Models – Ingredients . . . . 2.2.1 Merger Trees . . . . . . . . . . . . 2.2.2 Gas Cooling . . . . . . . . . . . . . 2.2.3 Mergers . . . . . . . . . . . . . . . 2.2.4 Merger-Driven Morphology . . . . 2.2.5 Merger-Induced Star Formation . . 2.2.6 Quiescent Star Formation . . . . . 2.2.7 Supernovae Feedback . . . . . . . . 2.2.8 Chemical Evolution . . . . . . . . 2.2.9 Stellar Population Synthesis . . . . 2.2.10 Dust Extinction . . . . . . . . . . 2.3 Fiducial Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6 8 8 10 14 16 16 21 24 27 27 29 31 3 Observational Data 3.1 Introduction to GOODS . . . . 3.2 HST - ACS . . . . . . . . . . . 3.3 ESO VLT - ISAAC . . . . . . . 3.4 Spitzer - IRAC . . . . . . . . . 3.5 Ancillary Data . . . . . . . . . 3.5.1 CTIO 4m - MOSAIC U 3.5.2 ESO MPI 2.2–m - WFI 3.5.3 ESO NTT - SOFI . . . 3.6 Photometric Catalogs . . . . . 3.6.1 SExtractor Catalogs . . 3.6.2 TFIT Catalogs . . . . . 3.7 Galaxy Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 33 37 40 42 43 43 44 45 45 45 47 49 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 50 53 53 57 4 Model Exploration, Parameter Choices, & Diagnostics 4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Model Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1 Dust Parameters . . . . . . . . . . . . . . . . . . . . . . . 4.2.2 Quiescent & Merger-Induced Star Formation Parameters 4.2.3 Supernovae Feedback . . . . . . . . . . . . . . . . . . . . 4.3 Final Model Parameters & Model Run Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 74 75 75 77 80 81 3.8 3.7.1 Lyman Break Galaxies . . . . . . . 3.7.2 Color Selection Criteria & Samples Template-Fitting Software Package . . . . 3.8.1 TFIT Overview . . . . . . . . . . . 3.8.2 TFIT Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Simulations and Observational Scatter 100 5.1 ACS Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 5.2 ACS–IRAC TFIT Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 6 Methodology 6.1 Overview . . . . . . . 6.2 Data . . . . . . . . . . 6.3 Models . . . . . . . . . 6.4 Observational Scatter 6.5 Likelihood Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 118 119 120 122 123 7 Results & Discussion 7.1 Best-fit Model(s) . . . . . . . . . . . . . . . . . 7.2 Parameter Fits – Implications . . . . . . . . . . 7.2.1 Burst-driven Star Formation Parameters 7.2.2 Quiescent Star Formation Parameters . 7.2.3 Dust Parameter . . . . . . . . . . . . . . 7.3 Properties of High-Redshift Galaxies . . . . . . 7.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 135 138 138 139 140 141 144 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography 166 A Spherical Collapse in a General Cosmology 183 B Table of Model Runs 188 C Tables of Lyman-Break Galaxies 203 vii List of Tables 2.1 Fiducial Model Parameter Choices . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3.1 3.2 Instrumental Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Data Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 38 4.1 4.2 4.3 Grid of Parameter Choices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Final Parameter Choices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diagnostic Choices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 82 83 6.1 Diagnostic Limits & Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 7.1 7.2 7.3 Best-fit Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Models Within the 68% (in bold) & 99.9% Confidence Intervals. . . . . . . . . . . . 136 Best-fit Models (Refit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 B.1 B.1 B.1 B.1 B.1 B.1 B.1 B.1 B.1 B.1 B.1 B.1 B.1 B.1 List List List List List List List List List List List List List List C.1 C.1 C.1 C.1 C.1 C.1 C.1 C.1 U-dropout U-dropout U-dropout U-dropout U-dropout U-dropout U-dropout U-dropout of of of of of of of of of of of of of of All All All All All All All All All All All All All All Models Models Models Models Models Models Models Models Models Models Models Models Models Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lyman-break Lyman-break Lyman-break Lyman-break Lyman-break Lyman-break Lyman-break Lyman-break . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sample Sample Sample Sample Sample Sample Sample Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 190 191 192 193 194 195 196 197 198 199 200 201 202 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 205 206 207 208 209 210 211 viii C.1 C.1 C.1 C.1 C.1 C.1 C.1 C.1 C.1 C.1 C.1 C.2 C.2 C.2 C.2 C.2 C.2 C.2 C.2 C.2 C.3 C.3 U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample U-dropout Lyman-break Sample B-dropout Lyman-break Sample B-dropout Lyman-break Sample B-dropout Lyman-break Sample B-dropout Lyman-break Sample B-dropout Lyman-break Sample B-dropout Lyman-break Sample B-dropout Lyman-break Sample B-dropout Lyman-break Sample B-dropout Lyman-break Sample V-dropout Lyman-break Sample V-dropout Lyman-break Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 List of Figures 2.1 2.2 2.3 2.4 2.5 Extended Press-Schechter Mass Function . . . . . . . Cooling Radius . . . . . . . . . . . . . . . . . . . . . . Efficiency of Merger-Triggered Star Formation . . . . . Star formation Rate as a Function of Circular Velocity Sample Star Formation Histories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 12 20 23 25 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 Exposure map of the GOODS CDF-S Observations. . . . . . . . Target Areas of All CDF-S Data Sets . . . . . . . . . . . . . . . . IRAC Epoch Exposure Layout . . . . . . . . . . . . . . . . . . . ACS z850 Completeness Limits . . . . . . . . . . . . . . . . . . . Epoch 1 vs Epoch 2 Normalized Flux Comparison . . . . . . . . U-dropout Sample Colors . . . . . . . . . . . . . . . . . . . . . . U-dropout Sample Colors . . . . . . . . . . . . . . . . . . . . . . B-dropout Sample Colors . . . . . . . . . . . . . . . . . . . . . . B-dropout Sample Colors . . . . . . . . . . . . . . . . . . . . . . V-dropout Sample Colors . . . . . . . . . . . . . . . . . . . . . . V-dropout Sample Colors . . . . . . . . . . . . . . . . . . . . . . B-dropout Color Selection for Data and Models . . . . . . . . . . TFIT Flow Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . TFIT Simulated and Residual Images . . . . . . . . . . . . . . . TFIT vs SExtractor Errors as a Function of Source Separation . TFIT Residuals for Pre-Shift vs Post-Shift Runs . . . . . . . . . TFIT Photometry for Pre-Shift vs Post-Shift Runs - Fluxes . . . TFIT Photometry for Pre-Shift vs Post-Shift Runs - Magnitudes TFIT vs Isophotal Flux Test for Isolated Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 37 42 46 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 Power-Law Dust Variation for B-dropouts with a Low τdust, 0 Power-Law Dust Variation for B-dropouts with a High τdust, 0 Power-Law Dust Variation for B-dropouts with a Low βdust . Power-Law Dust Variation for B-dropouts with a High βdust . Charlot-Fall Dust Variation for B-dropouts with Low Dust . Charlot-Fall Dust Variation for B-dropouts with High Dust . Charlot-Fall Dust Variation for B-dropouts with a Low ndust Charlot-Fall Dust Variation for B-dropouts with a High ndust High Star Formation for B-dropouts . . . . . . . . . . . . . . Low Star Formation for B-dropouts . . . . . . . . . . . . . . . High vs Low Star Formation Histories - z850 < 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 84 85 86 87 88 89 90 91 92 93 x . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.12 4.13 4.14 4.15 4.16 4.17 High vs Low Star Formation Histories - All Galaxies . . High vs Low Star Formation Histories - Smoothed SFR Martin-Heckman SNae Feedback for B-dropouts . . . . Power-Law SNae Feedback for B-dropouts . . . . . . . . Sample Balmer-break Colors for U-dropouts . . . . . . . Sample UV-continuum Colors for U-dropouts . . . . . . . . . . . . . . . . . . . . . . . . 94 95 96 97 98 99 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 5.14 5.15 5.16 5.17 Redshift Distributions for the Simulated B-dropouts . . . . . Redshift Distributions for the Fiducial Model B-dropouts . . Input i775 - z850 Colors for the Simulated B-dropouts . . . . . Output i775 - z850 Colors for the Simulated B-dropouts . . . . Input V606 - i775 Colors for the Simulated B-dropouts . . . . Output V606 - i775 Colors for the Simulated B-dropouts . . . E(B-V) Distribution for the Simulated B-dropouts . . . . . . SExtractor-TFIT Cumulative Recovery Rates in the CDFS vs IRAC 3.6 PSF . . . . . . . . . . . . . . . . . . . . . . . . . . Simulated and Real V606 & IRAC 3.6 Mosaics . . . . . . . . . Input Magnitude Distributions . . . . . . . . . . . . . . . . . Intput V606 - IRAC 3.6 Colors for All Galaxies . . . . . . . . Output V606 - IRAC 3.6 Colors for All Galaxies . . . . . . . . IRAC 4.5 PSF . . . . . . . . . . . . . . . . . . . . . . . . . . Simulated and Real z850 & IRAC 4.5 Mosaics . . . . . . . . . Input z850 - IRAC 4.5 Colors for All Galaxies . . . . . . . . . Output z850 - IRAC 4.5 Colors for All Galaxies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Source Separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 Simulation Machinery Flow Chart . . . . . . . . . . . . . . . . . . . . . . . . Sample U-dropout Model Density Function Probing the UV-continuum . . . Sample B-dropout Model Density Function Probing the UV-continuum . . . Sample U-dropout Model Density Function Probing the Balmer-break Colors Sample B-dropout Model Density Function Probing the Balmer-break Colors V606 - i775 vs i775 Scatter Density Functions . . . . . . . . . . . . . . . . . . . i775 - z850 vs z850 Scatter Density Functions . . . . . . . . . . . . . . . . . . . V606 - IRAC 3.6 vs V606 Scatter Density Functions . . . . . . . . . . . . . . . z850 - IRAC 4.5 vs z850 Scatter Density Functions . . . . . . . . . . . . . . . . Pre vs Post Observational Scatter . . . . . . . . . . . . . . . . . . . . . . . . . Applied Scatter Function - B-dropout UV-continuum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 125 126 127 128 129 130 131 132 133 134 Best-fit Model Density Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Random Draws from the Best-fit Model Density Function - U-dropouts, UV Colors . Random Draws from the Best-fit Model Density Function - U-dropouts, Balmer-break Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Random Draws from the Best-fit Model Density Function - B-dropouts, UV Colors . 7.5 Random Draws from the Best-fit Model Density Function - B-dropouts, Balmer-break Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Random Draws from the Best-fit Model Density Function - B-dropouts, Balmer-break Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 Stellar Masses for Best-fit U-dropouts . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8 Stellar Masses for Best-fit B-dropouts . . . . . . . . . . . . . . . . . . . . . . . . . . 7.9 Stellar Masses for Best-fit V-dropouts . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10 Stellar Mass Distribution for Best-fit U-dropouts . . . . . . . . . . . . . . . . . . . . 7.11 Stellar Mass Distribution for Best-fit B-dropouts . . . . . . . . . . . . . . . . . . . . 7.12 Stellar Mass Distribution for Best-fit V-dropouts . . . . . . . . . . . . . . . . . . . . 148 149 7.1 7.2 7.3 xi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 151 152 153 154 155 156 157 158 159 7.13 7.14 7.15 7.16 7.17 7.18 Stellar-Mass Weighted Age for Best-fit U-dropouts . . . Stellar-Mass Weighted Age for Best-fit B-dropouts . . . Stellar-Mass Weighted Age for Best-fit V-dropouts . . . Smoothed Star Formation Rates for Best-fit U-dropouts Smoothed Star Formation Rates for Best-fit B-dropouts Smoothed Star Formation Rates for Best-fit V-dropouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 161 162 163 164 165 A.1 Halo Mass and Virial Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 xii In memory of Jan Idzi xiii Chapter 1 Motivation Ever since Edwin Hubble (1889-1953) confirmed the nature of Kant’s ’island universes’ by detecting Cepheid variable stars in M31 using the 100-inch telescope atop Mount Wilson, the scientific research into the nature of galaxies has flourished. Over the past several decades scores of researchers have scrutinized countless galaxies in order to learn more about them. The knowledge gained over these past few decades stems both from deeper and more comprehensive observations of galaxies as well as from a slew of theoretical galaxy formation and evolution models based on analytical, numerical, as we as semi-analytic methods. The progress has been tremendously helped by the more recent rapid advances in our understanding of the cosmological properties of the universe and the evolution of the stellar populations that make up the individual galaxies. Without a doubt, our contemporary understanding of galaxy formation and evolution far surpasses the knowledge gained in those early days, however, despite our vastly improved knowledge we are still largely ignorant of how galaxies form and evolve. It has been clear for some time that the results from the theoretical galaxy formation models, while adept at replicating some of the observational data, have many problems when it comes to reconciling all model predictions with the observational evidence. One of the most ill-understood processes in galaxy formation and evolution is the stellar mass assembly, or in other words, the star formation history. It is still not clear when, at what rate, and 1 by which means galaxies accrue their stellar mass. Given the complicated non-linear nature of the underlying physics it is difficult to determine which mechanisms play a dominant role in the process of star formation. This complicated process can either be solved by trying to determine the precise nature of the physics underlying these phenomenologies, or by employing approximations which can then be fine-tuned and refined using the observational data. For the latter method, the need arises for powerful statistical techniques capable of comparing the observed data with an ensemble of models to determine which models work and which do not. Over the past several years a good deal of progress has been made towards understanding the nature of galaxy formation and evolution. However, these advances have been quite limited in their scope and as a result the problem of galaxy formation and evolution remains unsolved for the most part. This lack of good understanding has been partially due to the lack of exhaustive observational data, but also to the lack of sophisticated theoretical models. More importantly though, the biggest handicap has been the deficiency in robust analysis tools that have the ability to compare data and models in a quantitative manner. As stated, galaxy evolution is a complex problem that depends on a multitude of factors, many of which depend on one another and all of which evolve with time. For any individual galaxy, the star formation and mass assembly history (Ṁ∗ (t), M (t)) can be quite complicated. There are many factors that regulate galaxy’s star formation rate, including, radiative cooling via molecular and heavy element line transitions, energy feedback from supernovae, fresh gas infall rate, and merger induced shocks. In the standard paradigm of galaxy formation, galaxies grow through the accretion of smaller galaxies and gas infall from the surrounding medium. One can easily see how these various factors can greatly complicate matters and as a result make the study of galaxy evolution challenging. The understanding of galaxy evolution processes is further complicated by the intrinsic limitations of astronomical observations. The total masses of galaxies can be determined through rotation velocities or velocity dispersions via high resolution spectroscopy. However, this is observationally expensive and becomes impossible for distant galaxies. Often this is circumvented by assuming a galaxy’s mass to light ratio and 2 estimating a lower mass limit from galaxy’s total luminosity. A further difficulty is that we are unable to resolve individual stars for all but the closest galaxies. Because of this limitation we only observe the integrated light, which is dominated by the youngest stars causing only the most recent star formation episode to show through, while subduing the older, fainter, stellar populations. To date, galaxy evolution studies have mostly centered on comparing simple evolutionary models to one dimensional binned distributions of observable properties such as luminosity, redshift, color, and morphology. This type of analysis probes a very limited region of parameter space and there is no way to assign any confidence intervals to the best-fit parameters. Furthermore, if one has access to multiple data sets, this type of analysis precludes any quantitative comparison among the data, and only qualitative conclusions can be drawn. Obviously, this severely curtails the use of observational data. Alternatively, some studies have fit simple parameterized star formation histories to the photometry of individual galaxies, attempting thereby to derive stellar masses, ages, dust content, etc., but imposing no requirement of consistency between different slices of redshift. In order to circumvent the limitations of such previous efforts, we decided to take a different approach. First, instead of using simple evolutionary models, we chose a semi-analytic hierarchical model, where model universes are produced using randomly generated merger trees, and various galaxy properties are generated by a set of physically-based scaling laws that control such processes as gas cooling, star formation, chemical enrichment, various feedback processes, etc. This provides us with a far more realistic representation of model galaxies than the representations afforded by simple evolutionary models. Moreover, the complex feedback processes provide us with a list of parameters that can be directly adjusted to generate a sets of different models in a manner that is computationally efficient compared to full N-body hydrodynamic simulations and probably as accurate in its treatment of stellar formation. Our second change, is to use the a the most comprehensive data set on high-redshift galaxies to date – the Great Observatories Origins Deep Survey (GOODS) data set. This data set not only affords the depth necessary to explore high-redshift galaxies, but also provides a large enough area coverage so as to be statistically meaningful. Finally, we choose a 3 more robust methodology to study the models and the data. Briefly, we use the photometric information from the models to construct finely gridded model density functions in color-magnitude space that are then smoothed with observational scatter taken from Monte-Carlo simulations and then we compute the likelihoods of the model using the data points from our Lyman-break samples. We repeat this process for a set of models produced from a set of parameters that control such physics as star-formation and dust content. The computed likelihoods, taken together with confidence intervals created through post-analysis Monte-Carlo simulations, give us the relative probability of the models, indicating which models are favored and which are ruled out. This method affords us with a more robust approach of contrasting models with data as it allows us to assign quantitative measures and allows us to test the models against multiple Lyman-break samples (z ∼ 3 and 4) across multiple color-magnitude diagnostic combinations. It also takes explicit account of observational measurement error, biases, and incompleteness in a straightforward way. In §2 we review the underpinnings of the semi-analytic model used in this project. We also state some of the parameter choices that we make. In §3 we go over the data used in this project. We describe how that data were obtained and what are the characteristics of that data. We go into catalog creation and selection of the galaxy samples. We conclude with a description of the software package used to create the catalogs. In §4, we continue our discussion from §2, but here we wholly concentrate on the parameter selection process. That is, we go over how we chose the parameters for this analysis. We also describe how we chose the diagnostics that were used for the analysis. Finally, we explicitly state those diagnostics and our parameter choices. In §5 we review the Monte-Carlo data simulations that were performed to test the stability of our data catalogs and our Lyman-break samples. We also go over how those simulations were used to create simulated galaxy catalogs that were directly used in creation of the observational scatter functions that were used to process our model galaxies. In §6 we describe the methodology of our analysis. We carefully go over all of the steps of our analysis, listing all of the components used, and how those components were derived. Finally, in §7, we go over the results of our analysis and review the implications of our results on 4 the physical questions posed in our work. 5 Chapter 2 Hierarchical Models of Galaxy Formation 2.1 Historical Overview Recent theoretical advances and Wilkinson Microwave Anisotropy Probe (WMAP) results have promoted the ΛCDM hierarchical structure formation paradigm to the status of the fiducial framework for the formation and evolution of galaxies. The various cosmological parameters comprising this framework have been fine-tuned over the past several years with the help of the WMAP data (Spergel et al 2003). While cosmological parameters have been well established, the physics that drives galaxy formation and evolution is less certain. Many researchers have used either N-body simulations or Semi-Analytic models to simulate the processes that are thought to be important. While N-body simulations provide very detailed modeling of such characteristics as gas dynamics, they still have great difficulty reproducing the observed properties of galaxies in detail (Steinmetz (1997)). N-body simulations also suffer a huge dynamic range problem. It is impossible with today’s technology to cover the requisite range of densities, from those associated with molecular clouds to 6 those associated with intergalactic space. It is also quite apparent that there must be additional physics that needs to be included in order to obtain realistic galaxies in the ΛCDM framework. It is likely that many of these processes (e.g. cooling, star formation, supernova feedback, etc.) form a complicated non-linear feedback loop. It becomes computationally prohibitative to include realistic physics over the required dynamic range in N-body simulations of significant volume. In fact, by their design alone, N-body simulations are highly processor intensive, and thus do not lend themselves to a comprehensive and detailed study of the nonlinear effects driving galaxy evolution. Nevertheless N-body simulations that include hydrodynamics, shocks, star formation, and feedback (Nagamine et al. 2004; Springel 2005; Navarro et al. 1996) continue to improve. Semi-analytic models (SAMs) of galaxy formation are embedded within the framework of a ΛCDM-like initial power spectrum and the theory of the growth and collapse of fluctuations through gravitational instability. The models include a simplified physical treatment of gas cooling, star formation, supernova feedback, dust extinction, and galaxy merging. The approach is MonteCarlo based, which allows us to study individual objects or global quantities. Many realizations can be run in a moderate amount of time on a workstation. Therefore, this approach is an efficient way of exploring the large parameter space occupied by the unknowns associated with star formation, supernova feedback, the stellar initial mass function, metallicity yield, dust extinction, etc. Besides the computational efficiency, these models provide an important level of understanding that would be difficult to achieve by running an N-body simulation. Semi-analytic models were first developed by Kauffmann et al. (1993) and Cole et al. (1994). The model used here (Somerville et al. 1999) is similar in spirit and adopts many of the fundamentals, however, it differs significantly from those early models, especially in its current form. All of these models and the underlying physical assumptions have evolved significantly since the mid-90’s and many of the deficiencies of the early models have been addressed. In the next few sections we describe the workings of the Somerville et al. (1999) model, including the treatment of merger trees, gas dynamics, mergers, star formation, feedback, dust extinction, and more. Due to the intrinsic complexity of semi-analytic models, we 7 cannot cover all the details of the model. Much of the background is covered by Somerville & Primack (1999) and Somerville, Primack, & Faber (2001). However, for completeness, we cover the most important aspects of the model in sufficient detail and include description of the model assumptions and algorithms that have changed since the earlier implementations. We adopt the following cosmological parameters for our ΛCDM treatment: (ΩΛ = 0.7, Ωm = 0.3, h = H0 /100 km s−1 Mpc−1 = 0.7). This set of cosmological parameters will be used throughout this project. 2.2 2.2.1 Semi-Analytic Models – Ingredients Merger Trees Semi-analytic models make use of the extended Press-Schechter formalism (Press & Schechter 1974; Bower 1991; Bond et al. 1991; Lacey & Cole 1993) to obtain the probability that a halo of a given mass m0 at a given redshift z0 has a progenitor of mass m1 at some larger redshift z1 . The merging histories of the dark matter halos are then assembled via Monte-Carlo realizations (Kauffmann & White 1993; Cole 1991; Somerville & Kolatt 1998). The relative agreement between this type of formalism vis-a-vis pure N-body simulations is quite good, although it has been well documented that the Press-Schechter theory over-predicts the number of halos by about a factor of two (Tormen 1998; Somerville et al. 1998; Somerville & Kolatt 1998). In addition, the Press-Schechter model predicts stronger evolution of the halo mass function as a function of redshift Gross (1997); Somerville et al. (1998). These problems cannot be easily solved. However, a solution was proposed by Sheth & Tormen (1999), which proposes a corrective term to the Press-Schechter formalism. The correction, which is the mass function from the Sheth-Tormen model divided by the standard Press-Schechter mass function, is shown in Fig. 2.1, and it improves the agreement between PressSchechter derived models and N-body simulations. Despite the above disagreements between the two varieties of simulations, the overall properties of progenitors within a halo of a given mass are 8 Figure 2.1 The mass function from the improved Press-Schechter model proposed by Sheth & Tormen (1999) divided by the standard Press-Schechter mass function. This correction factor is a function of redshift as well as halo mass, and here is shown for z = 0. (This figure was reproduced, with permission, from Somerville & Primack (1999)). 9 very similar. As long as the error in the Press-Schechter formalism is corrected for, the semi-analytic implementation serves as a reliable framework for studying hierarchical galaxy formation. The semi-analytic model used in this work implements the merger-tree method of Somerville & Kolatt (1998). In it, the merging history of a dark-matter halo is constructed by sampling the paths of individual particle trajectories using the excursion set formalism (Bond et al. 1991; Lacey & Cole 1993). This method does not require a grid in mass or redshift, nor does it require the merger events to be binary. Monte-Carlo techniques are used to randomly pick the redshifts and masses associated with the halo mergers. The only criterion is that the overall distribution satisfies the averages predicted by the extended Press-Schechter theory. Each realization then is a particular merger tree history. This forms the core of the code and it is the most vital stochastic component in the models. Additional constraints revolve around making the tree finite. This requires a minimum mass mmin below which merger histories are not traced. Instead the mass that falls below this limit is accreted as a diffuse component. In our model runs, we set this mass limit to a halo with a circular velocity of 40 km s−1 at a relevant redshift. This limit seems reasonable since halos smaller than the limit are unlikely to form due to the photoionization of gas and the consequential inability to cool (Weinberg et al. 1997; Forcado-Miro 1997). We set an upper limit of 1200 km s−1 for all of our model runs in order to make processing time manageable. 2.2.2 Gas Cooling The next important component in the semi-analytic approach is the treatment of gas cool- ing. When a halo collapses or undergoes a merger with a larger halo, the associated gas is assumed to be shock-heated to the virial temperature of the halo. This gas then radiates energy and as consequently cools. The cooling rate typically depends on a variety of factors such as density, metallicity, and temperature of the gas. The treatment of gas cooling in this semi-analytic model follows a scheme similar to the one used by White & Frenk (1991). A newly formed, dark matter tracing, halo (residing at top of the tree) contains pristine shock heated hot gas (at virial T ). Radiative 10 cooling then leads to energy loss. The rate of specific energy loss is given by the cooling function Λ(T ). The expression giving the critical density for gas cooling on a given time scale τcool is ρcool = 3 µmp kB T 2 χ2e τcool Λ(T ) (2.1) where µmp is the mean molecular weight of the gas and χe ≡ ne /ntot is the number of electrons per particle. If we assume that the gas is fully ionized and has a helium fraction by mass of Y = 0.25 then we have ρcool = 3.52 × 107 kB T , τcool Λ23 (T ) (2.2) where kB T is in degrees Kelvin, τcool is in Gyr, and Λ23 (T ) ≡ Λ(T )/(10−23 ergs s−1 cm3 ). The 2 virial temperature is approximated as kB T = 71.8σvir , where σvir is the virial velocity dispersion of the halo. The cooling radius can now be obtained by inverting the above equation and assuming a gas density profile ρg(r) . The cooling radius is defined as the radius within which the gas has had time to cool within a given time-scale τcool (see Fig. 2.2). If we assume a singular isothermal sphere for the gas profile we obtain rcool = ! ρ0 ρcool "1/2 where ρ0 = fhot Vc2 /(4πG), fhot is the hot gas fraction in the cooling front and Vc = (2.3) √ 2σvir is the circular velocity of the halo. We adopt the cooling function of Sutherland & Dopita (1993) and model value of the hot gas metallicity, and use the metallicity-dependent radiative cooling curves tabulated by Sutherland & Dopita (1993) to compute cooling for different metallicities. The time interval between halo mergers is divided into small time-steps. For each time-step ∆t, the cooling radius increases by an amount ∆r. In addition, we assume that the mass of gas that cools in this time-step is given by 11 Figure 2.2 Cooling radius of halos as a function of circular velocity. The straight diagonal line shows the virial radius, which the cooling radius may not exceed. The curved lines show the cooling radius predicted by the static halo cooling model (see text), assuming that the hot gas has primordial, 0.3 solar, or solar metallicity. Open circles show the application of the static halo model within the merger trees, and crosses show the dynamic halo model (see text), assuming a fixed metallicity of 0.3 solar. Earlier conversion of gas from the hot to cold phase and reheating of hot gas by halo mergers results in a lower cooling efficiency for large halos in the dynamic halo model. (This figure was reproduced, with permission, from Somerville & Primack (1999)). 12 2 dmcool = 4πrcool ρg (rcool )∆r (2.4) For small halos at high redshifts we assume that the cooling is limited by the accretion rate, since the amount of gas that can cool at any given time-bin cannot exceed the amount of hot gas contained within the halo’s virial radius. The mass of accreted hot gas between halo mergers is given by fbar macc (2.5) where fbar ≡ Ωb /Ω0 is the universal baryon fraction. We also assume that the mass accretion rate is constant over the time interval in between mergers (this is expected from the spherical collapse model – see Appendix A – where we reproduce the arguments from Somerville & Primack (1999)). The gas that cools falls onto the disk at a rate given by the sound speed of the gas cs = (5kB T /3µmp )1/2 ∼ 1.3σv (2.6) where σv is the 1-D velocity dispersion of the halo, and cs is roughly the dynamical velocity of the halo. This behavior of cooling gas infall is supported by the N-body hydrodynamical simulations of Evrard et al. (1996). For halos at the top-level (all progenitors less massive than the minimal mass), the fraction of hot gas fhot is set to the universal baryon fraction fbar , and the cooling time τcool is defined as the time elapsed since the initial collapse of the halo. In halo mergers, if the mass of the largest progenitor m1 comprises more than a fraction freheat of the post-merger mass m0 , the cooling radius and time of the new halo are set to those of the largest progenitor. The gas fraction in the cooling front is fhot = mhot /mtot (> rcool ) (2.7) where mhot is the entire mass of the hot gas from all the progenitors, and mtot (r > rcool ) is the total 13 mass contained in between the cooling and the virial radii (for an isothermal profile). In contrast, if m1 /m0 < freheat then the hot gas within all the progenitors is heated to the virial temperature of the new halo, and the cooling radius and time values are reset to zero. The gas fraction in the cooling front is then fhot = mhot /m0 (2.8) In the static halo cooling model we always assume that fhot = fbar and that τcool equals to the age of the Universe at any given time. Furthermore, no reheating of the gas occurs after any halo merger. In addition, we modify the literal static cooling model by requiring the cooling rate not to exceed the available supply of hot gas, or to exceed the sound speed constraint. In Figure. 2.2 we show the cooling radius in the literal and modified static cooling models. The consequence of this modeling is that for small halos, the cooling is ultimately limited by the available collapsed gas supply. For large halos, cooling is suppressed in the dynamic halo model in contrast to the case of a static halo model. This is due to the lower values of fhot and the ongoing reheating by halo mergers. 2.2.3 Mergers The treatment of mergers is a complex process and we encourage the reader to refer to Somerville & Primack (1999) and Somerville, Primack, & Faber (2001) for a detailed description. Here we present a brief overview. Once halos merge, the galaxies within them remain distinct for some time. The central galaxy of the largest progenitor halo is set as the central galaxy of the merged dark matter halo. All the other galaxies become satellites. The satellites of the largest progenitor remain undisturbed and the central galaxies of other progenitors are placed at a distance fmrg rvir from the central galaxy, where fmrg is a free parameter and rvir is the virial radius of the new parent halo. The satellites from the smaller progenitors are scattered randomly in the new halo, preserving their relative distance to the new central galaxy. All the satellite galaxies then fall in toward the core galaxy due to dynamical friction. The evolving distance of a satellite galaxy is given by, 14 rfric drfric Gmsat = −0.428f (') ln Λ dt Vc (2.9) (Binney & Tremaine 1987; Navarro et al. 1995). where msat is the combined mass of the satellite’s gas, stars, and dark matter halo, and Vc is the circular velocity of the parent halo. ln Λ is the Coulomb logarithm, which is approximated as ln Λ ≈ ln(1 + m2h /m2sat ), where mh is the mass of the parent halo. The value of ' (circularity parameter) is defined as the ratio of the angular momentum of the satellite to that of a circular orbit with the same energy: ' = J/Jc (E). For each satellite, ' is drawn from a uniform distribution from 0.02 to unity. As the satellite galaxy’s orbit decays, its dark matter halo is stripped by the parent halo. The tidal radius rt of the satellite halo, which is taken to be the spatial point where the satellite halo density equals the density of the background halo, is given by, ρsat (rt ) = ρhalo (rfric ) (2.10) The mass of the satellite halo is then taken to be the mass contained within the tidal radius. In each case, the halos are assumed to be isothermal spheres (ρ ∝ r−2 ). In addition to the above process we can also have mergers or interactions between satellite galaxies. The time-scale for this process is given by a mean free path argument, τcoll ∼ 1 n̄σv (2.11) where n̄ is the mean density of galaxies, σ is the effective cross section for a single galaxy, and v is a characteristic velocity. N-body simulations by Makino & Hut (1997) reveal that this simple argument results in reliable merger rates. The collision time-scale used in our semi-analytic model is given by an expression adopted from the N-body work, τcoll = 500 N −2 ! rhalo Mpc "3 ! 15 rgal 0.12 Mpc "−2 # $−4 # σ $3 σgal halo Gyr. 100 km s−1 300 km s−1 (2.12) where rhalo is the virial radius of the parent halo, rgal is the tidal radius of satellite’s dark matter halo, σgal and σhalo are the internal 1-D velocity dispersions of the satellite and the parent halo, respectively. The probability then that a galaxy will merge in a given time step is Pmrg = ∆t/tcoll . For the post-merger sub-halo we assign a new velocity dispersion by assuming that energy is conserved in the collision and the product satisfies the virial relation. The above expressions describe all of the merging events in our models. 2.2.4 Merger-Driven Morphology We adopt a free parameter, fbulge , which determines whether a galaxy merger leads to formation of a bulge component. If the baryonic mass ratio of the merging smaller galaxy to the merging bigger galaxy is greater than fbulge , then all the stars from both galaxies are put into the bulge and the disk is destroyed. If the ratio is smaller then the stars from the smaller galaxy are deposited into the disk of the bigger galaxy. The cold gas of both galaxies are combined, and if additional cooling takes place this may lead to the formation of a new disk. The bulge-to-disk ratio of each galaxy can then be used to assign a morphological classification. In this project we do not concern ourselves with morphological types. It is sufficient to state that the classification scheme used in this model leads to morphological properties that are in agreement with a variety of observations (see Somerville, Primack, & Faber (2001) for details). In all of our simulations we set the fbulge parameter to a value of one third. 2.2.5 Merger-Induced Star Formation There is considerable observational and theoretical evidence that mergers and interactions between galaxies trigger enhanced star formation. In our simulations we adopt a lower limit for the mass threshold that will induce any sort of starburst (5 to 10%, Cox et al. (2005)). Once that threshold is met however, we assume that every galaxy-galaxy merger triggers a starburst. The 16 treatment of merger-triggered burst is based on a simple parameterization of the results of N-body simulations with gas dynamics. Initially, the semi-analytic model used in this work used results of Mihos & Hernquist (1994; 1996). The authors of that work simulated galaxy-galaxy mergers using a high resolution N-body/smoothed particle hydrodynamics code (TREESPH) with star formation modelled according to a Schmidt law (ρSF R ∝ ρngas with n = 1.5). Mihos & Hernquist (1996) found that 65-85% of the total gas supply (in both galaxies) was converted into stars over a time scale of 50-150 Myr. These results were for equal-mass mergers, or major mergers. In addition, they found that the results insensitive to morphology or the orbital geometry. In Mihos & Hernquist (1994) they studied the case of highly unequal-mass (minor) mergers (at 1:10 ratio). This scenario produced a non-axisymmetric mode generated by the accretion of the smaller galaxy. This mode caused majority of the gas to collapse into the core of the larger galaxy, which produced a strong starburst. The consumption of the gas was at 50% spent over 60 Myr. The major difference between the two types of mergers is that the latter depends strongly on the morphological properties of the galaxies. If there is a bulge, the bulge stabilizes the disk against strong radial gas flows, which results in weaker starbursts (5% of gas consumed). This behavior was observed for substantial bulges with bulge-to-disk mass ratio of one third or more. Each merger is then classified as either major or minor depending on whether the ratio of the smaller to the larger of the galaxies’ baryonic masses is greater than or less than the value of the bulge-to-total mass ratio (fbulge ∼ 0.25). Major mergers have mass ratios greater than fbulge , resulting in the bulge and disc stars of both galaxies plus all new stars formed in the burst being placed in a bulge component. Minor mergers have mass ratios less than fbulge , and the stars already present in the smaller of the two galaxies are placed in the disc component of the post-merger galaxy. N-body simulations by (Walker et al. 1996) show that nearly all (90%) of the satellite mass is stripped away and distributed in the disc of the larger galaxy. In contrast, all the newly formed stars end up in the bulge component. In our current iteration of the semi-analytic model we adopt the latest results of Cox et al. 17 (2005) simulations. These simulations differ from previous simulations in important ways. The primary differences are as follows: 1. The version of SPH used by Cox et al. integrates entropy, whereas Mihos & Hernquist (1996) used a version of SPH that integrated energy. 2. Star formation normalization used was different 3. Mihos & Hernquist (1996) represented the ISM as an isothermal gas, set at 104 K, whereas Cox et al. use adiabatic gas processes and shock heating. 4. Each simulation used a different disk-galaxy model. We adopt Cox et al. simulations and we refer the reader to their work for elaboration of why their models are the preferred choice. Based on Cox et al. simulations we adopt a mass threshold that will induce any sort of burst (5 to 10%). In prior work, typically all mergers induced star formation. Cox et al. found that 50% of the total gas supply is converted into stars – a somewhat lower efficiency than the previous simulations indicate. Consequently, galaxy mergers are less efficient at converting the available gas to stars than was previously thought. We use these results to guide our treatment of merger-induced starbursts, and we adopt Cox et al. values for our fiducial semi-analytic model run. Once star formation is triggered, it is modeled with an exponential function with a time-scale τburst and e-folding time-scale ηburst (see Eq. 2.13). ṁ∗,burst = ! Nburst 2 τburst (1 − eηburst ) " e−x (2.13) where x is given by, % % % ti − tpeak % % % x=% τburst % where Nburst is the burst normalization value equivalent to the fraction of cold gas that is used in the burst ('burst × mcold gas ), τburst is the burst time-scale, tpeak is the burst’s temporal peak defined 18 by ti + (τburst × ηburst ), with ti denoting the current time steps, and ηburst defines the number of e-foldings to the peak of a burst. After each burst the burst parameters are reset if the new burst fuel trumps the remaining fuel in any ongoing burst. The efficiency of the burst 'burst is defined as the fraction of the cold gas reservoir of the two merging galaxies that is turned into stars over the entire duration of the burst. In our treatment, we model the efficiency as a power-law function of the mass-ratio of the merging galaxy pair (see Eqs. 2.14 and 2.15). In accordance with the N-body simulation results described above, we differentiate between galaxies with bulges and those without, in order to take proper account of unequal-mass (minor) mergers. Generally, galaxies with significant bulges will have a stronger dependence on the power index since the burst efficiency is diminished in the presence of a bulge. 'burst = '0burst bulge ! msmall mbig "αburst bulge where '0burst bulge is the burst efficiency, αburst bulge is the mass ratio power index, and (2.14) msmall mbig is the mass ratio of the merged galaxies. The burst time-scale (τburst ) is equivalent to the dynamical time of the halo which is controlled by a burst length time-scale parameter. If there is no bulge, then a corresponding burst length time-scale parameter is used together with, 'burst = '0burst ! msmall mbig "αburst (2.15) In each case, msmall refers to the smaller value between mbar1 and mbar0 , whereas mbig refers to the larger value. The mbar1 and mbar0 parameters are defined as the total baryonic mass contained in the halos (the stellar mass contained in the disk, the bulge, and the baryons locked into the cold gas phase) of the merged galaxies. In cases where the halos have no baryons present, the ratio of the masses is taken between the merging halo masses. Fig. 2.3 illustrates the behavior of burst efficiency as a function of the mass ratio of the two merging galaxies. 19 Burst Efficiency 0.8 eburst 0.6 0.4 0.2 0.2 0.4 0.6 0.8 Mass Ratio Figure 2.3 This figure illustrates the efficiency of star formation in a burst as given by Eqs. 2.14 and 2.15. The x-axis denotes the baryonic mass ratio of the merging galaxies. The y-axis denotes the star formation efficiency of the resulting burst. The solid line corresponds to the case of αburst = 1.0. The dotted, dot-dash, and dash curves correspond to αburst values of 0.5, 1.5, and 10.0, respectively. In each case the value of '0burst was set to unity. In our nominal simulations, a galaxy with no bulge would take an αburst value of less than unity, and a galaxy with a bulge would take an αburst value greater than unity. The net effect would be that when a bulge is present, the burst efficiency drops off more rapidly at lower mass ratios. 20 2.2.6 Quiescent Star Formation Apart form starbursts we need to take account of regular (non-merger induced) star forma- tion, commonly known as quiescent star formation. In Somerville & Primack (1999) and Somerville, Primack, & Faber (2001), the authors investigated a variety of quiescent star formation laws. Here we give a brief overview of those scaling laws, and we conclude by noting the forms used in this work. The simplest assumption for quiescent star formation rate can be expressed in the following general expression ṁ∗,quies = mcold gas τ∗ (2.16) where mcold gas is the total mass of cold gas available in the disk and τ∗ is a free parameter that can be adjusted to match observations and denotes the time-scale at which the cold gas is converted to stars. This time-scale can be independent of any other physics or it can be a function of circular velocity, or dynamical time of the disk, or some other physical variables. We start with the most basic form of star formation in which cold gas is converted to stars with the same efficiency in disks of all sizes and at all redshifts. The scaling law then takes the following form ṁ∗,quies = τ∗ = τ∗0 (2.17) mcold gas τ∗0 (2.18) where τ∗0 is a constant. A more sophisticated form of star formation is a one with variable efficiency. One choice is to allow the star formation time-scale to scale with the circular velocity of the galactic disk in the form of a power law (see Fig. 2.4). We then have τ∗ = ṁ∗,quies = τ∗0 ! v0 vc "α∗ mcold gas # $α∗ τ∗0 21 v0 vc (2.19) (2.20) where vc is the circular velocity of the galactic disk, v0 is an arbitrary normalization factor (set to 300 km s−1 in Somerville & Primack (1999)), and τ∗0 and α∗ are free parameters. This model has a strong dependence on the circular velocity of the galaxy, where star formation is less efficient in halos with small vc . In this type of model, one expects a delay in star formation until lower redshift, since, in hierarchical models, halos at higher redshift are typically less massive and thus have smaller circular velocities. Note that there is no explicit dependence on the redshift in this scenario. We can introduce redshift dependence by setting the star formation time-scale proportional to the dynamical time of the disk. We then have τ∗ = τ∗0 tdyn (2.21) mcold gas τ∗0 tdyn (2.22) ṁ∗,quies = where τ∗0 is once again a free parameter, and tdyn is the dynamical time of the galactic disk that scales with rdisk vc . In Somerville & Primack (1999) the value of rdisk was set to one tenth the virial radius of the dark matter halo, and vc was set to be the circular velocity of the halo at the virial radius. In the case of satellite galaxies, the dynamical time was fixed to the value it had the last time the satellite galaxy was the central one. In this model, the star formation rate is nearly constant over circular velocity, but has a higher efficiency at earlier times (high redshift). This is because while the spherical collapse model predicts that the virial radius scales with vc as rvir ∝ vc , the virial radius of a halo with a given circular velocity increases over time with rvir ∝ (1 + z)−3/2 (for an Einstein-de Sitter universe). The dynamical time at a given redshift is then nearly independent of the galaxy’s circular velocity, and at higher redshifts the density of collapsed halos is higher and so the dynamical times are shorter and thus the available cold gas is converted into stars at a faster pace. The dynamical time dependent model is more proficient at forming stars earlier then the previous two models (constant and power-law, Eqs. 2.18 and 2.20). The latest iteration of our semi-analytic code incorporates two variants for the quiescent 22 Quiescent Star Formation Rate 0.8 ṁ,quies 0.6 0.4 0.2 200 600 1000 Vc Figure 2.4 Quiescent star formation rate where the star formation time-scale depends on the circular velocity of the disk. This figure illustrates how varying α∗ affects the behavior of star formation rate as a function of circular velocity. In this case the value of τ∗0 is set to unity and mcold gas is set to 107 M# (Eq. 2.20). The circular velocity normalization factor is fixed to v0, sf = 200 km s−1 , which is the value used in our model runs and is set to the value of Cole et al. In the figure, the x-axis corresponds to vc ranging from 1 to 1200 km s−1 , and the y-axis corresponds to star formation rate ranging from 107 to 108 M# yr−1 . The solid line corresponds to α∗ = 1.0, or a case of a linear relationship. The dotted, dot-dash, and dash curves corresponds to α∗ values of 0.5, 2.5, and 5.0, respectively. Note that all the curves intersect at the fixed V0,sf and mcold gas values. The case of α∗ = 0.0 would correspond to a horizontal line denoting circular velocity independence. 23 star formation rate: mcold gas $α∗ # ṁ∗,quies = τ∗ v0,sf vc (2.23) that is, the circular velocity is incorporated for the two modes of quiescent star formation. As before, mcold gas is the total mass of cold gas available in the disk, vc is the circular velocity of the galactic disk, and v0,sf is a normalization factor (set to 200 km s−1 , using Cole et al. value). The values of τ∗ and α∗ are allowed to vary. The time-scales for the two modes are τ∗ = τ∗0 (2.24) τ∗ = τ∗0 tdyn (2.25) the first one is just the familiar constant efficiency time-scale, while the second one is the time-scale that varies with the dynamical time of the disk. In each case τ∗0 is a free parameter. The quiescent star formation rate equations then take the from, ṁ∗,quies = ṁ∗,quies = mcold gas # $α∗ v 0,sf τ∗0 vc mcold gas # $α∗ τ∗0 tdyn v0,sf vc (2.26) (2.27) While the quiescent star formation is taking place, the merger-induced star formation is still active, and its contribution is typically far more significant. The total star formation rate for a galaxy is then set to the total of the burst and quiescent modes. Fig. 2.5 depicts sample star formation histories that include merge-induced and quiescent components of star formation. 2.2.7 Supernovae Feedback In our models, the supernovae feedback is modeled using either the disc-halo (first intro- duced in Somerville & Primack (1999)), power-law, or Martin-Heckman recipe. For our project we 24 Figure 2.5 The total star formation rate for the largest progenitor of the central galaxy within a halo with a present-day circular velocity of 220 km s−1 . All three models contain constant efficiency quiescent star formation. The top panel shows the model with no bursts, the middle panel shows the model with bursts in major mergers only, and the bottom panel shows the models with bursts in major and minor mergers. (This figure was reproduced, with permission, from Somerville, Primack, & Faber (2001)) adopt the power-law model as the de facto feedback recipe. Over the several years, the disk-halo recipe has fallen out of favor, and indeed we find it somewhat inadequate. However, for completeness, we present all the feedback variants. In the disk-halo model, the rate of reheating of cold gas is given by ṁrh = 2 '˙SN 2 vesc (2.28) 2 where '˙SN is the rate at which energy is injected into the cold gas by supernovae, and vesc is the mean escape velocity of the disc or halo. The reheating rate and ejected gas mass is calculated seperately for halo and disk components. The supernovae energy rate is defined as follows, 25 '˙SN = '0SN ESN ηSN ṁ∗ (2.29) where ESN = 1051 ergs is the total (kinetic and thermal) energy per supernova, ηSN is the number of supernovae per solar mass of stars (ηSN = 7.4 × 10−3 (Bruzual & Charlot 1993)), and ṁ∗ is the star formation rate. The escape velocities for the disk and the halo components are given by, vesc disk = 7.1 × 10 −5 × & mcold gas + m∗ rdisk √ vesc halo = 2 vvir (2.30) (2.31) Beside the disk-halo recipe, we can use one of the two simpler feedback models. The Martin-Heckman model assumes a simple feedback rate where the feedback rate is proportional to the star formation rate, ṁrh = '0SN ṁ∗ (2.32) a slightly more sophisticated recipe scales the feedback rate with circular velocity in the form of a power-law, ṁrh = frh ṁ∗ (2.33) where, frh = '0SN ! vc v0,fb "−αrh (2.34) where vc is the circular velocity of the disk, v0,fb is a normalization factor chosen so that '0SN is of order unity (this is fixed to a value of 200 km s−1 in our models), and αrh is a free parameter. In the Martin-Heckman and power-law models the fraction of gas that is ejected is governed by a preset ejection criterion – veject . If the halo’s virial velocity is less than the ejection threshold then all of 26 the gas is ejected (this is fixed to a value of 100 km s−1 ). In the disk-halo model, the fraction of the gas that is ejected is given by feject = 2 ! vesc disk vesc halo "2 (2.35) The gas and metals that are ejected from the halo are re-incorporated. The material is distributed outside of the halo with a continuation of the isothermal r−2 profile that we assumed inside the halo. If the total mass of the halo increases in value by a factor of two then all of the material is re-incorporated back into the halo. This material falls ingradually as the virial radius of the halo increases due to the falling background density of the Universe. 2.2.8 Chemical Evolution Chemical evolution is treated by assuming a constant mean mass of metals produced per mass of stars, denoted by Y (true yield). The produced metals are first deposited into the surrounding cold gas, at which point they may be ejected from the disk and mixed with the hot halo gas. In the disk-halo feedback model, these metals may also be ejected from the halo, in the same proportion as the reheated gas. The metallicity of any newly formed stars is set to equal the metallicity of the ambient cold gas at the time of formation. It should be noted that since the enriched gas may be ejected from the halo (using the disk-halo feedback), this treatment of chemical evolution is not equivalent to the standard closed-box model. 2.2.9 Stellar Population Synthesis In this project we use the Bruzual & Charlot (2003) stellar population synthesis model to generate the Spectral Energy Distributions (SED) for the stellar populations produced in our models. Briefly, the model assumes an Initial Mass Function (IMF) for the stars, which gives the distribution of the fraction of stars created within a given mass bin. In our case we use the parametrization made by Chabrier (2003b) of the single star IMF in the Galactic disk: 27 φ(log m) ∝ + * mc )2 exp − (log m−log , for m ≤ 1M# , 2σ2 m−1.3 , (2.36) for m > 1M# , with mc = 0.08M# and σ = 0.69. We chose the Chabrier (2003b) IMF because first, it is physically motivated, and second, it provides a better fit to the counts of the low-mass stars and brown dwarfs (see Chabrier 2001;Chabrier 2002;Chabrier 2003a). Furthermore, we adopt the lower and upper mass cutoffs of mL = 0.1 M# and mU = 100 M# . Once the IMF is in place the model stars are evolved in agreement with the theoretical evolutionary tracks for stars of a certain mass. In our case we use the Padova (1994) evolutionary tracks. The star formation recipe in our model then creates stars of a given age, which can then be assembled into a composite population. A synthetic ∗ spectrum of this composite population can then be generated. We use the parameter flum to set ∗ the stellar mass-to-light ratio (flum is defined as the ratio of the mass in luminous stars to the total stellar mass, m∗lum /m∗tot ). We set this factor to unity, effectively neglecting contributions from nonluminous objects (like brown dwarfs, planets, asteroids, etc). The SEDs are then convolved with the response functions intrinsic to ACS, ISAAC, IRAC, and various ground based observatories. This procedure gives us the photometric information necessary for comparisons with our observed LBG samples. Even though this field has been well studied, there are still many uncertainties associated with modeling stellar populations. To start with, the IMF is a major source of uncertainty. The IMF is fairly well determined in our Galaxy (Scalo 1986), but it is unknown whether this IMF applies universally and whether it depends on such factors as metallicity or other ambient effects. The results of our simulations are however not that sensitive to the upper and lower mass cutoffs as well as the slope of the IMF, because we are probing photometric quantities only. As mentioned, we use the Chabrier (2003b) IMF for our models. We find that this IMF gives the best representation of the IMF because it is physically motivated and gives better fits to the low-mass end. Besides the uncertainties surrounding the choice of the IMF there are difficulties with modeling the complex physics of stellar evolution. The major unreliable components (see Charlot 28 et al. (1996)) are the opacities, heavy-element mixture, helium content, convection, diffusion, mass loss, and rotational mixing. 2.2.10 Dust Extinction The effects of dust extinction are quite important due to the fact that the photometric data for our Lyman–break samples probe the rest-frame UV part of the spectrum. By studying correlation between the FIR excess (a reliable observational measure of bolometric extinction) and the far-UV spectral slope in nearby starburst galaxies, Meurer et al. (1999); Steidel et al. (1999) found an extinction at ∼ 1500 Å of a factor of ∼ 5. Assuming the same correlation for high-redshift galaxies, the UV spectral slopes of Lyman–break galaxies show an extinction of 4.7 in the bright (R < 25.5) Lyman–break population studied by Steidel et al. (1999). This extinction tends to increase for the most UV-luminous galaxies as shown by Meurer et al. (1999). In our treatment of dust we separate the overall face-on extinction in the V-band (τV ) and the dependence of the extinction on wavelength (the attenuation curve). The first component is treated via either a star formation power-law relation or the gas content and metallicity relation. The attenuation curve is selected from a choice of Calzetti, Galactic, or Charlot-Fall recipes. For the power-law variety, where the amount of dust for any galaxy scales as function of star formation rate, the face-on optical depth in the V-band is computed as follows, βdust τV, 0 = τdust, 0 (ṁ∗ ) (2.37) where τdust, 0 and βdust are free parameters typically set to match observations in the local universe. This power-law expression is fundamentally based on the empirical results of Wang & Heckman (1996) for nearby starburst galaxies. In the case of the gas-metallicity driven face-on extinction law, the face-on optical depth in the V-band is given by, τV, 0 , 1.36 × 10−14 × Zg × mcold gas = rgas 2 29 (2.38) where, rgas = fgas size × rdisk with fgas size and rdisk being the gas size and galactic disk radius respectively. The cold gas metallicity is given by Zg . Once the face-on optical depth is computed, the transmission function of the diffuse ISM is then calculated via an extinction law. The Galactic and Calzetti extinction curves have been used extensively in literature so we omit any detailed discussion here, however the Charlot-Fall recipe (Charlot & Fall 2000) is less well-known so we give a brief overview. In the Charlot-Fall recipe, plausible physical assumptions are made, from which the Calzetti attenuation curve is derived. Instead of being a purely data-derived construction, the Charlot-Fall recipe is based on physical fundamentals. The value of AV in the Charlot-Fall recipe is computed as follows, AV = ! λ 5500 "−ndust (2.39) where ndust is the dust extinction slope. The actual transmission function is then calculated as follows, TISM = ! 1 − ex x " (2.40) where, x= τλ cos incl where cos incl is the inclination angle of the galaxy and τλ is the optical depth at a given wavelength. Birth clouds are assumed to last approximately 10 Myr. The birth cloud transmission function is, 30 TBC = e−x (2.41) where, x = µ τV, 0 ! λ 5500 "−ndust where µ is the multiplicative factor for the τV, 0 parameter, which gives the face-on optical depth in the V-band of a birth cloud. The net transmission is then the sum of the TISM and TBC functions. 2.3 Fiducial Model Above we reviewed in great detail the semi-analytic model used in this work, but at this point we need to define a fiducial model that we will use as a reference model for the remainder of this work. The logic for a reference model is two-fold. It provides us with a fixed set of parameters that we can then vary individually to explore how models behave as a function of those parameters (see §4). In addition, the reference model will be used to test our color-selection criteria (see §3.7.2). The model that we choose is similar to the model used in Idzi et al. (2004), which was based loosely on models explored by Somerville et al. (1999) and Somerville & Primack (1999). The fiducial model is similar to those models in that it reproduces a mock-GOODS catalog with the same geometry, sky area, filter passbands, etc. as the real GOODS and faithfully reproduces some of the observations in the local universe (e.g. luminosity functions, colors, the Tully-Fisher relation, etc.) as well as properties of high-redshift galaxies (like dust extinction, colors, etc.). We adopt a power-law dust recipe (see §2.2.10), with a Calzetti attenuation curve, with τdust, 0 = 1.2 and βdust = 0.3 parameters. These parameters were adjusted so that we obtain an average extinction correction at 1500 Å of a factor of ∼ 5 for z ∼ 3 galaxies, typical of the Steidel et al. sample. For quiescent star formation, we adopt the recipe where the time-scale scales with dynamical time of the disk (see §2.2.6), and we choose τ∗0 = 12.0 and α∗ = 2.5. These values were chosen to again reproduce local as well as some of the distant observations (the luminosity functions, the Tully-Fisher relation, etc.). For 31 Table 2.1. Fiducial Model Parameter Choices Type Dust ··· Quiescent SF ··· Bursty SF ··· ··· ··· SNae Feedback ··· Recipe Power-Law ··· Dynamical Time ··· No Bulge ··· Bulge ··· Power-Law ··· Parameters Values τdust, 0 1.2 βdust 0.3 τ∗0 12.0 α∗ 2.5 '0burst 0.5 αburst 0.5 '0burst bulge 0.5 αburst bulge 1.5 '0SN 1.0 αrh 2.0 Select parameter choices displayed. To find all values for all other relevant parameters see §2 merger-induced star formation we adopt Cox et al. (see §2.2.5) values of '0burst = 0.5 and '0burst bulge = 0.5, αburst = 0.5 and αburst bulge = 1.5 parameters. For supernovae feedback recipe we choose the power-law recipe (see §2.2.7) with '0SN = 1.0 and αrh = 2.0 (Somerville et al. 1999). All other recipe and parameters choices were kept the same as stated elsewhere in §2, including, but not limited to choices of SED, IMF, metallicity, model resolution (halo circular velocities), etc. Table 2.1 summarizes some the parameter choices for our fiducial, mock-GOODS, model. Whenever we refer to a fiducial model, this will be the model we mean. 32 Chapter 3 Observational Data 3.1 Introduction to GOODS Observations of fields at high galactic latitude have long been an important tool in our quest to understand the high-redshift universe. Deep surveys, such as The Hubble Deep Field project (Williams et al. (1996) and Williams et al. (2000)) showed us the value of deep, multicolor imaging for studies of galaxy evolution. Such surveys have also provided a roadmap for successful public dissemination of the data and coordination of the best observations at all wavelengths on common survey fields (see Ferguson, Dickinson, & Williams (2000) for a review). The Great Observatories Origins Deep Survey (GOODS) is the progeny of such deep surveys. GOODS couples some of the deepest observations from space and ground-based facilities over the same field. The Hubble Deep Field North (HDF-N) and the Chandra Deep Field South (CDF-S) represent the two target fields. These are the most data-rich deep survey areas on the sky. Apart from HST and Spitzer data, numerous ground-based observations exist. In addition, deep X–ray observations from the CXO and XMM–Newton telescopes have been taken at these locations, and deep radio maps are also being generated. Deep multi-band observations over an extended and well-sampled wavelength range are 33 required to probe high-redshift universe in a comprehensive and statistically meaningful manner. The depth is necessary due to the intrinsic faintness of target sources. For example, a z850 > 26 (AB) is needed to detect a z ∼ 7 galaxy (assuming the same rest-frame UV luminosity function of Lyman-break galaxies at z ∼ 3 and z ∼ 4, (see Giavalisco et al. (2004b)). To actually measure the luminosity function, one has to go at least one magnitude fainter. The near-IR limits have to be around z850 ∼ 26 (AB), so that blue-source sensitivity is ensured. For mid-infrared wavelengths like those of the Spitzer Space Telescope IRAC instrument, the same requirements implies limits from a fraction to a few µJy. The well-sampled wavelength coverage is necessary in order to derive either accurate photometric redshifts or ascertain values of physical parameters of galaxies such as mass, age, metallicity, and dustiness. A well sampled wavelength range is also necessary to obtain sensitive color selection criteria. The GOODS project unites very deep observations from space and ground-based facilities in order to provide the first truly panchromatic deep survey over a relatively large area. The two GOODS fields, centered around HDF-N and CDF-S, cover a total of 0.1 degrees2 . The GOODS field centers (J2000.0) are 12h 36m55s ,+62◦ 14m15s , for the HDF-N, and 3h 32m 30s , −27◦ 48m20s , for the CDF-S. Each field provides an area of approximately 10% × 16% that is common to all the GOODS imaging observations. These observations include data taken with Chandra, HST, Spitzer, the ESO VLT, Subaru and NOAO. In addition, GOODS also includes spectroscopic coverage with the Keck, the VLT and Gemini. The HST Advanced Camera for Surveys (ACS) data consist of B435 , V606 , i775 , and z850 images, reaching a sensitivity level of 27.5, 27.9, 27.0 and 26.7 magnitudes (signal-to-noise ∼ 10 contained within 0.%% .5 diameter circular aperture). The Spitzer data consist of IRAC images at 3.6, 4.5, 5.8 and 8.0 µm reaching 0.11, 0.24, 1.35, 1.66 µJy depth, and of MIPS images at 24 µm reaching 12 µJy. An overview of the GOODS data used in this work is presented below. All of the GOODS data, raw and reduced, and some source catalogs are publicly available and can be obtained from the teams Web site (www.stsci.edu/science/goods/). Fig. 3.1 shows the CDF-S exposure map for the Chandra, ACS, and IRAC observations, while Fig. 3.2 shows target areas for all CDF-S 34 Table 3.1. Instrumental Data Facility CTIO 4-m + MOSAIC Passbands Area coveragea Angular resolutionb 1800 U 1.26 c CDF-S d HST + ACS BViz 320 0.125 ESO VLT + ISAAC JHKs 130 0.40-0.65 Spitzer + IRAC 3 .6 4 .5 5 .8 8 .0 320 1.6 a Total area covered, in arcmin2 . b PSF FWHM, in arcseconds c Field HDF-N + CDF-S CDF-S HDF-N + CDF-S The total area with V iz–band coverage is 365 arcmin2 . d Modal PSF FWHM of current version of drizzled image mosaics. data sets (except for Spitzer data). Tables 4.1 and 4.2 list pertinent instrumental data and actual sensitivities reached. In sections below we briefly describe each data set as well as the catalogs and samples that were produces as part of this work. In addition, we go over the TFIT software package used to produce reliable IRAC catalogs. All relevant simulations are discussed separately in §5. All quoted magnitudes throughout the this work are in the AB magnitude system (Oke 1974). Finally, although references are made to both the HDF-N and CDF-S data sets, we only make use of the CDF-S data sets in this work. 35 Figure 3.1 Exposure map of the GOODS CDF-S Observations. In this image, blue represents the Chandra (CXO) exposure map for the 2 Msec observations described by Alexander et al. (2003). Green represents the current HST ACS exposure map, and red represents the planned Spitzer IRAC exposure map. Where all fields overlap, the colors sum to give white in the representation. The different ACS tiling patterns on even and odd epochs produce the sawtooth pattern around the edge of the ACS fields. 36 Figure 3.2 Target areas of all data sets for CDF-S (Spitzer data excluded). 3.2 HST - ACS The HST ACS observations taken by GOODS consist of imaging in the F435W, F606W, F775W and F850LP passbands. While the B435 images were all acquired at the beginning of the survey, the V606 , i775 , and z850 images were acquired over five epochs, separated by 40 to 50 days to optimize the search for high-redshift supernovae. In the odd numbered epochs, each 10% × 16% field 37 Table 3.2. Data Sensitivity Facility U B V I z J H Ks 3.6 4.5 5.8 8.0 4–m MOSAIC 25.9 ··· ··· ··· ··· ··· ··· ··· ··· ··· ··· ··· HST ACS ··· 27.8 27.8 27.1 26.6 ··· ··· ··· ··· ··· ··· ··· VLT ISAAC ··· ··· ··· ··· ··· 25.5 24.9 25.1 ··· ··· ··· ··· Spitzer IRAC ··· ··· ··· ··· ··· ··· ··· ··· 0.11 0.24 1.35 1.66 For each telescope + instrument combination, the first line gives the 10σ point–source sensitivity within an aperture diameter of 0."" 2 for HST, 1."" 0 for ISAAC, and 2."" 0 for U-band data. Spitzer limits are given in µJy is tiled by a grid of 3 × 5 individual ACS pointings. Some overlap areas are generated in order to ensure photometric and astrometric consistency. For the remaining epochs, due to HST pointing constraints, the field is rotated by 45◦ and as a result a different overlapping tile pattern is generated. The B435 observations were gathered in the first epoch alone, using the familiar 3 × 5 grid, with six exposures per position.The typical exposure times are 1050, 1050 and 2100 seconds in the V606 , i775 , and z850 bands, respectively. There are two exposures in each of the V606 and i775 bands, and four exposures in the z850 band. This pattern ensures good rejection of cosmic ray events in the single epoch z850 bands, which is where the detection of transients is carried out. The telescope field of view is dithered by a small amount between individual exposures to allow optimal sampling of the point–spread function and to remove detector gaps and artifacts. For final reductions, the multiple epochs are combined into a single mosaic, allowing cosmic ray rejection from at least six images per band. The final, total exposure times are approximately 7200, 5250, 5250, and 10500 seconds in the B435 , V606 , i775 , and z850 bands, respectively. Initial reduction of the data was carried out by the ACS calibration pipeline calacs. The process consists of basic calibration steps of bias subtraction, gain correction, and flat-fielding (Pavlovsky et al. 2002). The pre-reduced data are then further processed by the GOODS pipeline using the multidrizzle script (see Koekemoer et al. (2003) for details). The net result is a set of 38 images that have been geometrically rectified and cleaned clean of cosmic rays. These preliminary reductions – the GOODS public release v0.5 – have been released via the Multimission Archive at Space Telescope (MAST). The geometric distortion model used in the preliminary reductions described above had significant flaws that were revealed in the overlap regions. To remedy this, a new astrometric solution was derived for each tile and each epoch using a list of matched sources from the GOODS ground based images. For the CDF-S image, the Wide Field Imager (WFI) R band image was used (see §3.5.2 for WFI data description). The WFI R mosaic was in turn astrometrically calibrated to the Guide Star Catalog 2 (GSC-2) and put on the ICRS reference frame. For HDF-N, the reference image was an R-band Subaru image of the field (Capak et al. 2003). The new astrometric solution for the z850 mosaic was derived by performing a least-squares optimization of the position, orientation, x and y pixel scales, and axis skew of each tile and epoch, minimizing the inter-epoch variations of the estimated position for ∼ 2000 sources. As a result, the estimated rms in the source position, internal to the solution, is roughly 0.1 to 0.2 WFC pixels. The new z850 image astrometric solution was propagated to the remaining ACS bands by a tile-to-tile matching to the z850 mosaic source positions. The resultant solutions had a residual rms of about 0.3 pixels, with larger deviations in some localized regions across the field. Once astrometry was firmed up, all exposures were then drizzled (Fruchter et al. 2002) onto a series of images with a common pixel grid, so as to create a clean median image, which was subsequently used to create cosmic ray masks for each exposure. As a last step, the individual exposures were drizzled using the new masks onto a final monolithic mosaic for each band, measuring 18000 by 24000 pixels with a scale of 0.%% 05/pixel. While the improved astrometry works well, there are a few faults that need to be noted. The deficiencies become apparent for bright stars, where the cosmic ray rejection algorithm rejects some good pixels due to slight misregistrations issues. This effect can bias fluxes faintward for brighter point sources. This effect applies only to the V606 and i775 mosaics. However, a direct comparison of the v1.1 GOODS mosaics with the original WFPC-2 HDF-N reveals systematic errors of less than 0.01 magnitude for SExtractor MAGAUTO magnitudes in the range 23 < 39 V606 < 26, with an rms scatter less than 0.2 magnitude. With the new v1.9 reductions (used in this work) additional improvements have been made. These include: Fixing the slight sky level variation, masking of satellite trails, perfecting ghost reflection. In addition, supplemental exposure time has been added, which include 4 exposures through the z850 filter over 15 tiles, and a single exposure through both i775 and V606 filters over 15 tiles each. The supplemental exposures have effectively added 7712, 1908, and 330 seconds to the z850 , i775 , and V606 bands, respectively. With the new reductions we reach ,S- N z850 ∼ 5 at z850 ∼ 28. The reader is urged to refer to the teams Web sites (www.stsci.edu/science/goods/) for the latest status on GOODS ACS mosaic reductions. 3.3 ESO VLT - ISAAC As part of the GOODS program, near-infrared imaging observations of CDF-S have been carried out in the J, H, Ks bands, using the ISAAC instrument mounted at the Antu Unit Telescope of the VLT at ESO’s Cerro Paranal Observatory, Chile. This work has been conducted as part of an ESO Large Programme. To cover the GOODS CDF-S field, 32 pointing have been used. The resultant mosaics cover ∼ 159 and ∼ 160 %2 in the J and Ks bands, respectively. The H-band covers ∼ 127 %2 . The J, H, and Ks data consists of 21,19, and 23 tiles, respectively, with each tile spanning 2.5.% × 2.5.% . All images have a pixel scale of 0.15”, which is exactly a factor of five larger than the pixels in the GOODS ACS images. The data have an excellent image quality with a median seeing value of ≈ 0.%% 45 for all bands.The seeing dispersion across tiles is extremely small for the H band, less than 0.%% 05, somewhat larger for the J band, and largest for the Ks -band, at around 0.%% 15. The dispersion within each tile is extremely small. The astrometric calibration was derived using a reference catalog generated from a deep R band WFI image which was astrometrically calibrated using the Guide Star Catalog GSC–2.3. The astrometry has been compared by the GOODS team with calibrated data from the HST ACS. An astrometric matching to the ACS list of unresolved sources shows a rms scatter in astrometry of 0.1” across the entire area. 40 The photometric calibration of the present ISAAC data was done against the J, H, and Ks mosaics constructed from photometrically calibrated SOFI images of the EIS-DEEP and DPS infrared surveys conducted over the same region (see §3.5.3 for SOFI data description). The SOFI images encompass a number of tiles of the ISAAC mosaic, yielding better relative calibration across the entire surveyed area. Zeropoints for each ISAAC field were determined using SOFI images and a sample of ∼ 400 unresolved sources. These sources have been identified in the HST ACS images based on SExtractors stellarity index and flux ratio, yielding a list of potential stars. All ISAAC images were first PSF-matched to the value of the corresponding SOFI image (∼ 0.9%% ) employing Gaussian convolution. Aperture magnitudes of these stars were then used to determine zeropoints for each individual tile in the AB system. Anywhere from 3 to 12 sources have been used per each tile. This procedure yielded zeropoints with rms values ranging between 0.01 and 0.06 magnitudes in J-band, up to 0.17 magnitudes in H-band, and between 0.01 and 0.08 magnitudes in Ks -band. For the tiles where less than three isolated stars were available for accurate photometry all high signal-to-noise sources that qualitatively appeared pointlike in the ISAAC images were used for calibrations. To provide a homogeneous photometric zeropoint across the entire GOODS field, all images were rescaled to a set zeropoint of 26 (AB). The exposure times were also normalized to unity, so that AB magnitudes in all released fields, including the mosaics, could be easily obtained via mag(AB) = -2.5 × Log[flux] + ZP. The following corrections were applied: J(AB) = J(Vega) + 0.90, H(AB) = H (Vega) + 1.38, and Ks (AB) = Ks (Vega) + 1.86. To take account of any potential systematic errors in this calibration procedure, independent photometric calibration checks had to be made. Cross-checking was done against the 2MASS photometry using limited number of stars in the field. The photometric zeropoints were found to be consistent to within few percent. A comparison of the present release data with photometric catalogs from Saracco et al. (2001) (J and Ks bands), Cimatti et al. (2002) (Ks -band), and Moy et al. (2003) (H-band) did not reveal any systematic differences once error margins were taken into account. 41 2.0 5.8 8.0 3.6 4.5 1.5 1.0 0.5 2.0 1.5 1.0 0.5 0.5 1.0 1.5 2.0 0.5 1.0 1.5 2.0 Figure 3.3 Illustration of the exposure layout for each IRAC epoch and channel combination in CDF-S. The green and blue points correspond to epoch 2 and epoch 1 sources, respectively, whereas the red points correspond to dual-epoch sources. 3.4 Spitzer - IRAC The GOODS Spitzer Legacy program observations cover two fields on the sky, the CDF-S and the HDF-N. IRAC data consists of four channels, 3.6, 4.5, 5.8 and 8.0 µm taken in two epochs separated by six months. The telescope orientation is dithered and rotated by 180◦ between the two epochs. All four channels are used simultaneously, with two channels pointing in one direction, and the other two in different direction. Fig. 3.3 illustrates the layout of the CDF-S IRAC observations by epoch. This scheme results in full four-channel coverage of the 10% × 16% GOODS field, with 23 hours worth of exposure per epoch, and double that in the overlap region. The IRAC data is pre42 processed by the Spitzer Science Center (SSC) Basic Calibrated Data (BCD) pipeline. The data is then post-processed by applying various corrections such as median image subtraction, background subtraction, cosmic ray and bright sources corrections among others. The next step involves deriving internally consistent astrometric solution. Images are then combined using procedures akin to the multidrizzle method used in ACS reductions. Finally, exposure, weight, and flag maps were generated. The weight maps were re-normalized to inverse variance maps, where the inverse variance maps represent only the shot noise component of the image noise at the sky background level of the images, and do not include the Poisson shot noise from the sources themselves, nor any measure of photometric uncertainty due to image crowding or confusion noise. The flag maps are bit maps that take into account data defects like residual muxbleed (bright source effect), low exposure time, or simply no data available. A comprehensive discussion of GOODS Spitzer data acquisition and reduction can be found in the forthcoming data paper by Dickinson et al. 3.5 3.5.1 Ancillary Data CTIO 4m - MOSAIC U Observations of the GOODS CDF-S field through the U -filter were taken with the MO- SAIC camera mounted on the CTIO 4-m telescope. The data was taken over a period of two runs (2003, 2004) and it consists of 26 hours of total exposure time. The conditions during both runs were photometric with mean seeing of FWHM ∼ 1.%% 26. As with the KPNO observations, the data was reduced with the IRAF mscred package. The package is used to carry out bias subtraction, flat– fielding, geometric distortion correction, removal of amplifier cross–talk, subtraction of an additive pupil ghost, image registration, and the subsequent combination. Individual exposures were registered against the GSC 2.0 database, whereas the final mosaic was astrometrically checked against our reference WFI R mosaic. The WFI R is our standard astrometric reference for ground based data. The final mosaic combinations were done with the SWarp package (Terapix). SWarp is a 43 program that resamples and co-adds together images using any arbitrary astrometric projection as defined in the WCS standard. The use of the SWarp package was necessary because part of the data had astrometric anomalies in the top two corners of images. The anomalies were most likely due to a U -filter change in the middle of one of the observing runs. As a result, it was necessary to produce two separate mosaics, one with a full field of view, but shallower due to elimination of the faulty frames. The second mosaic was produced by masking out the faulty regions, resulting in a smaller but deeper mosaic. The final exposure times for the two mosaics were 20 and 25 hours, respectively. Unless otherwise stipulated the second, deeper, mosaic was used for this work since it completely overlaps the ACS region. This data set was used to select U-dropout galaxies. 3.5.2 ESO MPI 2.2–m - WFI The WFI instrument, mounted at the top of the ESO-MPI 2.2-m telescope, was used to image about ∼ 0.4 sq. degrees around the CDF-S, using its U % U BV RI passbands. We refer the reader to Arnouts et al. (2001) for a complete description of the full data set. Supplemental exposures in the B, V , R filters were taken as part of the COMBO-17 project (Wolf et al. 2001). All of the data, including EIS, GOODS, and COMBO, were reduced in a uniform manner using the GaBoDs WFI reduction pipeline (Schirmer et al. 2003). Photometric calibration was performed using the color loci of stars. These were then compared to synthetic color-color diagrams generated using the Gunn & Stryker (1983) spectro-photometric library and our passbands. The resultant zeropoints were then adjusted as needed, and are now accurate to < 0.1 magnitude. The 10σ point–source sensitivity within an aperture diameter of 2.%% 0 is ∼ 25.8 (AB) in R-band. The mosaic covers an area of 1350 arcmin2 with a variable angular resolution of 0.85–1.05 arcsec. This data set was used to provide a common astrometric reference frame for all data. It should be noted here that the WFI R mosaic is our de-facto astrometric reference for the GOODS ground based CDF-S data sets. 44 3.5.3 ESO NTT - SOFI Near-infrared data in the J and Ks bands for the CDF-S were obtained with SOFI on the NTT as part of the EIS. The observations and reductions are described in Vandame et al. (2001). The observations consist of 4 × 4 grid of pointings covering 0.1 sq. deg in 5% × 5% tiles. SOFI Hband data were obtained and reduced by Moy et al. (2002), and cover a larger area. Photometric zero-points were checked by the GOODS team by comparing photometry of stars to measurements from the Two-Micron All-Sky Survey (2MASS). The 10σ point–source sensitivity within an aperture diameter of 2.%% 0 is ∼ 22 (AB) in all bands covering an area of 360 (630 for H-band) arcmin2 with a variable angular resolution of 0.65-1.05 (0.55-0.85 for H-band) arcsec. This data set was used to calibrate the ISAAC photometry. 3.6 3.6.1 Photometric Catalogs SExtractor Catalogs Throughout this work we use several different source catalogs to compile the photometric information required for the Lyman-break galaxies used in this work. As described in §3.6.2 we use the TFIT package to extract reliable photometric fluxes. However, while TFIT is extremely useful, we still rely on other source-extraction packages, namely the SExtractor package developed by Bertin & Arnouts (1996). TFIT itself requires an SExtractor-like utility for its data preparation purposes, we make use of SExtractor to procure source lists and segmentation maps. The Lyman-break galaxy samples used in this work (§3.7.2) were compiled using SExtractor catalogs of the U-band and ACS images. Lastly, SExtractor-based catalogs of ACS and IRAC data sets were used to calibrate the TFIT software and the resultant catalogs (see §3.8). The ACS SExtractor catalogs were constructed with the goal of optimizing the detection of faint galaxies while at the same time keeping spurious sources to a minimum. This was accomplished by fine-tuning the detection thresholds and the size and shape of the convolution kernel. Sources 45 Figure 3.4 Sample plot of completeness limits on the ACS z850 Sextractor catalog as a function of half-light radius and total magnitude for both elliptical and spiral galaxies. This plot is based on the v1.0 ACS data set – a shallower data set. The data set used in this work is deeper. were first detected in the z850 mosaic, and then photometry was carried out through matched apertures in the remaining ACS bands. Photometric uncertainties were then computed internally using the normalized ACS noise maps and externally through detailed simulations using artificial sources. Monte-Carlo simulations were carried out to ascertain the completeness of our catalogs. The description of these simulations can be found in §5.1. Fig. 3.4 shows a sample plot yielded by the simulations, which shows completeness limits on our ACS z850 SExtractor catalogs as a function of half-light radius and total magnitude. Apart from ACS SExtractor catalogs the GOODS team has also produced IRAC and ISAAC SExtractor catalogs. As was the case with the ACS SExtractor catalogs, these catalogs were 46 created using the best possible SExtractor values to fine-tune the photometry. The primary purpose of the IRAC catalogs was for TFIT calibration work. The IRAC catalogs were derived individually for each channel and epoch combination. In the case of ISAAC catalogs, the SExtractor-derived fluxes were used for some of the work in this project, although no ISAAC data were used for the actual fitting. The ISAAC is much shallower than the IRAC data and so incorporating this data into our analysis would severely limit our Lyman-break samples. Nevertheless, the ISAAC data was useful for other parts of out work (such as exploring ACS-ISAAC colors), so a Ks -band detected catalog was produced with matched J and H photometry. We then processed the catalogs to correct the NIR magnitudes so that they could be used alongside our ACS magnitudes. We accomplished this by correcting each ISAAC isophotal magnitude with a correction factor determined from the isophotal and total magnitudes. This provided as with a reliable way (at most ∼ 0.1 magnitude error), of mixing the ACS and ISAAC magnitudes for our ACS-ISAAC color comparisons without having to produce matched SExtractor ACS-ISAAC catalogs. We wanted to treat the two data sets (ACS and ISAAC) separately since we needed to retain the full resolution of ACS mosaics for our TFIT ACS-IRAC catalogs. Producing matched SExtractor ACS-ISAAC catalogs would have called for seriously degrading the ACS mosaics. The ultimate solution of course is to produce TFIT ACS-ISAAC catalogs. Whenever ISAAC data is used in this work we explicitly refer the reader to the caveats just described. 3.6.2 TFIT Catalogs The IRAC photometric catalogs used in this work were constructed using a template-fitting package called TFIT. The TFIT software is described in some detail in §3.8.1 along with diagnostics and calibrations. For full details on how TFIT works we refer the reader to Laidler et al. (2006) (in preparation). Here we briefly describe the TFIT catalogs used in this work, information on SExtractor catalogs (like those for ACS) can be found in §3.6.1. The TFIT catalog is ACS-to-IRAC, where we use SExtractor-derived ACS sources and use TFIT to fit the IRAC fluxes. The ACS z850 - 47 IRAC catalogs were created by template fitting each field, channel, and epoch of IRAC to the ACS z850 data. Since we have 2 fields, 4 channels, and 2 epochs of IRAC data (see §3.4 for full data description) this resulted in 16 separate catalogs, although in this work we use CDF-S data only. For each catalog, channel-field-epoch specific PSFs were used. Most of these PSFs were provided by SCC (see §3.4). Once we were satisfied with the raw catalogs produced by TFIT we produced final catalogs by assembling the 2 epochs for each field-channel combination. Each source then had either data from a single epoch or from both epochs. In the case of dual-epoch data, we used weighted flux and weighted flux error for those objects that had reliable photometry in each epoch according to the following prescription, fe12 = fe1 × w1 + fe2 × w2 w1 + w2 1 σe12 = √ w1 + w2 where fe is the flux for each epoch, and w1 = 1 2 , σe1 w2 = 1 2 σe2 (3.1) (3.2) are the weighted flux errors. In addition to the above information we also propagated flags from the original IRAC flag maps. These flags were then used to separate spurious sources from good data. Because of the way TFIT works, we could then easily merge all SExtractor-derived ACS photometry with the TFIT-derived IRAC photometry to produce master catalogs. These pan-chromatic catalogs (z850 through IRAC 8.0) were then used to extract photometric information for the Lyman-break samples that were separately constructed using SExtractor-derived U-band and ACS data. 48 3.7 3.7.1 Galaxy Samples Lyman Break Galaxies The Lyman-break color selection technique has been shown to be a highly effective means of > 2) (Steidel et al 1999; Madau et al. 1996). The Lyman-break selecting galaxies at high redshift (z ∼ technique, as the name implies, exploits the intrinsic Lyman edge in galaxies and the opacity of intergalactic neutral hydrogen to separate galaxies located at high and low redshifts. Even though galaxies exhibit smoothly varying spectra, where the flux is usually a slowly varying function of wavelength, there a few discontinuities. Most notably, the Lyman-break (912 Å) and the Balmer break (∼ 4000 Å). It is the first of these two that is used to photometrically select high redshift galaxies. Photometric color criteria that identify the Lyman-continuum break have been shown, through spectroscopic work, to be quite successful at picking out a substantial population of high redshift galaxies (Steidel et al. 1996a,b). Over the past decade, fairly large samples of Lymanbreak galaxies (LBGs) in the redshift range z > 2 have been compiled, and the characteristics of these objects have been closely examined. Contemporary surveys, such as GOODS, can identify < z < 5.5 with varying degrees of success depending on the high redshift galaxies in the range 2.5 ∼ ∼ redshift slice (Giavalisco et al. 2003b). The GOODS samples of Lyman-break samples are identified via color selection criteria as well as signal to noise considerations derived for each dataset. The selection criteria are largely based on previous experience with Lyman–break galaxies (e.g. Dickinson 1998; S99; Steidel et al. 2003). They are visually fine–tuned based on the observed colors of stars and galaxies in the ACS images, as well as on the ACS synthetic photometry from galaxy spectral templates. This procedure rejects most interlopers from lower redshifts, while efficiently detecting typical UV–bright, star–forming galaxies at redshifts of interest. The color selection criteria are further fine-tuned via artificial galaxy simulations. This is accomplished by modeling the HI cosmic opacity as a function of redshift, including scattering in resonant lines of the Lyman series and Lyman-continuum absorption, and the 49 use of stellar population synthesis models with a wide variety of ages, metallicities, dust contents, and redshifts, to derive color selection criteria that provide a robust separation between high redshift and low redshift galaxies. Of course, due to a multitude of possible star formation paths for any particular galaxy and the complex nature of chemical evolution of stars, the interstellar medium, and the dust distribution and content, Monte-Carlo simulations have to be performed to ascertain the robustness of the selection criteria. The color criteria can also be tested against spectroscopic samples to confirm the efficiency of photometric selection as in (Steidel et al. 1996b). GOODS has been gathering spectroscopic data and that information has been used to verify and refine our samples. Because of the nature of this project we also contrasted our Lyman-break samples against our nominal semi-analytic model (see §3.7.2). The advantage of the photometric technique is its ability to rely on photometry and simulation alone to reliably identify distant star forming galaxies. In addition, the photometric technique goes deeper, yielding larger samples. Spectroscopic work in often an expensive endeaver as it requires long exposure times and individual measurements for each galaxy. In addition, many of the distant objects are not easily accessible even with the most powerful telescopes. The advent of multi-slit spectroscopy and more powerful telescopes will make it easier to obtain useful spectroscopic integrations for many objects at a time, and indeed GOODS has been using the multi-slit approach to obtain spectroscopy for select objects in the GOODS field. Nevertheless, for medium to large area surveys, the preferred techniques is the photometric one. The deficiencies of the photometric technique lie in the uncertainties of redshift estimates as well as reliance on robust photometry. 3.7.2 Color Selection Criteria & Samples In this section, we shall define the color selection criteria appropriate to the GOODS bandpasses. The CTIO-U and ACS mosaics allow us to define several Lyman-break samples, namely, the U-, B-, V-, and i-dropouts. Below we give the color selection criteria used in this work. Unless otherwise stated, these are also the color selection criteria that have been applied to our model 50 galaxies in the course of our analysis. First, there are the U -band dropouts (z ∼ 3), which use the following criteria: (U − B435 ) >= −0.75 + 0.5 × (B435 − z850 ) & (3.3) (U − B435 ) >= 0.9 & (3.4) (B435 − z850 ) <= 4.0 (3.5) the B-band (B435 ) dropouts (z ∼ 4) are defined via: (B435 − V606 ) > 1.1 + (V606 − z850 ) & (3.6) (B435 − V606 ) > 1.1 & (3.7) (V606 − z850 ) < 1.6 (3.8) the V-band (V606 ) dropouts (z ∼ 5) are defined via: (V606 − i775 ) > (1.4667 + 0.8889 × (i775 − z850 )) || (3.9) (V606 − i775 > 2.0)) & (3.10) (V606 − i775 ) > 1.2 & (3.11) (i775 − z850 ) < 1.3 (3.12) and the i-band (i775 ) dropouts (z ∼ 6) are defined by: (i775 − z850 ) > 1.3 In each case we required potential dropout targets to have a (3.13) ,SN < 2 in the dropout band in order to be classified as undetected. In the bands that the object was detected, the 51 ,SN had to be greater than five. This selection scheme helps to reject interlopers. The samples were than visually culled to eliminate contaminants, like cosmic rays, stars, satellite trails, diffraction spikes, etc. We have stated i-band dropout color selection for completeness, but we shall ignore that sample in this work, since the quality and the number of dropouts is insufficient for our analysis. In addition, we will not use the V-band dropout sample in our analysis due to the dearth of objects as well as the lack of robust NIR photometry, but we do use this sample for projection and discussion purposes. The number counts for the U-, B-, and V-samples, with magnitude of z850 < 26.5) and ,SN ,SN > 10 in ACS (corresponding to a total > 5 in IRAC3.6 and IRAC4.5 bands are: 569, 275, and 53 galaxies, respectively. Including ISAAC J and Ks bands (with a ,SN > 5 cut) results in much lower number counts: 345, 91, 18, respectively. This is due to the much shallower depth of the ISAAC mosaic, but also partly to the fact that we have not applied TFIT to the ISAAC data. Adding extra IRAC channels, especially channels 3 and 4, diminishes the number counts as well, due to the shallower nature of those two channels relative to the first two. Therefore for our analysis we stick with ACS and IRAC (channels 1 and 2) for our samples, excluding IRAC (channels 3 and 4) and ISAAC data. We do however use the excluded channels for predictions and discussion purposes. In Fig. 3.6 to Fig. 3.11 we show color-magnitude diagrams for the U, B-, and V-dropouts, both for UV-continuum and Balmer-Break rest-frame colors. To test the completeness of our samples we use Monte-Carlo simulations described in §5.1. According to these simualtions, the B-dropout galaxies’ redshift distribution of the simulated colorselected sample has a mean value of z ∼ 3.91 with a standard deviation of ±0.44. The recovery percentage, using color criteria, is 87% for the simulated B-dropout galaxies down to z850 < 27 and in the redshift interval 3.47 < z < 4.35. When we apply the color criteria to the fiducial semianalytic model (see §2.3) run, we select 90% of all model galaxies in the same 3.47 < z < 4.35 redshift range, down to the same limiting magnitude of z850 < 27. This implies that the simulations and the fiducial semi-analytic model show concordant incompleteness estimates with respect to the B-dropout selection technique in the above redshift range and down to the given magnitude limit. 52 This is agreement of what we found in our previous work (Idzi et al. 2004). Similar exercises can be performed with respect to the other dropout samples. We find similar agreement for the V-dropouts, where the simulation and semi-analytic model completeness fractions are 82% and 88%, respectively, over a redshift range 4.65 < z < 5.35 (with the mean redshift derived from the simualtions). For the U-dropouts we cannot ascertain completeness limits from the simulations since our Monte-Carlo simulations do not incorporate U-band data. However, we can quote the fiducial semi-analytic completeness based on the mean redshift derived from that model. We find 92% completeness in the redshift range 2.32 < z < 3.68. As a fun exercise, we can plot the data-derived Lyman-break samples alongside our fiducial semi-analytic model-derived Lyman-break samples. Fig. 3.12 shows such a plot for B-dropout samples. 3.8 3.8.1 Template-Fitting Software Package TFIT Overview The TFIT (short for Template-Fitting) software package was initially developed by Pa- povich (2002) and since then it has been re-engineered by the GOODS team to speed-up processing time and also allow more flexibility. The purpose of this section is to introduce the reader to the TFIT software package. Here we will only provide a brief introduction, we refer the reader to Laidler et al. (2006) for the latest and the most complete discussion of TFIT. Since this work relies heavily on TFIT products we devote special attention to the calibration and diagnostic work in §3.8.2. The TFIT package, which will soon be released to the public through the Spitzer Science Center, addresses some of the most thorny issues surrounding the creation of photometric catalogs. These issues stem from a combination of IRAC’s nearly 2.%% resolution and the high density of sources found in the GOODS HST ACS fields (nearly 200 per arcmin2 ), a large fraction of which are distant galaxies with significant mid-IR fluxes present at the extreme sensitivities of the GOODS SST IRAC observations (1 σ = 22 nJy at 3.6 µm). The combination of these factors leads to significant source 53 crowding in the IRAC images. Any reasonably sized photometric aparture of an IRAC source is frequently contaminated by its neighbors. In addition, catalog matching of IRAC detected sources is compromised by de-blending issues. The typical existing workarounds, such as the DAOphot (crowded field, psf fitting) photometry package, are not suitable to our case. This is because the preponderance of our extragalactic sources are, at a minimum, marginally resolved with IRAC. As a result, a new approach had to be constructed in order to remedy these difficulties. The GOODS team has developed a crowded-field, resolved-source photometry package called TFIT. The basic flow of how TFIT processes data is shown in Fig. 3.13. Briefly, TFIT first constructs lower resolution (LR) (in this case - IRAC) template images for sources detected at higher resolution (HR) (in this case ACS) by using the high-resolution position and morphology along with PSF information about both images. In a final step, the TFIT package scales the templates to optimally match the lower-resolution image. In short, the TFIT package uses apriori knowledge of source location and morphology from a high resolution image to construct a low resolution version of the source. The main assumption to this method is that the intrinsic light profile of the source is identical, modulo PSF effects, in both the low and high resolution images. To facilitate the fitting process, the lower resolution input image is divided into overlapping cells, and the objects in the cells are all fit simultaneously using the technique of singular value decomposition (SVD) to solve the resulting matrix equation. This simultaneous fitting affords more accurate photometry due to the extra information coming from many galaxies (Laidler et al. 2006). The matrix equation takes the form: LR(image) = β + α1 T1 + α2 T2 + ... + αn Tn (3.14) where the Ti are the templates for the n objects that occur in the region. The quantity Ti is actually divided by Ei , where Ei is the rms error value for the relevant pixels in the LR image. This equation is solved to determine the best fit flux for each object in the LR image, plus a background term for 54 the cell. The best fit is generated by minimizing a χ2 statistic, using: 2 χ = . x,y / 12 0N i L & xy − β − i=1 αi Txy σxy (3.15) where Lxy and σxy are the fluxes and rms errors of the LR image. The fitted parameters, αi , are the scaling factors for cell objects, which are used to scale the individual object templates. The β parameter is a linear constant, which corresponds to the LRI background of the cell. The sum is performed over the entire cell. The SVD technique used to perform the actual χ2 minimization see Press et al. 1992) is ideal for this situation since many of the equations to be solved are overdetermined (more data points than parameters). In such cases, the matrix defined in equation (2) will occasionally be singular or nearly singular. The SVD technique circumvents this problem by transforming the matrix into a diagonal one containing singular values, and two non-singular, orthogonal matrices. As a result, the parameters to be fitted (αi , βi ) are linear combinations of the columns of the dot product of the orthogonal matrices and the data, where each column is properly weighted by the inverse of the near-singular values. The weight is artificially set to zero whenever any near-singular value is below some threshold. In addition to the best fit parameters, TFIT produces uncertainties on the resultant values that are based on the sum of the χ2 per degree of freedom in the cell and the variance of the parameters in the fit. A full covariance matrix is also returned for each cell (again, for full details see Laidler et al. (2006)). In practical terms, in order to run TFIT, we form a library of FITS files, each containing a single object, and a corresponding catalog of x-y positions and isophotal fluxes. These object images have been cut out from a high resolution image which has been first cataloged by a tool such as SExtractor (Bertin & Arnouts, 1996). A SExtractor run also produces a segmentation map that tells which pixels belong to which object. The local sky background is then subtracted from each cutout and each cutout is normalized to have a total flux of unity. Each FITS file is also produced with accurate WCS that precisely locates the image on the sky. Each cutout is then convolved with 55 a convolution kernel in order to transform the HR image to the LR image, producing a template. Nominally, the convolution kernel, also known as the PSF or the transfer kernel, is constructed using information from both low resolution and high resolution images. However, the transfer kernel can be based exclusively on the low resolution image if the high resolution image has sufficiently high resolution as to be treated perfect. For example, we were able to use the IRAC PSFs exclusively for the ACS-IRAC TFITing. In contrast, for the ACS-ISAAC TFITing we had to construct transfer kernels with both ACS and ISAAC PSF information folded in. Because the LR image is typically at a much coarser pixel resolution than the HR image, we rebin the convolved images to the LR pixelation. For cell construction, we use the LR image to determine the size of the cell. The cell has to be large enough to contain all the light produced by an object close to the cell’s center, but not much larger. We can then use the cells and object templates in them to run the fitting procedure against the LR image. TFIT produces a catalog of objects with scaled fluxes and corresponding errors. In addition, a number of diagnostic catalogs and images are produced, which can be used to ascertain the reliability of the TFIT products. A model collage can be subtracted from the real LR image to obtain a residual image (see Fig. 3.14), which can be examined for registration, background, and PSF issues. There are some subtleties based on the HR and LR bandpass differences (see Laidler et al. (2006)). Since the LR image often has astrometric properties (such as distortion) not captured by the WCS matrix, the collage is cross-checked against the LR image in zones. A set of new transfer kernels can then be created to incorporate any astrometric shifts necessary to produce better fits. This completes the process, however, many details, especially those regarding preparation, are omitted in this overview, we refer the reader to Laidler et al. (2006) for all the details regarding TFIT. 56 3.8.2 TFIT Diagnostics To ascertain the validity of the TFIT procedure as well as the resulting catalogs, we need to conduct a number of diagnostic and calibration procedures. Most of the diagnostic work is discussed in Laidler et al. (2006) so we refer the reader to that work for the full discussion. Here, we briefly present some of the TFIT diagnostics. One of the main advantages of using TFIT over SExtractor is its ability to recover reliable photometry in crowded fields. Fig. 5.8 in §5 shows the relative ability of SExtractor and TFIT to recover closely separated objects, whereas Fig. 3.15 shows the abilities of SExtractor and TFIT in assigning reliable photometric errors. These two figures demonstrate the advantage of using TFIT over SExtractor, as TFIT is able to de-blend sources and assign reliable errors where SExtractor fails. In §3.8.1 we showed a typical fitted image along with a corresponding residual map (Fig. 3.14). Much can be gleaned just from the residual map itself, and indeed that is where most of TFIT’s processing results were identified. Recall that the residual map is simply a fitted image subtracted from a LR image. If we look at the residual map we can identify a number of features. For instance, there are halos present in the residual image around many objects. These are a result of using imperfect PSF. Other features present themselves in the form of: minute positive detections around bright stars, dipole signatures around objects that are caused by imperfect registration, and annular residuals caused by transfer kernels which are too narrow. Also, we occasionally detect objects which are present only in the LR image. The dipole features caused by mis-registration were fixed by using a post-production registration step, where the fitted and LR images are divided into sections slightly larger than the cell size and then cross-correlated against each other. New local shifts are then obtained and propagated into the existing templates. Fig. 3.16 compares the residuals before and after the procedure was applied for the CDF-S IRAC4.5 epoch 1 image. We can see the improvement in residuals, where we see better centering on objects. However, the improvement in registration does not have a profound impact on derived photometry. Fig. 3.17 and Fig. 3.18 show the differences in photometry before 57 and after shifts. We can see that even though there is plenty of scatter, the differences are minimal. The minute positive features around bright stars are due to poor TFIT fits. The poor fits are most likely due to saturation or imperfections in the wings of the modeled transfer kernels. We have devised an imperfect solution to this problem by utilizing a correctly source-weighted RMS map. This procedure gives a lower weight to pixels belonging to the brighter objects and effectively reduces the anomalies. Finally, the transfer kernel issues can be eliminated by improving the kernel itself. This is done via TFIT simulations and additional calibration techniques described below. The resulting scaled flux is similar to an isophotal flux. We have tested that this so by comparing a ratio of IRAC TFIT-derived flux over ACS SExtractor-derived isophotal flux to a ratio of IRAC SExtractor-derived aperture flux over ACS SExtractor-derived aperture flux. In principle, if the TFIT-derived flux is indeed similar to an isophotal flux, the two ratios should be equal provided that the apertures used are large enough so that most of the flux from an object is retained and neighbor contamination is eliminated. To account for these two caveats we choose apertures of 2.82 and 9 %% in diameter for the ACS and IRAC data, respectively, and we choose isolated objects only. Fig. 3.19 shows what the behavior of the two ratios is as a function of the total IRAC magnitude. We can see that the ratio of the two ratios (quantity R in the figure) tends to unity, which confirms that the flux measured using isophotes correlates fairly well with the flux measured by TFIT. The actual R values turn out to be 1.01 ± 0.20, 1.02 ± 0.22, 1.07 ± 0.32, and 1.09 ± 0.34 for the CDF-S IRAC channels one through four, respectively. 58 5.8 8.0 3.6 4.5 250 N 200 150 100 50 250 N 200 150 100 50 -15 -10 -5 0 5 10 15 (tfit_flux_e2-tfit_flux_e1)/(sigma_e12) -15 -10 -5 0 5 10 15 (tfit_flux_e2-tfit_flux_e1)/(sigma_e12) Figure 3.5 Difference between epoch 1 and epoch 2 derived fluxes, normalized by the weighted epoch 1 epoch 2 flux error. Each panel shows this distribution for each IRAC channel. We see that there are not any major deviations between the two epochs for each of the channels. Only best objects, well-detected, objects were used for these plots. The black curves are gaussian with zero mean and unity sigma. In the two shorter wavelength channels, TFIT appears to underestimate the uncertainty, possibly due to imperfections of the PSF and image registration. 59 Figure 3.6 Color vs total magnitude for U-dropout galaxies. The UV-continuum rest-frame colors. 60 Figure 3.7 Color vs total magnitude for U-dropout galaxies. The Balmer-Break rest-frame colors. 61 Figure 3.8 Same as Fig. 3.6, except for B-dropout galaxies. 62 Figure 3.9 Same as Fig. 3.7, except for B-dropout galaxies. The color-magnitude trend seen here is due mostly to selection effects, where we are reaching limits in our IRAC depth at this redshift. 63 Figure 3.10 Same as Fig. 3.6, except for V-dropout galaxies. The use of ISAAC data that has not been processed through TFIT affects the number of recovered reliable photometry. 64 Figure 3.11 Same as Fig. 3.7, except for V-dropout galaxies. 65 Figure 3.12 Color selection in the data and fiducial semi-analytic model plane. The small black dots are all galaxies recovered from ACS catalogs, the green points refer to observed B-dropout galaxies, the blue points represent all galaxies from the fiducial model, and the yellow points refer to B-dropouts selected from the fiducial model (§2.3). 66 Figure 3.13 This shows a flow chart of how TFIT works 67 Figure 3.14 The left panel shows the simulated image for the CDF-S IRAC4.5 epoch 1 mosaic produced by TFIT. This image is then subtracted from the real mosaic to produce the residual image seen in the right panel. The bull-eye artifacts seen in the residual image are due to the use of an imperfect PSF. 68 Figure 3.15 TFIT vs SExtractor errors as a function of source separation. Blue corresponds to TFIT errors, while red corresponds to SExtractor-derived errors. 69 Figure 3.16 The left panel shows the residual image for the CDF-S IRAC 4.5 epoch 1 mosaic produced by TFIT, whereas the right panel shows the residual for the same image after positional corrections have been applied. 70 3.6 2000 N 1500 1000 500 -15 -10 -5 0 5 (tfit_flux_p2-tfit_flux_p1)/(sigma_p12) 10 15 Figure 3.17 This shows the normalized flux difference between pass two (post-shift) vs pass one (pre-shift) for the CDF-S IRAC 4.5 epoch 1 mosaic, for isolated sources. Though there is much scatter, the mean differences are small. The black curve is a gaussian with zero mean and unity sigma. 71 0.2 TFIT Mag (Pass2 - Pass1) 0.1 0.0 0.1 3.6 0.2 19 20 21 22 23 Mag_Auto Figure 3.18 This shows the difference in magnitude between the two passes vs the total magnitude for the CDF-S IRAC 4.5 epoch 1 mosaic, for isolated sources. The differences between the two passes are once again minimal. 72 2.5 2.0 R 1.5 1.0 0.5 0.0 -0.5 5.8 8.0 3.6 4.5 2.5 2.0 R 1.5 1.0 0.5 0.0 -0.5 19 20 21 22 23 19 Mag_Auto 20 21 22 23 Mag_Auto Figure 3.19 For each panel, we present the quantity R (see text) as a function of the IRAC total magnitude. The different IRAC channels are presented in each panel. The expectation is that the quantity R would have a value of unity, meaning that the ratio of TFIT to isophotal fluxes would be equivalent to the ratio of aperture fluxes. We can see that R is about unity and so the flux measured using isophotes correlates fairly well with the flux measured by TFIT. 73 Chapter 4 Model Exploration, Parameter Choices, & Diagnostics 4.1 Overview In order to get a handle on how the semi-analytic models behave as we vary the various parameters we have to explore how the models behave in both the photometric and physical plane. Not only will this analysis give us an idea of how strongly the various parameters behave, but also it will tell us which parameters to vary when doing our analysis, how much to vary them, and which diagnostics we should be looking at. In the following sections we go over our model exploration and then state our parameter choices as well the diagnostics that will be used for out fitting analysis. It is important to note here that this exercise is necessary not only for its educational reasons, but also for computational reasons. Constructing semi-analytic models is processor-intensive, so it is imperative to narrow the parameter space before attempting to analytically fit models to data. This becomes especially apparent when one considers the fact that we have to run multiple iterations of each model to obtain a sufficient number of points for our fitting analysis (see §6). We run a 74 grid of models based, to start with, on the fiducial model described in §2.3, individually varying each parameter while holding others constant. Each model is run down to the stellar mass limit of 107 M# , corresponding roughly to a magnitude limit of z850 ∼ 33. Besides computing photometry and physical properties such as star formation rates, we also independently compute the mean and variance of star formation rates over smoothed time bins of varying width using the star formation histories produced by the models such as those in Fig. 2.5. The complete grid of computed models can be seen in Table 4.1. The final choice of parameters for the fitting analysis can be seen in Table 4.2. Unlike Table 4.1 however, all of the parameters seen in Table 4.2 were run in all possible permutations. Whenever we refer to U-, B-, or V-dropouts, we mean that the model galaxies were processed through the same color selection criteria described in §3.7.2 before being evaluated, although it must be noted that the color selection criteria were applied on models that have not been processed through an observational scatter. As a check, we do verify though that the models do indeed have sensible redshift distributions as compared to simulations carried out in §5 and results stated in §3.7.2. 4.2 4.2.1 Model Exploration Dust Parameters We begin by studying the effect of varying the dust recipes. We study both the power-law and Charlot-Fall recipes. Fig. 4.1 and Fig. 4.2 show how varying τdust, 0 and keeping βdust constant affects the rest-frame UV-continuum and Balmer-break colors for B-dropout galaxies. We can see that varying τdust, 0 between values of 0.1 to 2.0 profoundly affects the rest-frame colors, changing the colors by several tenths of a magnitude. We see similar behavior for the U-, and V-dropouts. If we keep τdust, 0 constant but vary βdust instead, we only detect slight variation in the UV-continuum colors (see Fig. 4.3 and Fig. 4.4). Same type of behavior is observed for U-, and V-dropouts. This tells us that it makes sense to fix βdust to a constant value while at the same time adopt a coarse 75 Table 4.1. Grid of Parameter Choices Type Dust ··· Dust Recipe Power-Law ··· Charlot-Fall Parameters τdust, 0 0.1, 0.3, 0.5 τV, 0 0.1, 0.5, 1.0, 1.2, 1.5, 2.0 ··· µ ··· ··· ndust ··· Bursty SF ··· ··· ··· SNae Feedback ··· Dynamical Time ··· No Bulge ··· Bulge ··· Power-Law ··· 0.1, 0.5, 1.0, 1.2, 1.5, 2.0 βdust ··· Quiescent SF Values 0.05 - 20.0 0.5, 0.6, 0.7, 0.8, 0.9 τ∗0 1.5, 12.0 α∗ 2.5 '0burst 0.5 αburst 0.5 '0burst bulge 0.5 αburst bulge 1.5 '0SN 1.0 αrh 2.0 Select parameter choices displayed. To find all values for all other relevant parameters see §2 grid for the optical depth τdust, 0 parameter. This way we will get a good coverage of model behavior while focusing our analysis on a narrow range of dust paramters. In the case of Charlot-Fall dust recipe, we vary τV, 0 , µ, and ndust parameters. Fig. 4.5 and Fig. 4.8 show how varying parameters that control the optical depth affects the colors of B-dropout galaxies. We see that the Balmer-break colors are slightly redder for the case where we essentially saturate the optical depth parameters as opposed to the low-dust case, but the UV-continuum remains largely unchanged. Moreover, it is apparent that the colors produced by the Charlot-Fall recipe are much too red as compared to the colors of real Lyman-break galaxies found in §3.7.2. The power-law dust models produce reasonable colors on the other hand. Varying the slope parameter ndust does not improve things (see Fig. 4.7 and Fig. 4.8) substantially. Similar behavior is observed for both the U-, and the V-dropouts. Either the Charlot-Fall model does not adequately reproduce the colors of high-redshift galaxies or there 76 is something wrong with our implementation of that model. Because of the significant differences in the colors and the apparent lack of variation across the Charlot-Fall parameter grid, we exclude the Charlot-Fall models from our fitting analysis at this time, and instead concentrate our efforts on the power-law recipe. 4.2.2 Quiescent & Merger-Induced Star Formation Parameters In Fig. 4.9 and Fig. 4.10 we show the effects of maximizing and minimizing the star forma- tion rates on the colors of B-dropouts. We produce models where we maximize or minimize both the quiescent and merger-induced star formation together and independently by choosing proper parameter values. We can see that there is very little difference between the two color-magnitude plots when looking at galaxies brighter than z850 < 27. If we go deeper than our magnitude cutoff and look at quiescent and burst modes separately we begin to note differences. We observe that models with lower quiescent star formation activity display a higher proportion of red galaxies with redder Balmer-break colors. Accelerated quiescent star formation models exhibit bluer mean colors. The photometric differences between the extremes of the quiescent mode are quite apparent even down to our photometric limits. In contrast though, looking at burst mode recipes, we note subtler effects. We see that models with higher burstiness display slightly more scatter in the Balmer-break color distribution down to our magnitude limit. If we drop below our magnitude threshold we see much more significant differences. Models that have higher burst levels display a larger proportion of faint and blue objects than low-burst or no burst models. In general, the quiescent star formation modes display differences more readily down to our magnitude limit, whereas the various bursty modes mostly exhibit differences below our detection threshold even when we consider the extremes of burstiness. The only notable differences for the bursty modes down to our magnitude limit occur in the relative Balmer-break color scatter and they are most strongly controlled by the αburst parameters. In contrast, when we look at some of the physical attributes of the models like the statistics 77 Figure 4.1 Color-color plots of B-dropout galaxies taken from the fiducial model probing the UVcontinuum and the Balmer-break rest-frame colors. This shows colors from a model with low-dust (low τdust, 0 ) content. 78 of the star formation histories we see notable differences. Fig. 4.11 shows the normalized variance of smoothed star formation rates, smoothed over time bins of 10 Myrs, down to z850 ∼ 28, for all dropouts. We can see that the high star formation model exhibits more positive normalized variance values. This is due to the higher burst activity of the high star formation model. Interestingly, if we look at all galaxies we again clearly see the differences in the shapes of the distributions (see Fig. 4.12). The much broader and uniform distributions exhibited by the high star formation model are due again to a population of bursting galaxies. Another quantity we can look at is the distribution of smoothed star formation rates. Fig. 4.13 shows the distribution of star formation rates, smoothed over 10 Myr time bins. While differences were quite clear when looking at normalized variances, here the distinctions are more subtle. We have also tried different smoothing bins as well as different magnitude cuts, however, the apparent lack of distinction remains. Looking at the photometry and the star formation histories gives us a good idea of how the models behave when pushed to their limits. If we look at certain star formation history statistics, such as the normalized variance, we can see clear differences between high and low star formation models. In contrast, for other statistical quantities, such as the distribution of smoothed star formation rates, the differences between the two models are not that clear. The situation does not change when looking at different smoothing bins and magnitude cuts. In the photometric plane and down to our magnitude limit, the color-magnitude differences between the various bursty star formation models are seen in the slight width differences in the color distributions. Below our magnitude threshold we note more significant differences, where we see a higher ratio of bluer galaxies in the very bursty model. It is difficult to ascertain just how well the different bursty star formation models will be distinguished when confronted with observational scatter and data. We explored different color-magnitude combinations to see if we could delineate between the different burst modes with more effect, but we have not been able to find more useful diagnostics. Through our exploratory analysis we see that it may be difficult to get a handle on parameters that control the relative burstiness of the models. While the physical diagnostics offer some 79 insight, the photometric differences are small down to our magnitude limit. In light of these facts, and keeping in mind the behavior of the star formation scaling laws described in §2 we pick parameter values seen in Table 4.2. In the case of quiescent star formation we choose two well-separated time-scale τ∗0 parameter values of 1.5 and 12.0 so as to provide the widest separation in realistic model behavior. For the power index α∗ parameter we choose a set of values ranging from 0.0 to 4.5; where the α∗ = 0.0 case corresponds to the case where the quiescent star formation is independent of the circular velocity of the disk (see §2.2.6). Fig. 4.16 and Fig. 4.17 show how the Balmer-break and UV-continuum colors vary for two models with quite different α∗ parameter choices. In the case of merger-induced star formation we largely choose Cox et al. values (such as the burst threshold, time-scales, and default efficiencies), although we allow the power indices that control the level of burst efficiency to vary, using αburst of 0.5, 1.0, 1.5, and αburst bulge of 1.0, 1.5 for the case where a bulge is present (see §2.2.5). Based on our preliminary work and considering our data limitations we feel that these parameters will give us the most leverage. 4.2.3 Supernovae Feedback We decided to see what happens when we vary the supernovae feedback recipes. In Fig. 4.14 and Fig. 4.15 we show two different feedback recipes, the Martin-Heckman and the power-law recipes, for B-dropouts (recall that we neglect the disk-halo model as it is outdated). We can see that there is very little difference in the colors between the two models. Recall, that the Martin-Heckman recipe differs from the power-law recipe only in the sense that the latter depends on the circular velocity. In fact, running the power-law recipe with αrh set to zero yields exactly the same results as running the model with the Martin-Heckman implementation. We decided to look at several values of αrh to see if we can modify the behavior of the model. However, we did not see any notable changes in photometry, which is not surprising given that the Martin-Heckman and power-law with αrh = 2.0 shows so little difference. We looked at other dropouts and color combinations, but we did not see any significant differences between the models in the photometric plane. Perhaps our photometric 80 diagnostics are not sensitive enough to distinguish among the supernovae feedback power-law models that have different αrh values. Because the differences between the models are minute, we decided to not vary these parameters, but rather keep the power-law fixed to the αrh = 2.0 value. 4.3 Final Model Parameters & Model Run Attributes We explicitly state all the parameter choices in Table 4.2. Again, these parameters were computed in all possible permutations (resulting in 144 unique models). Even though we do not vary the supernovae feedback recipes, we state them as well. All of the remaining values pertinent to the various recipes are set to the values found in §2. Each model run for the fitting analysis spans a redshift range of 2 < z < 6, sufficient for our color selection completeness (see §3.7.2), but narrow enough to minimize processing time. We run each model with two iterations down to the magnitude limit of z850 < 28. This gives us sufficient number of galaxies for the construction of density functions (see §6). For each model we compute all of the relevant photometry and we propagate all of the relevant physical properties. We also compute star formation history statistics, independently from the model as was the case in §4.2.2. Each model takes approximately 14 hours of processor time. In addition to these models, we also produce models using the same characteristics and parameter choices, but using a stellar mass cut of 107 M# , instead of a z850 cut. These models are identical to the previous ones and they will be used to provide information below the z850 < 28 threshold. It was necessary to run two separate model runs for each parameter set due to computational considerations. Finally, based on our experimentation, we decided on using the UV-continuum and Balmer-break colors and the UV-magnitude as diagnostics for our fitting analysis. The choices of using UV-continuum and Balmer-break colors stems from our desire to explore the dust content and the star formation rates of model galaxies. The UV-continuum colors probe the slope of the UV continuum, which is believed to be primarily an indicator of internal dust content in young stellar populations (e.g. Meurer, Heckman, & Calzetti 1999). The Balmer-break colors tend to probe the 81 Table 4.2. Final Parameter Choices Type Dust ··· Quiescent SF ··· Bursty SF ··· ··· ··· SNae Feedback ··· Recipe Power-Law ··· Dynamical Time ··· No Bulge ··· Bulge ··· Power-Law ··· Parameters τdust, 0 βdust Values 0.5, 1.0, 1.5 0.3 τ∗0 1.5, 12.0 α∗ 0.0, 0.5, 1.5, 2.5, 3.5, 4.5 '0burst 0.5 αburst 0.5, 1.0, 1.5 '0burst bulge 0.5 αburst bulge 1.0, 1.5 '0SN 1.0 αrh 2.0 Select parameter choices displayed. To find all values for all other relevant parameters see §2 stellar ages and masses. Although these color combinations do not exclusively probe just dust or stellar ages, due to the effects of dust-age-metallicity degeneracy, historically, they have proved to approximately work in such a manner (Somerville, Primack, & Faber 2001; Idzi et al. 2004; Papovich, Dickinson, & Ferguson 2001). The final choices for the U-dropouts (restated in §6) are the V606 - i775 vs i775 and V606 - IRAC 3.6 vs V606 color-magnitude diagnostics. The final choices for the B-dropouts (restated in §6) are the i775 - z850 vs z850 and z850 - IRAC 4.5 vs z850 color-magnitude diagnostics. These diagnostics along with the limits used and approximate rest-frame values are stated in Table 4.3. These combinations provided us with the best combination of probing the relevant colors and magnitudes and retaining close rest-frame correspondence between the two dropout samples. 82 Table 4.3. Diagnostic Choices Dropouts U ··· U ··· B ··· B ··· Diagnostic UV-continuum ··· Balmer-break ··· UV-continuum ··· Balmer-break ··· Selection V606 - i775 i775 V606 - IRAC 3.6 V606 i775 - z850 z850 z850 - IRAC 4.5 z850 83 Limits Rest-frame Values (Å) -0.5 - 1.5 1515 - 1938 20 - 27 1938 -1.5 - 4.5 1515 - 9000 20 - 27 1515 -0.5 - 1.5 1550 - 1700 20 - 27 1700 -1.5 - 4.5 1700 - 9000 20 - 27 1700 Figure 4.2 Same as in Fig. 4.1 but for a model with high-dust (high τdust, 0 ) content. Going above τdust, 0 of 1.5 does not change colors – indicating saturation. 84 Figure 4.3 Color-color plots of B-dropout galaxies taken from the fiducial model probing the UVcontinuum and the Balmer-break rest-frame colors. This shows colors for a model that uses low βdust . 85 Figure 4.4 Same as in Fig. 4.3 except for a model that uses high βdust . 86 Figure 4.5 Color-color plots of B-dropout galaxies taken from the fiducial model probing the UVcontinuum and the Balmer-break rest-frame colors. This shows a model with a low dust content. 87 Figure 4.6 Same as in Fig. 4.5 except for a model with a high dust content. The variation in the UVcontinuum colors is very slight. More importantly though it is quickly apparent that the Charlot-Fall colors are much too red as compared to the real Lyman-break galaxies found in §3.7.2. 88 Figure 4.7 Color-color plots of B-dropout galaxies taken from the fiducial model probing the UVcontinuum and the Balmer-break rest-frame colors. This shows a model with a low ndust . 89 Figure 4.8 Same as in Fig. 4.7 except for a model with a high ndust . The colors are still much too red as compared to our data, however the low-slope ndust value does produce better UV-continuum results. 90 Figure 4.9 Color-magnitude plots of B-dropout galaxies taken from the fiducial model probing the the Balmer-break rest-frame colors. This shows a model with high combined star formation. 91 Figure 4.10 Same as in Fig. 4.9 except for a model with low combined star formation. We can see very little difference between the low and high star formation color-magnitude plots, except that the high star formation plot exhibits broader colors when looking at galaxies brighter than z850 < 27. 92 High SFR z̄3 z̄4 z̄5 Low SFR -0.5 0.0 0.5 -0.5 Log[7/<sfr>7] 0.0 0.5 Log[7/<sfr>7] Figure 4.11 Here we can see the difference between the high and low star formation models when looking at the variance of smoothed star formation rates, smoothed over time bins of 10 Myrs, down to z850 ∼ 28, for all dropouts. We can see that the high star formation model exhibits more positive variance values. This is due to the high burst activity of the high star formation model. 93 High SFR z̄3 z̄4 z̄5 Low SFR -0.5 0.0 0.5 -0.5 Log[7/<sfr>7] 0.0 0.5 Log[7/<sfr>7] Figure 4.12 Here we can see the difference between the high and low star formation models when looking at the variance of smoothed star formation rates, smoothed over time bins of 10 Myrs, for all galaxies, and for all dropouts. We can see that the high star formation model exhibits broader distributions. This is due to a population of bursting galaxies. 94 High SFR z̄3 z̄4 z̄5 Low SFR -6 -4 -2 0 2 -6 Log[sfr7] -4 -2 0 2 Log[sfr7] Figure 4.13 Here we see very little difference between the high and low star formation models. Nevertheless, we do see that in the case of high SFR model, the bimodal distribution in SFR values, smoothed over 10 Myr bins, remains, while in the case of low SFR model, the bimodal distribution dissolves. 95 Figure 4.14 Martin-Heckman feedback model. Essentially, the power-law model with αrh = 0.0. 96 Figure 4.15 We see very little difference between the Martin-Heckman and the power-law feedback models. Changing the power index αrh makes very little difference. The power-law model shown uses αrh = 2.0. 97 U-dropout Balmer-break Colors -1 0 1 2 3 V - 3.6 Figure 4.16 Here we can see the difference in Balmer-break colors for two very different model runs, where we varied the parameters. The top panel shows a model with α∗ = 0.0, whereas the bottom panel shows a model with α∗ = 4.5. These models did not have any observational scatter added to them. 98 U-dropout UV-continuum Colors 0 0.5 1 V-i Figure 4.17 Same as in Fig. 4.16, but for UV-continuum colors. We can see that the difference in colors is not as stark as for the Balmer-break colors, however, in this case we have not varied the dust parameters and so we did not expect much variation in the UV-continuum colors. 99 Chapter 5 Simulations and Observational Scatter 5.1 ACS Simulations The Monte-Carlo ACS SExtractor simulations are based on synthetic Lyman-break galaxies distributed over a wide redshift range (2 < z < 8) with assumed distribution functions of UV luminosity, SED, morphology, and size, adjusted to match the colors of observed dropouts observed at the respective redshifts. This technique has been successfully used before by Sawicki & Thompson (2006), and others. Here we give a brief description of the procedure. We construct the spectral energy distributions (SEDs) of star forming galaxies using the (Bruzual & Charlot 1993) spectral synthesis library, with the Salpeter initial mass function and the solar metallicity with the age of 100 Myr. These SEDs are modeled such that they adequately represent observed galaxies (Sawicki & Yee 1998; Shapley et al. 2001). Each galaxy is first assigned a random redshift in the range 2 < z < 6, then dust attanuation is applied using a Calzetti (1997) extinction curve together with a normal distribution with median E(B-V) = 0.15. Line blanketing 100 ACS Simulation: B-dropouts N (x1000) 2 1 2.5 3 3.5 4 4.5 Redshift Figure 5.1 Redshift distributions for B-dropout galaxies taken from ACS simulations. due to intergalactic neutral hydrogen is then computed using the prescription of (Madau et al. 1996). Once reddened SEDs are constructed, filters are used to obtain synthetic colors and photometry. Artificial galaxies are then constructed using IRAF artdata routines. These fake galaxies are then placed into GOODS mosaics using variable morphology with random orientations and inclinations and pre-computed magnitude distributions. Profile-wise, the simulated galaxies are split evenly between disks (exponential surface brightness profiles) and spheroids (r1/4 -law surface brightness profile). Spheroidal galaxies are assumed to be oblate and optically thin with an intrinsic axial ratio distribution that is uniform in the range 0.3 < b/a < 0.9. Disk galaxies are modeled as optically thin oblate spheroids with an intrinsic axial ratio of b/a = 0.05. Each galaxy is assigned a radius from a log-normal radial distribution. The simulated galaxies are then detected and color selected 101 Semi-Analytic Model: B-dropouts 8 N (x100) 6 4 2 3.5 4 4.5 Redshift Figure 5.2 Redshift distributions for B-dropout galaxies taken from the fiducial semi-analytic model. using the same criteria as used in the real sample construction. This allows us to ascertain such systematics like detection bias, color bias, etc. Of course with such simulations, one must be aware of possible crowding issues. To this extent multiple trials were executed to find the best number of fake galaxies. The final simulations used 200 simulated galaxies at a time, with 200 iterations per image. To obtain enough simulated data points for the construction of the scatter density functions (see §6) we repeated the procedure eight times. The detection and photometry was done using SExtractor (akin to what was done for real data). Master catalogs are then generated that collate all of the input and output magnitudes, along with whether the simulated objects were recovered or not. With fully-formed catalogs in hand, redshift distribution functions were constructed for each sample to test the efficiency of color selec- 102 ACS Simulation: Input Colors 4 N (x10000) 3 2 1 0 0.5 1 i_iso - z_iso Figure 5.3 Input i775 minus z850 colors for the simulated B-dropouts. tion criteria (see §3.7.2 discussion). The final sample had roughly 320 thousand simulated galaxies. Fig. 5.1 and Fig. 5.2 shows the distribution of B-dropouts calculated from the simulations using our color selection criteria, as well as B-dropouts as computed from the fiducial model run. We can see how well these distributions overlap. Fig. 5.3 and Fig. 5.4 shows the input and output i775 - z850 colors and Fig. 5.5 and Fig. 5.6 shows the input and output V606 - i775 colors. In §6, we show how these input-output distributions translate to scatter density functions. Finally, in Fig. 5.7 we show the E(B-V) distribution for the B-dropout galaxies extracted from the simulations. 103 ACS Simulation: Measured Colors 4 N (x10000) 3 2 1 0 0.5 1 i_iso - z_iso Figure 5.4 Output i775 minus z850 colors for the simulated B-dropouts. 5.2 ACS–IRAC TFIT Simulations To validate the results from TFIT and to procure scatter density functions we have run a series of purely synthetic simulations using artificial galaxies for which we know the input fluxes. Unlike in the ACS simulations, we do not include any of the real data. Ideally, we should, but computationally this is not feasible. TFIT is a very processor intensive software package, using real data mosaics would significantly extend processing time. In addition, crowding would be a much more serious issue. For these reasons and others we choose a purely synthetic approach. For these tests we use simulated ACS V606 and z850 data for the high-resolution images, and simulated IRAC 3.6 and 4.5 data for the low-resolution image. We randomly generate positions, magnitudes, and sizes for these galaxies for the high-resolution image. The distributions that we use for the input 104 ACS Simulation: Input Colors 4 N (x10000) 3 2 1 0 0.5 1 V_iso - i_iso Figure 5.5 Input V606 minus i775 colors for the simulated B-dropouts. sizes are selected from a log-normal radial distribution and the magnitude distributions are based on the same distributions as in §5.1. We select an even mix of spiral and elliptical galaxies. The magnitudes are then transformed based on a gaussian distributions for the V606 - IRAC 3.6 and z850 - 4.5 colors, with µ = 1.7 and σ = 1.5, and µ = 1.1 and σ = 1.5 (respectively), chosen to approximate the observed properties of the ACS and IRAC images. We used the IRAF task artdata.mkobjects to generate two high-resolution images containing the simulated objects: one with the simulated ACS magnitudes and one with the simulated IRAC magnitudes. The latter image is then convolved (iraf.fconvolve) with an IRAC PSF and re-sampled (iraf.blkavg) to match the IRAC pixel sampling. The resultant noiseless images are added (iraf.imcalc) to background images generated using iraf.mknoise to simulate the noise parameters of the two instruments. The noise (RMS) 105 ACS Simulation: Measured Colors 4 N (x10000) 3 2 1 0 0.5 1 V_iso - i_iso Figure 5.6 Output V606 minus i775 colors for the simulated B-dropouts. values are derived from the real data mosaic weight maps. Having generated these test images, we proceed through the usual TFIT pipeline (§3.8): cataloging the high-resolution image, making cutouts, convolving, culling, fitting, and selecting the best answer for each object. Then, we use the initial input list to locate the simulated objects (based on cataloged x,y position), and examine the results. For simplicity, the initial TFIT simulations were performed using a single pair of objects, of equal magnitude and varying separation. Those results were analyzed and compared to SExtractor (Fig. 5.8). The nearest-neighbor distances for all objects in the GOODS CDF-S field were computed and it was found that only a few percent of the objects were sufficiently isolated for optimal measurement by SExtractor in the IRAC field. For approximately 20 percent of the objects, 106 ACS Simulation N (x1000) 3 2 1 -0.2 0 0.2 0.4 0.6 0.8 E(B-V) Figure 5.7 E(B-V) distribution for the simulated B-dropouts. the TFIT measurements would be optimal, while the SExtractor measurements would be degraded. SExtractor photometry for the remaining 78 percent of the objects would be severely compromised by deblending failures, while TFIT measurements are only degraded. The case is worse for the UDF observations, where barely 1 percent of the sources are isolated, and 95 percent are severely compromised for SExtractor. In all cases, the sense of the error is to overestimate the true flux, which in our case means over-estimating the true MIR fluxes. While validating TFIT is important, that task is covered by Laidler et al. (2006) and here we can only spend so much time discussing the validity. What is more pertinent is to generate largescale simulations of ACS-IRAC catalogs so that we can produce the scatter density functions (see §6). To assess performance in more realistic conditions, we ran simulations that mimic the number 107 Figure 5.8 Cumulative recovery rates as a function of source separation in the CDFS for simulated SExtractor and TFIT catalogs. Green refers to results that are as good as for isolated cases for both SExtractor and TFIT, yellow corresponds to cases where SExtractor produced degraded results and TFIT gives results as good as for isolated sources, whereas red corresponds to cases where SExtractor failed to de-blend and TFIT produced degraded results. density and color characteristics of the V606 - IRAC 3.6 and z850 - IRAC 4.5 data. The simulations follow the same procedure as described in the previous section, with the addition of a few extra parameters. We add 220 objects to a 1.7 square arcmin field, with randomly assigned magnitudes based on the distributions used in §5.1. A color term, drawn from a Gaussian distribution based on the numbers stated earlier, is added to each object before the simulated IRAC image is created. The results are then collated and master catalogs are produced with the input and output magnitudes 108 Figure 5.9 IRAC 3.6 PSF used in the simulations. and whether the simulated galaxies were recovered or not. In all, 200 iterations with 220 objects per image were generated at each run. Together eight simulations were run, yielding roughly 320 thousand objects for each image pair. Below we post figures that show the effectiveness of the simulations as well as the input data. Fig. 5.9 and Fig. 5.14 show the input PSF used to convolve the high-resolution cutouts. Fig. 5.10 and Fig. 5.15 show the resulting fake and real images for the ACS and IRAC data. Finally, Fig. 5.11 shows the input V606 and z850 magnitude distributions, and Fig. 5.12, Fig. 5.13, Fig. 5.16, and Fig. 5.17 show the input and output colors for the pair of images used. The scatter density functions are shown in §6. 109 Figure 5.10 Simulated and actual V606 and IRAC 3.6 mosaics. From top-left, clockwise, we have the fake IRAC 3.6, real IRAC 3.6, real V606 and fake V606 . We can see that even though the simulations are purely synthetic, the source density and character are well reproduced in the simulations. 110 V 606 500 300 100 i775 500 300 100 z850 500 300 100 18 20 22 24 Figure 5.11 Input magnitude distributions based on ACS data. 111 26 28 TFIT IRAC Simulation: Input Colors N (x10000) 2 1 -2 -1 0 1 2 v_input - 3.6_input Figure 5.12 Input V606 minus IRAC 3.6 colors. 112 3 4 5 TFIT IRAC Simulation: Measured Colors N (x10000) 2 1 -2 -1 0 1 2 v_iso - 3.6_tfit Figure 5.13 Output V606 minus IRAC 3.6 colors. 113 3 4 5 Figure 5.14 IRAC 4.5 PSF used in the simulations. 114 Figure 5.15 Simulated and actual V606 and IRAC 4.5 mosaics. From top-left, clockwise, we have the fake IRAC 4.5, real IRAC 4.5, real z850 and fake z850 . We can see that even though the simulations are purely synthetic, the source density and character are well reproduced in the simulations. 115 Figure 5.16 Input z850 minus IRAC 4.5 colors. 116 Figure 5.17 Output z850 minus IRAC 4.5 colors. 117 Chapter 6 Methodology 6.1 Overview In this chapter we describe the full machinery that is needed to accomplish the likelihood analysis method used in this project. We go over each component of the analysis and refer the reader to other chapters and section where needed. To get an overview of our analysis method it is perhaps easiest to start with a view of a flow chart (Fig. 6.1) that shows the various components of the analysis and how these components interact with one another. From a computational point of view the goal of the project is to compare semi-analytic models to real Lyman-break galaxies using photometric information only. We saw in Idzi et al. (2004) how one can make significant progress in comparing models to data by using strictly qualitative analysis, or simple quantitative techniques. However, a more robust statistical analysis becomes a far more powerful tool in delineating which models work, since a more rigorous technique can provide us with more robust results along with confidence intervals, which in turn provides more insight into the physics that we are trying to probe. 118 Figure 6.1 Here we see the flow of the likelihood analysis used in this project. 6.2 Data First, the data used for the analysis is composed of the U-, and B-dropout samples described in §3.7.2. We refer the reader to that section for the details on the data samples. Briefly though, the data for the likelihood analysis is composed of 569 and 275 sources taken from the CDF-S Uand B-dropout samples. Each source has SExtractor-derived fluxes and errors for the V606 , i775 , z850 data, and TFIT-derived fluxes and errors for the IRAC 3.6 and 4.5 data. The IRAC data is either composed of single or dual-epoch data depending on coverage and quality of the epoch data. In addition, these sources already have pre-applied flag and signal-to-noise cuts as defined in §3.7.2. 119 6.3 Models In §2 we described in great detail the semi-analytic code used in this work, and in §4 we described and justified the choice of input parameters and diagnostics used. We also elaborated on how each model set was run. Here we simply restate few items and describe how we formatted the models to work in the context of the analysis we adopted. To begin with, recall that we ran a grid of 144 models with the input parameter choices given in Table 4.2. Each model run was conducted in a survey mode spanning the GOODS area, in the redshift range of 2 < z < 6 to fully capture the Lyman-break samples used in this work . For each set of model parameters, we ran three iterations in total, two iterations in a magnitude cut-off mode where only galaxies brighter than z850 ∼ 28 were output, and one iteration in a stellar-mass limit cut-off mode where galaxies with M∗ > 107 M# were kept. The magnitude-limited model runs were then used to construct model density functions needed for the statistical analysis, whereas the mass-limited model run was used as a supplemental catalog that contained properties of galaxies fainter than z850 ∼ 28, all the way down to galaxies with total stellar masses of M∗ ∼ 107 M# (roughly z850 ∼ 33). This rather inelegant procedure was necessary since running multiple iterations of the models in the mass-limited mode would have produced very large output files that would prove difficult to handle for further analysis. Therefore, we decided to simply keep the larger mass-limited files separate from the magnitude-limited ones used for the creation of density kernels. It is important to remember however that the mass and magnitude cut-offs strictly apply to the output data and so the underlying model runs were statistically the same, drawn from the same model parameters. As mentioned, we use the magnitude-limited models to construct density functions. Even though we limit the models to a z850 < 28 depth, this is sufficient for the analysis since at this ,S∼ 3). In fact, in z850 magnitude our real Lyman-break samples becomes very incomplete ( N 850 ,S∼ 5). The our analysis we don’t probe models with magnitudes fainter than z850 > 27 ( N 850 dual-iteration for the model run is necessary to obtain sufficient number of artificial Lyman-break 120 Table 6.1. Diagnostic Limits & Resolution Dropouts U ··· U ··· B ··· B ··· Diagnostic UV-continuum ··· Balmer-break ··· UV-continuum ··· Balmer-break ··· Selection V606 - i775 i775 V606 - IRAC 3.6 V606 i775 - z850 z850 z850 - IRAC 4.5 z850 Limits Bins Resolution -0.5 - 1.5 200 0.01 20 - 27 200 0.035 -1.5 - 4.5 200 0.03 20 - 27 200 0.035 -0.5 - 1.5 200 0.01 20 - 27 200 0.035 -1.5 - 4.5 200 0.03 20 - 27 200 0.035 galaxies for the construction of our density functions. We require a sample of, at a minimum, ∼ 5000 galaxies to construct robust density functions with the limits and bin choices we adopt. Such large number is necessary since we require a fine resolution in both the magnitude and color space. We construct density kernels that are 200 × 200 bins on each side, which in the case of the B-dropouts UV-continuum diagnostic translates to a resolution of 0.035 in magnitude space and 0.01 in color space, where the limits are: -0.5 < i775 -z850 < 1.5 and 20 < z850 < 27. To sufficiently populate such fine resolution and to avoid falling victim to low-number statistics, we require the ∼ 5000 sample limit. We refer the reader to Tables 4.3 and 6.1 for the diagnostic limits and resolution information. For each model we then construct model functions that are used for further analysis. We construct these density functions for each dropout-diagnostic combinations, which means we construct four separate templates for each model (UV- and Balmer-break diagnostics for U- and Bdropouts). We produces the dropouts samples by applying the same color Lyman-break selection criteria stated in §3.7.2, so that the model and data galaxies are selected in a uniform manner. Once the samples are generated and they have sufficient number of sources we proceed to construct the actual model density functions. This is accomplished by using a kernel-based probability density estimator code KPDFadapt (see Silverman (1986) for the mathematical background) to construct a 121 smooth estimate of the density from the discreet data that are output from a semi-analytic model run (see Fig. 6.2-6.5 for density function examples). Each cloud of model points consists only of those that fall within the given color-magnitude limits. Once smoothed, the model is normalized by the integral of the binned 2-D array. Once we generate one set of model density functions we repeat this same procedure for the remainder of the models. Since this is a time-consuming process we generate the density kernels once and save them as FITS files. 6.4 Observational Scatter The next step involves adding an observational scatter to the model density functions. Recall, that so far we have not added any scatter to the models. We simply took the generated models, applied color-selection criteria and produced the model density functions. So now we have to generate observational scatter functions that will take the input model magnitudes and colors and in effect ’translate’ that information to include the observational scatter that emulates the behavior of our real data. We generate these scatter functions using catalogs generated by the Monte-Carlo simulations described in §5. We use the same kernel-based code KPDFadapt as a foundation to generate the scatter kernels. For each simulated catalog we take the input and output magnitudes and the recovery information and translate that information into a series of 2-D scatter density functions. We construct an 8 × 8 matrix of density kernels in the color-magnitude plane for each diagnostic. For example, for the U-dropout UV-continuum V606 - i775 vs i775 diagnostic, we construct 64 kernels each of magnitude bin width of 1.75 and color bin width of 0.5, centered on input magnitude and color information. Fig. 6.6-6.9 show a sample of coarser (3 × 3) kernel matrices for all of the diagnostics. Note in the kernel figures, how the kernels degrade as we move to very red and very faint bins. This is a behavior we expect from observed data. With the scatter density kernels produced, we now convolve (see Eq. 6.1) the (normalized) models density functions (fm ) by the scatter density functions (fs ) for each diagnostic to produce the scattered model density 122 functions (fsm ). Fig. 6.11 shows sample raw model density functions and scattered model density functions. fsm = fm × fs 6.5 (6.1) Likelihood Analysis With the scatter properly folded into the model density functions we are now ready to compute log likelihood values using data points from §6.2 and the observationally-scattered models found in §6.3 and §6.4. For each Lyman-break and diagnostic combination, we take the data and construct color-magnitude arrays, masked over pre-specified limits, and put on the same grid as the models. We compute the log likelihood values for each model by first normalizing each model with an integral of the model density and the number of data points, then taking the product of the data and the log of the normalized model, and finally taking the integral of the result. This gives us the total log likelihood value for the tested model. We can capture this process in the following relation: log L = 2 D × log fsm (6.2) where log L designates the log likelihood, fsm is the (normalized) scattered model density function, and D designates the data. As stated, we compute log likelihood values for each model set, using the two dropout samples and the UV-continuum and Balmer-break diagnostics. We can then derive the best-fit model for each diagnostic and dropout sample, as well as the best-fit model for combinations of diagnostics and dropout samples. In order to assign confidence intervals for the best-fit models and to test the stability of those fits we generate Monte-Carlo realization of the fits. This is accomplished in three separate ways. First, for each real dropout sample, we boot-strap the photometric errors. 123 The observed galaxy fluxes are assumed to have a gaussian distribution with the mean flux equal to the observed flux value and σ equal to the flux error. The flux in each filter for each galaxy is replaced by a value drawn at random from this distribution. The log likelihood value for the model with the relative maximum log likelihood is re-calculated. This procedure is repeated 500 times to determine the 68%, 95% and 99.9% confidence intervals on the best-fit log likelihood value. The 68%, 95%, and 99.9% confidence interval values on the best-fitting model log likelihood value are compared to original grid of log likelihood values for all tested models. Models with likelihood values less than the 99.9% confidence interval value can be ruled out, while models with likelihood values greater than the 68% confidence interval cannot be distinguished from the model with the relative maximum likelihood. This tells us which model parameters are best-fit and which can be ruled out. In the second procedure, we do something similar, but instead of drawing from the data, we draw random points from the best-fit model. We use the best-fit scattered model density function and we draw, at random, points from that distribution. Effectively re-rebinning the color-magnitude information at each step. We then reconstruct a new scattered model density function and we re-compute the log likelihood value. We repeat this process 500 times and once again construct confidence intervals and compare those results to the results from the first procedure and the original likelihood values. While the first procedure allows us to study the stability of the results against the photometric errors in the data, the second procedure allows us to to study the variability of the model density functions of the best-fit models. In the third, and final procedure, we repeat the second procedure, but for all models. This gives us new log likelihood values for each model. We repeat this procedure 100 times, and rank the results to test the stability of the analysis across all models. These three procedures allow us to assign confidence intervals and test the stability of our analysis. In turn this allows us to state which model parameters work and which can be excluded based on our procedure and the available data. 124 Figure 6.2 A sample model density function (kernel) for a U-dropout model sample. The vertical axis corresponds to -0.5 < V606 -i775 < 1.5 and the horizontal axis corresponds to 20 < i775 < 27 125 Figure 6.3 A sample model density function (kernel) for a B-dropout model sample. The vertical axis corresponds to -0.5 < i775 -z850 < 1.5 and the horizontal axis corresponds to 20 < z850 < 27 126 Figure 6.4 A sample model density function (kernel) for a U-dropout model sample. The vertical axis corresponds to -1.5 < V606 - IRAC 3.6 < 4.5 and the horizontal axis corresponds to 20 < V606 < 27 127 Figure 6.5 A sample model density function (kernel) for a B-dropout model sample. The vertical axis corresponds to -1.5 < z850 - IRAC 4.5 < 4.5 and the horizontal axis corresponds to 20 < z850 < 27 128 Figure 6.6 A grid of scatter density functions for the V606 - i775 vs i775 diagnostics. Note the degradation in kernels as we move to very red and very faint bins. 129 Figure 6.7 A grid of scatter density functions for the i775 - z850 vs z850 diagnostics. Note the degradation in kernels as we move to very red and very faint bins. 130 Figure 6.8 A grid of scatter density functions for the V606 - IRAC 3.6 vs V606 diagnostics. Note the degradation in kernels as we move to very red and very faint bins. 131 Figure 6.9 A grid of scatter density functions for the z850 - IRAC 4.5 vs z850 diagnostics. Note the degradation in kernels as we move to very red and very faint bins. 132 1.5 1.0 0.5 0.0 -0.5 20 21 22 23 24 25 26 27 21 22 23 24 25 26 27 1.5 1.0 0.5 0.0 -0.5 20 Figure 6.10 U-dropout V606 - i775 vs i775 for model density (top panel) and observationally scattered model density (bottom panel). 133 Figure 6.11 The left panel shows the raw model density function, whereas the right panel shows the model density function convolved with the matrix of computed scatter functions. We can see the effect of applying observational scatter to the raw models. 134 Chapter 7 Results & Discussion 7.1 Best-fit Model(s) After the analysis carried out in §6 we collated all of the results for each of the dropout samples and diagnostics. In Table 7.1 we list the best-fit model for each of the dropout-diagnostic combinations. We can see that each dropout sample favors only one model. This is interesting as we have not forced any a priori arguments on the models. The diagnostics used for the two dropout samples could have favored entirely different models. We see however that only one model is favored Table 7.1. Best-fit Models Dropouts Diagnostic Model τ∗0 α∗ αburst αburst bulge τdust, 0 U UV-continuum 93 12.0 0.0 1.5 1.5 1.5 U Balmer-break 93 12.0 0.0 1.5 1.5 1.5 B UV-continuum 237 12.0 0.0 1.0 1.0 1.5 B Balmer-break 237 12.0 0.0 1.0 1.0 1.5 Select parameter choices displayed. To find all values for all other relevant parameters see §2 135 Table 7.2. Models Within the 68% (in bold) & 99.9% Confidence Intervals. log L τ∗0 α∗ αburst αburst bulge τdust, 0 93 -9963.45 12.0 0.0 1.5 1.5 1.5 75 -9722.25 12.0 0.0 0.5 1.5 1.5 219 -9689.77 12.0 0.0 1.0 1.5 1.5 237 -9685.66 12.0 0.0 1.0 1.0 1.5 147 -9548.18 12.0 0.5 1.0 1.5 1.5 165 -9538.21 12.0 0.5 1.0 1.0 1.5 21 -9535.23 12.0 0.5 1.5 1.5 1.5 3 -9526.60 12.0 0.5 0.5 1.5 1.5 Model Likelihood values are the total likelihoods taken across all samplediagnostic combinations. Select parameter choices displayed. To find all values for all other relevant parameters see §2 Table 7.3. Best-fit Models (Refit) Model τ∗0 α∗ αburst αburst bulge τdust, 0 75 12.0 0.0 0.5 1.5 1.5 93 12.0 0.0 1.5 1.5 1.5 237 12.0 0.0 1.0 1.0 1.5 219 12.0 0.0 1.0 1.5 1.5 Select parameter choices displayed. To find all values for all other relevant parameters see §2 for each dropout sample, and moreover, only two, very similar models, describe all redshift slices and color diagnostics. However, this alone does not provide any substantive insight since we lack information on the relative confidence of the fits. As per discussion in §6.5 we carried out three separate Monte-Carlo tests. Drawing random data sets and re-fitting those to the best-fit model for each dropout-diagnostic combination yielded similar results to our second confidence test which was 136 based on drawing random samples from the best-fit model and then re-computing the log likelihood value. In Table 7.2 we list all of the models that fall within the 68% and 99.9% confidence envelopes for the cumulative dropout-diagnostic results. The second test yielded broader confidence intervals, so we used the results of the second test for Table 7.2 in order to be conservative. Models outside of the 99.9% interval can be ruled out, while models within it cannot. Moreover, models within the 68% confidence interval cannot be distinguished amongst one another. With confidence intervals assigned to our best-fit models we can now discuss which of the semi-analytic models are favored given our data sets and our methodology. However, before proceeding to the discussion of the scientific implications of our results, we ran our third Monte-Carlo test to test for the stability of our results. Table 7.3 lists the best-fit models when we applied our second test, but to all models. That is for each model we re-computed – multiple times – the log likelihood values by drawing random samples from the smeared model density functions and then ranking the results. We can see that the order remains similar to that in Table 7.2, in that all of the re-fit models fall within the 68% confidence interval. We can therefore state that models 93, 75, 219, and 237 are our best-fit models using the diagnostic and dropout samples employed in this work. Again, this is without applying any a priori constraints. In Fig. 7.1 we show a mosaic of color-magnitude density functions for the overall best-fit model – model 93. In Fig. 7.2-7.5 we show plots of data points that were randomly drawn from the scattered model density functions of our best-fit model – model 93. We can compare these figures to the real data figures in §3.7 to see the relative agreement between the model and the data photometric colors. We also show sample Balmer-break colors for the B-dropouts of one of the poor-fit models (see Fig. 7.6). Furthermore, the top four models and models 147, 165, 21, and 3 are the only models that are not ruled out by our analysis. A quick glance at Table 7.2 reveals that the models residing in the 68% confidence interval possess the same values for the parameters that control the quiescent star formation and the relative dustiness. In contrast, there is a high-degree of variability in the parameters controlling the relative burstiness of the models. Taking account of all the models down to the 99.9% confidence interval shows the same behavior, except that the α∗ 137 parameter takes on a different value. We discuss the implications of these results below. 7.2 7.2.1 Parameter Fits – Implications Burst-driven Star Formation Parameters It is quite clear from Table 7.2 that our methodology and the available data have failed to narrow down the αburst and αburst bulge parameters. In the 99.9% confidence interval, nearly all permutations are possible. Recall from §2.2.5 that the two burst parameters used for the fitting control the degree of dependence of burst efficiency on the relative mass ratios of the merging galaxies. Higher αburst and αburst bulge parameter values indicate a strong dependence on the relative mass ratio, smaller values indicate the opposite. Stronger dependence leads to more efficient bursts, that is more available cold gas is turned into stars. However, as stated, it is hard to tell whether stronger or weaker dependence is preferred, nor can we rule anything out. Looking back at our exploratory work in §4 this apparent lack of definitive results is most likely a sign that our tests are not sensitive enough to distinguish between the various αburst and αburst bulge values. Most likely this is due to the relatively large scatter in the data. From §4 we know that the burst parameters affect the width of scatter in our color-magnitude diagnostics, however, the relative difference in scatter is quite subtle. The data sets used in our likelihood analysis simply cannot discern between the low and high αburst values. In addition, as was shown in §4, the remaining burst parameters that control burst efficiencies exhibit even subtler effects in our color-magnitude diagrams down to our magnitude limit of z850 < 27. Indeed we require to go much fainter in z850 to observe significant differences in the relative effects of burstiness in our models. As was stated in §4 the color differences between models with high degree of burstiness and those that have low burstiness, are only apparent at the faint end, fainter than z850 ∼ 27. If we probe to z850 ∼ 30 we notice that models with high degree of burstiness exhibit roughly the same Balmer-break color mean as model with low degree of burstiness, but the former exhibit many more blue objects. That is we observe a tail of faint and blue objects in very 138 bursty models. Looking at the distribution of stellar masses and star formation histories for these objects reveals that these are largely moderately massive objects that have recently undergone a merger-induced star formation burst. The magnitude cutoff imposed by our current data results in us missing many of these faint and blue galaxies. The current implementation of burst-driven star formation recipe results in only subtle observational effects down to our current photometric limits. With our current data set, our likelihood analysis fails to discern the relative importance of burstiness. Substantially deeper data is required to observe the fainter end and perhaps help discern among the different burst modes. 7.2.2 Quiescent Star Formation Parameters In the case of parameters controlling quiescent star formation, namely τ∗0 and α∗ , our models favor a τ∗0 = 12 and an α∗ = 0. The high τ∗0 value corresponds to longer time-scales. From our exploratory tests in §4, a high τ∗0 value has a much narrower Balmer-break color distribution, especially at the red end, where a low τ∗0 value has a long red tail. In addition, the mean of the distribution is significantly bluer in the case of the high τ∗0 value. Our likelihood analysis excludes models with low τ∗0 . Therefore our likelihood analysis favors models that exhibit accelerated quiescent star formation; models with enhanced stellar mass production (see §2). These models produce distribution of galaxies with much narrower Balmer-break color distributions, along with bluer mean color. The models that fail, or are excluded by our fits, exhibit color distributions that are much too broad and much too red, on the order of 0.5 mag to red. The α∗ corresponds to the power index on the circular velocity dependence with respect to the star formation rate (see §2.2.6). In our work in Idzi et al. (2004) (and the work done by Somerville, Primack, & Faber (2001)) we used high α∗ values to construct our models. This was in large part due to historical reasons, since models with high α∗ values matched high-redshift observations quite well, qualitatively speaking. However, low α∗ could not be ruled out from our earlier work. Through this analysis though we see that low α∗ values are preferred, and that the high and even moderate values are excluded. 139 Indeed, models within the 68% confidence interval all favor α∗ = 0, indicating no direct dependence on circular velocity. If we include models out to the 99.9% limit, we see models with α∗ = 0.5, indicating a weak explicit dependence on circular velocity. In §4 we saw how varying α∗ affected the UV and Balmer-break color distributions (see Fig. 4.16 and Fig. 4.17). The favored models exhibit Balmer-break color distributions that are relatively broad with a long tail on the blue end. The mean of the color distribution is also bluer relative to the cases with high α∗ . Even though the UV-color distribution does not exhibit a strong difference, we still see a bluer color distribution for our best-fit models. The favored quiescent star formation recipe seems to indicate that the star formation rate depends exclusively on the product of the time-scale τ∗0 parameter and the dynamical time (see §2.2.6). The quiescent star formation rate seems to be independent or very weakly dependent on the circular velocity. The α∗ in our recipe creates a relation between color and luminosity that may or may not exist in the data, so it seems that the data favors models that do not, or very weakly, scale the star formation rate with galaxy’s circular velocity. 7.2.3 Dust Parameter The optical depth parameter, τdust, 0 , is favored to be high. Indeed, back in §4 we extensively tested the parameters controlling dust and we saw how our preliminary analysis favored more dusty models. This only re-affirms that high optical-depth models are favored over those with moderate and low dust. Moreover, the best-fit values of the dust parameter corresponds to the empiricallyderived values found by previous research for the high redshift galaxy population. We now present the various properties of the best-fit model – Model 93 – galaxies, specifically those pertaining to the stellar-mass assembly. We include results of V-dropout galaxies, even though we did not explicitly fit the V-dropout sample. 140 7.3 Properties of High-Redshift Galaxies In Fig. 7.7-7.9 we show the stellar masses of our color-selected model galaxies. The stellar masses range from 108 to 1010 M# , which is roughly 1.5 orders of magnitude less than the stellar masses of the present day L∗ spirals and ellipticals – this indicates that the Lyman-break galaxies are not the fully assembled progenitors of the present-day L > L∗ galaxies (Giavalisco, Steidel, & Macchetto 1996; Steidel et al. 1996a), and that several generations of merging events, or higher star generation per event, must take place between V-dropouts and the present epoch. The median masses of the U-, B-, and V-dropout samples are Log[Mstar ] ∼ 9.75, 9.65, and 9.62, respectively. The median masses were computed for galaxies brighter than V606 < 27, i775 < 27, and z850 < 27 (∼ 1500 Å), respectively. The median mass for the B-dropouts is about 0.5 dex higher than that seen in Idzi et al. (2004). The progressive increase in the median stellar mass indicates growth in stellar content. We also note that even though it is not till the U-dropout population that we observe galaxies with Log[Mstar ] ∼ 11, the V-dropout population exhibits galaxies on the order of Log[Mstar ] ∼ 10.5, implying significant stellar populations already present by z ∼ 5 epoch. To further explore the last point we have looked at the mean stellar masses of all L∗ galaxies measured in rest-frame UV and predicted by our model at z ∼ 3 and z ∼ 4. We find that at z ∼ 3, with m∗ = 24.358 (UV rest- frame), we get a mean value of Log[Mstar ] = 10.65 (M# ) in a m∗ ± 0.5 magnitude interval, and at z ∼ 4, with m∗ = 24.998 (UV rest-frame), we get a mean value of Log[Mstar ] = 10.40 (M# ), again in a m∗ ± 0.5 magnitude interval. This corresponds to a mass build-up of approximately ∼ 77%. This type of mass build-up between z ∼ 4 and z ∼ 3 is larger than what was seen by Idzi et al. (2004), where a 40% build-up was seen. However, we note that our best-fit model predicts much more massive galaxies in those epochs than the results predicted in Idzi et al. (2004). The mean stellar masses of L∗ galaxies are about a factor of 10 bigger in this case. We also see a similar stellar mass build up between the z ∼ 4 and z ∼ 3 epochs, albeit somewhat smaller in scale (∼ 50%). The results remain nearly the same for all of the other models within the 68% 141 confidence interval. In fact, all of the models down to the 99.9% confidence interval exhibit similar results. It is only when we consider models outside of this statistical envelope where we begin to see significant differences, however, those models are ruled-out by our analysis. This behavior holds true for the rest of the properties described here. Drawing on the stellar mass distribution results we plot in Fig. 7.10-7.12 the mass distributions of all (i.e. not just color-selected) galaxies from our mock catalog, limited to galaxies with Log[Mstar ] greater than the median values found in Fig. 7.7-7.9 and spanning the corresponding dropout sample redshift range. We select roughly ∼ 80 − 90% of model galaxies with our color selection criteria, down to the limiting magnitudes. In terms of stellar mass, we select 91, 87, and 77% of the stellar mass for the U-, B-, and V-dropout samples. Hence, with our color criteria, we ’observe’ the vast majority of the stellar mass that resides in galaxies more massive than the respective median Log[Mstar ] values quoted earlier. However, if we include all galaxies down to our model run stellar mass cut, not just the ones more massive than the median Log[Mstar ], we recover only 69, 56, and 36% of the stellar mass for the U-, B-, and V-dropouts. Even though our stellar mass recovery rate is better than what we have seen in our preliminary studies (Idzi et al. 2004), the current optical survey still only recover the most-massive and most UV-bright galaxies. We miss large portions of stellar mass which resides in UV-faint galaxies. Moreover, we still miss nearly a quarter of the stellar mass from the relatively massive UV-faint V-dropout galaxies. In contrast though, the stellar mass recovery rates are quite high for the relatively massive and UV-bright Uand B-dropout galaxies. The best-fit model also provides us with the mean ages of our color-selected galaxies. In Fig. 7.13-7.15 we show the distribution of stellar-mass-weighted ages. The median ages of the U-, B-, and V-dropout samples are 550, 350, and 240 Myrs, respectively. Again, as with the median stellar masses, these values were computed for galaxies brighter than V606 < 27, i775 < 27, and z850 < 27, for the U-, B-, and V-dropout samples. As expected, the median stellar age becomes progressively older from epoch to epoch. The spread in ages also gets broader. The oldest galaxies in the U-, B-, 142 and V-dropout samples are 1.2 Gyr, 730, and 500 Myrs old, respectively. In each sample though, there is a broad range of both young and old galaxies indicating active star formation. In addition, the median age of 240 Myrs for the V-droputs indicates that even by the z ∼ 5 epoch substantial star formation events were taking place. This is further supported by a tail of Log[Mstar ] > 10.0 galaxies seen in the V-dropout distribution. The maximum ages fit within the ages permitted by our adopted cosmology. The oldest V-dropout galaxies (at ∼ 500 Myrs) are about half the age of the universe at that epoch. In addition to stellar masses and mean ages of our color-selected galaxies, we can also look at the smoothed SFRs of the sample galaxies. In Fig. 7.16-7.18 we show the distribution of star formation rates. The median SFRs of the U-, B-, and V-dropout samples are 5.62, 7.76, and 10.72 M# per year, respectively. Once again, as with the median stellar masses and the mean ages, these values were computed for galaxies brighter than V606 < 27, i775 < 27, and z850 < 27, for the U-, B-, and V-dropout samples. The maximum SFRs for each sample are 120.0, 75.8, and 65.5 M# per year. We can see that in our best-fit model, the star formation rates are fairly steady across the various epochs, rising steadily when we move towards the z ∼ 3 epoch. The raw numbers are similar to those found in previous works (Idzi et al. 2004; Somerville, Primack, & Faber 2001). With regards to star formation, a useful diagnostic to look at is the mean time since last merger. We find that the values of the median time since last merger event are 900, 600, and 450 Myrs, for the U-, B-, and V-dropout samples down to the V606 < 27, i775 < 27, and z850 < 27 limits. We see the trend of merging events becoming less common, in an average sense, as we go from z ∼ 5 to z ∼ 3. However, the distributions for time since last merger events are very broad, spanning instances where galaxies just underwent a merger to instances where the time since last merger is comparable to the age of the universe at the given epoch. For example, the distribution for U-dropouts goes from 0.0002 to 2.5 Gyrs, with a mean of 0.9 Gyr and standard deviation of 0.5 Gyr. This indicates that mergers are quite active throughout all of the redshift slices studied here. We also find that about 10% of U-dropout galaxies have undergone a major merger within 143 the past 500 Myrs, where a major merger occurs when the ratio of the masses of the two merging galaxies is at least 30%. For B-, and V-dropouts this ratio goes up, as expected, to 20% and 36%, respectively. Looking at all mergers, the ratios for the U-, B-, and V-dropouts are 18%, 30%, and 54%, respectively. Finally, we can contrast our results to ISAAC-selected galaxies that had SEDs fitted to them by Wiklind et al. We can compare the derived ensemble parameters to the results from our best-fit model – model 93. As a first step we position match the ISAAC-selected galaxies to the U- and B-dropout samples to select matching sources. We then compute some simple statistics. We find that 319 sources out of 569 available U-dropouts are matched against the ISAAC-selected catalog. For B-dropouts we find 77 out of 275 sources. We find that the median log stellar mass is around 9.57 for the U-dropout matched sample, and around 10.5 for the B-dropout matched sample. These numbers compare favorably to the best-fit model (model 93) results, however the B-dropout matched sample’s log stellar mass is 0.4 mag higher than our best-fit model results. Indicating perhaps that the ISAAC-selected catalog has preferentially more massive Lyman-break dropouts. Looking at the mean ages we get 226 and 411 Myrs for the U- and B-dropout matched samples, respectively. Although the B-dropout matched sample’s age compares favorably to the median bestfit model (model 93) age of 350 Myrs, the U-dropout matched sample’s age is considerably lower than the median best-fit model (model 93) age of 550 Myrs. 7.4 Summary In this project we adopted a robust approach to investigate several fundamental properties of Lyman-break galaxies by statistically comparing photometric observations with the predictions of semi-analytic models based on the Cold Dark Matter theory of hierarchical structure formation. We used a sample of U and B435 -dropouts from the Great Observatories Origins Deep Survey, and complemented the ACS optical B435 , V606 , i775 , and z850 data with the VLT ISAAC J, H, and Ks 144 and IRAC 3.6, 4.5, 5.8, and 8.0 observations. We ran a set of 144 semi-analytic models, varying parameters that control the star formation rates and the relative dustiness of model galaxies. We then extracted U , B435 , and V606 -dropouts from our semi-analytic mock catalogs using the same color criteria and magnitude limits that were applied to the observed sample. Using the input model catalogs, we constructed density functions gridded in color-magnitude space and convolved those density functions with observational scatter templates derived from Monte-Carlo data simulations. We then computed likelihoods using the data and the scattered model density functions for UVcontinuum and Balmer-break color-magnitude diagnostics. Finally, we ran Monte-Carlo simulations to assign confidence intervals and to test the overall stability of our results. We adopt a forward treatment approach in our analysis. In the traditional approach individual galaxies are fit by spectral energy distribution functions in order to derive physical quantities such as stellar masses, ages, dust extinctions. There are a number of disadvantages to the traditional approach. The star formation histories are highly simplistic (i.e. they have singular metallicity, no bursts, no dependence of extinction on past history, etc.). There is no explicit requirement that there be any self-consistency in the results from galaxy to galaxy, or epoch to epoch. Moreover, it is very difficult to take into account systematic biases in the photometry and survey incompleteness. It is also difficult to draw conclusions of the parent populations of observed galaxies. The traditional approach speaks to the observed population only. In the forward treatment that we adopt here we construct noise-free models and subject them to all of the observational imperfections that we can account for prior to making our statistical comparisons to the data. Rather than attempting to derive physical quantities galaxy by galaxy, we look at the ensemble of quantities derived from the models that we find consistent with the data. We also enforce epoch-to-epoch self-consistency by summing derived likelihoods across redshift slices. Regardless of the merits of a particular star formation prescription invoked by our models, we at the very least produce a valuable cross-check on the simplistic models, with an accounting of merging, chemical evolution, and dust that vary in a sensible way with cold gas mass, metallicity and other variables. In the end, the comparison of our 145 model-derived quantities like mean extinction (and variance), mean age, stellar mass, etc. to the quantities assigned by simplistic models can give us a much better appreciation for whether these derived physical quantities are robust. We find that given our data, models, and our methodology we can rule out certain models and state which models are preferred. We find that our models favor high dust content and exclude low dust content models. Furthermore, the optical depth value that yielded the best fit corresponds to the relative dust abundances observed in the real, high-redshift galaxy populations. We are unable to discern among models with varying burst efficiencies. The effects of the burst parameters that we chose to vary, which mainly affect the scatter in the color distribution, are too subtle compared to the relatively large scatter in the data. The remaining burst parameters that we chose to hold fixed would not be easily discerned either. In the observational plane, the most significant differences between the less-bursty and the more-bursty models occur at magnitudes below our detection threshold. We would need to probe fainter magnitude limits in order to note significant differences among the various burst modes. The determinant factor, according to our models, lies in the faint, blue, moderately massive galaxies that have recently undergone an episode of star formation. The more bursty modes exhibit a larger proportion of these types of galaxies. In addition to varying the relative burstiness of our models, we explored the effects of quiescent star formation. We looked at both quiescent and enhanced quiescent models. Our analysis favors models with enhanced quiescent star formation. The low τ∗0 models are excluded by our fits as they yield Balmer-break and UV color distributions that do not match our dropout data. The Balmer-break colors of the excluded τ∗0 models are too red relative to the data, indicating that the data favors models with a higher ratio of young stellar populations to the old ones. In other words, the enhanced quiescent star formation mode is preferred. In addition, we find that our best-fit models rule out any strong explicit dependence of star formation on circular velocity in our quiescent star formation scaling law. The data shows no explicit correlation between the star formation rate and galaxy’s circular velocity. It is important to note though that this finding does not state that there is no dependance 146 on circular velocity. Our quiescent star formation recipe still depends on the dynamical time-scale, which indirectly has a correlation with circular velocity. The overall observational effect of the cumulative star formation rate is largely governed by the enhanced quiescent star formation mode. The parameters that control the relative burstiness have very subtle observational effects down to our magnitude limits. If our models are correct, we need to probe deeper magnitudes to discern the relative strengths of the various burst modes as they impact the observational plane. From the properties yielded by our best-fit models we find that we select majority of the stellar mass (80-90%, across samples) with our color-selection criteria that is contained in massive, UV-bright galaxies. In contrast, the fractions of seen stellar masses for each sample decline substantially (40-70%) when we consider all galaxies. This indicates that our current optical surveys are effective at selecting UV-bright, massive galaxies, but fail to select most of the stellar mass (especially at z ∼ 4, 5 redshifts), which remains hidden in UV-faint, moderately massive to dwarf galaxies. In addition, we find that our best-fit models predict a ∼ 77% mass build-up between the z ∼ 4 and z ∼ 3 epochs for the UV rest-frame L∗ galaxies, and a smaller ∼ 50% build-up between z ∼ 5 and z ∼ 4 epochs. This indicates an on-going process of stellar-mass assembly between the z ∼ 5 and the z ∼ 3 epochs. Furthermore, we find that for our z ∼ 3 sample, the stellar masses range from 108 to 1010 M# , which is roughly 1.5 orders of magnitude less than the stellar masses of the present day L∗ spirals and ellipticals – this indicates that the z ∼ 3 Lyman-break galaxies are not the fully assembled progenitors of the present-day L > L∗ galaxies. Finally, we find that quite a few of the z ∼ 5 galaxies have Log[Mstar ] > 10 (M# ), and that the median age of the z ∼ 5 galaxy population is about 240 Myrs, with quite a few older galaxies – reaching ages as high as 500 Myrs. This points to an already active star formation well before the z ∼ 5 epoch. 147 Figure 7.1 Best-fit model observationally scattered density functions. From top-left, clockwise, Udropout V606 - i775 vs i775 U-dropout V606 - IRAC 3.6 vs V606 B-dropout z850 - IRAC 4.5 vs z850 and B-dropout i775 - z850 vs z850 . The limits are the same as given in Table 6.1. 148 Figure 7.2 Random draws from the best-fit model observationally scattered density function. Udropouts with V606 - i775 vs i775 colors. 149 Figure 7.3 Random draws from the best-fit model observationally scattered density function. Udropouts with V606 - IRAC 3.6 vs V606 colors. 150 Figure 7.4 Random draws from the best-fit model observationally scattered density function. Bdropouts with i775 - z850 vs z850 colors. 151 Figure 7.5 Random draws from the best-fit model observationally scattered density function. Bdropouts with z850 - IRAC 4.5 vs z850 colors. 152 Figure 7.6 Random draws from a poor-fit model observationally scattered density function. Bdropouts with z850 - IRAC 4.5 vs z850 colors. Note the different character of the Balmer-break colors as compared to Fig. 7.5. 153 Figure 7.7 Stellar masses of the color-selected U-dropout model galaxies. The filled-diamond symbols show stellar masses of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. The histogram shows the projected distributions for the same color-selected model galaxies with an imposed z850 < 27 magnitude limit (shown as a red dash-line). The predicted masses are about 1.5 orders of magnitude lower than the stellar masses of the present day L∗ spirals and ellipticals. 154 Figure 7.8 Stellar masses of the color-selected B-dropout model galaxies. The filled-diamond symbols show stellar masses of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. The histogram shows the projected distributions for the same color-selected model galaxies with an imposed z850 < 27 magnitude limit (shown as a red line). 155 Figure 7.9 Stellar masses of the color-selected V-dropout model galaxies. The filled-diamond symbols show stellar masses of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. The histogram shows the projected distributions for the same color-selected model galaxies with an imposed z850 < 27 magnitude limit (shown as a red line). 156 Figure 7.10 This figure illustrates the stellar mass distribution of all model-derived galaxies spanning the color-selected redshift range and with Log[Mstar ] > 9.71 (M# ) (the median value from Fig. 7.7). Galaxies were binned into 0.25 magnitude intervals and weighted by their corresponding stellar mass. A red dash-line is included to delineate our observational magnitude limit. This figure shows the amount of model-predicted mass potentially missed by the current optical surveys down to our magnitude limit. 157 Figure 7.11 This figure illustrates the stellar mass distribution of all model-derived galaxies spanning the color-selected redshift range and with Log[Mstar ] > 9.65 (M# ) (the median value from Fig. 7.8). Galaxies were binned into 0.25 magnitude intervals and weighted by their corresponding stellar mass. A red dash-line is included to delineate our observational magnitude limit. 158 Figure 7.12 This figure illustrates the stellar mass distribution of all model-derived galaxies spanning the color-selected redshift range and with Log[Mstar ] > 9.62 (M# ) (the median value from Fig. 7.9). Galaxies were binned into 0.25 magnitude intervals and weighted by their corresponding stellar mass. A red dash-line is included to delineate our observational magnitude limit. 159 Figure 7.13 Stellar-mass weighted ages of the color-selected U-dropout model galaxies. The filleddiamond symbols show ages of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. The histogram shows the projected distributions for the same color-selected model galaxies with an imposed z850 < 27 magnitude limit (shown as a red line). 160 Figure 7.14 Stellar-mass weighted ages of the color-selected B-dropout model galaxies. The filleddiamond symbols show ages of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. The histogram shows the projected distributions for the same color-selected model galaxies with an imposed z850 < 27 magnitude limit (shown as a red line). 161 Figure 7.15 Stellar-mass weighted ages of the color-selected V-dropout model galaxies. The filleddiamond symbols show ages of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. The histogram shows the projected distributions for the same color-selected model galaxies with an imposed z850 < 27 magnitude limit (shown as a red line). 162 Figure 7.16 Smoothed (over 10 Myr bins) star formation rates of the color-selected U-dropout model galaxies. The filled-diamond symbols show SFRs of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. The histogram shows the projected distributions for the same color-selected model galaxies with an imposed z850 < 27 magnitude limit (shown as a red line). 163 Figure 7.17 Smoothed (over 10 Myr bins) star formation rates of the color-selected B-dropout model galaxies. The filled-diamond symbols show SFRs of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. The histogram shows the projected distributions for the same color-selected model galaxies with an imposed z850 < 27 magnitude limit (shown as a red line). 164 Figure 7.18 Smoothed (over 10 Myr bins) star formation rates of the color-selected V-dropout model galaxies. The filled-diamond symbols show SFRs of the individual color-selected model galaxies vs. their corresponding z850 magnitudes. 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This is made possible using the spherical collapse model, one of the apparently gross oversimplifications that seems to work surprisingly well. We imagine a spherical patch of the universe with a uniform overdensity δi within a radius ri at a very early time ti (often called a ”top-hat” perturbation). We assume that the collapsing shells of matter do not cross. If we consider a particle at radius r, Birkhoff’s theorem Birkhoff (1923) tells us that we can ignore the mass outside this radius in computing the motion of the particle. The equation of motion for our particle (in physical, rather than comoving, coordinates) is then, GM Λ d2 r =− 2 + r dt2 r 3 (A.1) where M = (4π/3)ri3 ρb (ti )(1 + δi ) and ρb (ti ) is the background density of the universe at ti . Integrating this equation gives, 183 ṙ = H0 3 Ω0 r3 (1 + δi ) i3 + ΩΛ r2 − K r ai 4 (A.2) where K is a constant of integration. We may fix this by noting that if we have picked ti early enough that Ω ∼ 1 at that time, linear theory tells us that the initial velocity is, "5 ! ΩR Ω0 δi + 2 + ΩΛ . ṙ(ti ) = H0 ri 1 − 3 a3i ai (A.3) Peebles (1984). At the point of maximum expansion, or “turnaround”, ṙ = 0. If we set equation (A.3) to zero, we obtain a cubic equation for rta , the radius of the perturbation at turnaround, which must be solved numerically for the general cosmology given here, but for special cases it can be solved analytically (cf. Padmanabhan (1993)). From a symmetry argument, we note that the time when the perturbation collapses to a point, tcoll , is always twice tta (the time at maximum expansion). We can now write an implicit equation for the mass of a perturbation that is collapsing at tcoll , tcoll = 2 rta 2 0 dr . ṙ (A.4) We know the mass and the radius at turnaround, so we can calculate the density of the perturbation at turnaround, ρta . Of course the perturbation will not really collapse to a point. Before that happens, shell crossing will occur, and it will virialize. We can find the radius after virialization in terms of the turnaround radius using the virial theorem. The total energy at turnaround is Lahav et al. (1991), E = UG,ta + UΛ,ta = − 1 3 GM 2 2 − ΛM rta 5 rta 10 (A.5) where the second term is due to the cosmological constant. Now using the virial theorem for the final state, 184 1 Tf = − UG,f + UΛ,f . 2 From conservation of energy we then have 1 2 UG,f (A.6) + 2UΛ,f = UG,ta + UΛ,ta . This leads to a cubic equation for the ratio of the virial radius rvir to the turnaround radius rta . We now know rvir and can write down the virial density, ∆c (z) ≡ ρvir Ω(z) . Ω0 ρ0c (1 + z)3 (A.7) We now have a relationship between the mass, virial radius, and collapse redshift z. If we assume a radial profile for the virialized halo, we can use the virial theorem again to relate these quantities to the velocity dispersion. If we assume that the halo is a singular isothermal sphere, ρ ∝ r−2 , truncated at the virial radius, then we have, GM Λr2 3 2 σ = − vir 2 2rvir 18 (A.8) or, in terms of the circular velocity Vc , assuming Vc2 = 2σ 2 , Vc2 = GM ΩΛ 2 2 − H r rvir 3 0 vir (A.9) We can now translate between mass and velocity dispersion at any given redshift. Note that in universes with a non-zero cosmological constant, halos of a given circular velocity are less massive because of the Λ contribution to the energy. In practice, we use the fitting formula of Bryan & Norman (1997) for the virial density, ∆c = 18π 2 + 82x − 39x2 (A.10) ∆c = 18π 2 + 60x − 32x2 (A.11) for a flat universe and, 185 for an open universe, where x ≡ Ω(z) − 1. This formula is accurate to1 % in the range 0.1 ≤ Ω ≤ 1, which is more than adequate for our purposes. We now can write down the general expression for rvir in closed form, rvir = 3 Ω(z) M 4π ∆c (z)Ω0 ρc,0 41/3 1 . 1+z (A.12) In conjunction with equation A.9, this allows us to calculate the circular velocity and viral radius for a halo with a given mass at any redshift z. These expressions are valid for open cosmologies with Λ = 0 and flat cosmologies with non-zero Λ. 186 Figure A.1 The relationship between halo mass and virial velocity from the spherical tophat model, at z = 0 (bottom set of lines), z = 1, and z = 3 (top), for the cosmologies discussed in the text. The relation depends (weakly) on cosmology and (strongly) on redshift (This figure was reproduced, with permission, from Somerville & Primack (1999)). 187 Appendix B Table of Model Runs 188 Table B.1. List of All Models Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 1 12.0 0.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 2 12.0 0.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 3 12.0 0.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 4 12.0 1.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 5 12.0 1.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 6 12.0 1.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 7 12.0 2.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 8 12.0 2.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 9 12.0 2.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 10 1.5 0.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 11 1.5 0.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 12 1.5 0.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 13 1.5 1.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 14 1.5 1.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 15 1.5 1.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 16 1.5 2.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 17 1.5 2.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 18 1.5 2.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 19 12.0 0.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 20 12.0 0.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 21 12.0 0.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 22 12.0 1.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 23 12.0 1.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 24 12.0 1.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 25 12.0 2.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 26 12.0 2.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 27 12.0 2.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 28 1.5 0.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 29 1.5 0.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 30 1.5 0.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 31 1.5 1.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 189 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 32 1.5 1.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 33 1.5 1.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 34 1.5 2.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 35 1.5 2.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 36 1.5 2.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 37 12.0 0.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 38 12.0 0.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 39 12.0 0.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 40 12.0 1.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 41 12.0 1.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 42 12.0 1.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 43 12.0 2.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 44 12.0 2.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 45 12.0 2.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 46 1.5 0.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 47 1.5 0.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 48 1.5 0.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 49 1.5 1.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 50 1.5 1.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 51 1.5 1.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 52 1.5 2.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 53 1.5 2.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 54 1.5 2.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 55 12.0 0.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 56 12.0 0.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 57 12.0 0.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 58 12.0 1.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 59 12.0 1.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 60 12.0 1.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 61 12.0 2.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 62 12.0 2.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 190 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 63 12.0 2.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 64 1.5 0.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 65 1.5 0.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 66 1.5 0.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 67 1.5 1.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 68 1.5 1.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 69 1.5 1.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 70 1.5 2.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 71 1.5 2.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 72 1.5 2.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 73 12.0 0.0 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 74 12.0 0.0 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 75 12.0 0.0 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 76 12.0 3.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 77 12.0 3.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 78 12.0 3.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 79 12.0 4.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 80 12.0 4.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 81 12.0 4.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 82 1.5 0.0 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 83 1.5 0.0 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 84 1.5 0.0 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 85 1.5 3.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 86 1.5 3.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 87 1.5 3.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 88 1.5 4.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 89 1.5 4.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 90 1.5 4.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 91 12.0 0.0 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 92 12.0 0.0 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 93 12.0 0.0 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 191 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 94 12.0 3.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 95 12.0 3.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 96 12.0 3.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 97 12.0 4.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 98 12.0 4.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 99 12.0 4.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 100 1.5 0.0 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 101 1.5 0.0 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 102 1.5 0.0 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 103 1.5 3.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 104 1.5 3.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 105 1.5 3.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 106 1.5 4.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 107 1.5 4.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 108 1.5 4.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 109 12.0 0.0 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 110 12.0 0.0 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 111 12.0 0.0 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 112 12.0 3.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 113 12.0 3.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 114 12.0 3.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 115 12.0 4.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 116 12.0 4.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 117 12.0 4.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 118 1.5 0.0 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 119 1.5 0.0 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 120 1.5 0.0 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 121 1.5 3.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 122 1.5 3.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 123 1.5 3.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 124 1.5 4.5 1.0 2.0 0.5 0.5 0.5 1.5 0.5 0.3 192 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 125 1.5 4.5 1.0 2.0 0.5 0.5 0.5 1.5 1.0 0.3 126 1.5 4.5 1.0 2.0 0.5 0.5 0.5 1.5 1.5 0.3 127 12.0 0.0 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 128 12.0 0.0 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 129 12.0 0.0 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 130 12.0 3.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 131 12.0 3.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 132 12.0 3.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 133 12.0 4.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 134 12.0 4.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 135 12.0 4.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 136 1.5 0.0 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 137 1.5 0.0 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 138 1.5 0.0 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 139 1.5 3.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 140 1.5 3.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 141 1.5 3.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 142 1.5 4.5 1.0 2.0 0.5 1.5 0.5 1.5 0.5 0.3 143 1.5 4.5 1.0 2.0 0.5 1.5 0.5 1.5 1.0 0.3 144 1.5 4.5 1.0 2.0 0.5 1.5 0.5 1.5 1.5 0.3 145 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 146 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 147 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 148 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 149 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 150 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 151 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 152 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 153 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 154 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 155 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 193 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 156 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 157 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 158 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 159 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 160 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 161 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 162 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 163 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 164 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 165 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 166 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 167 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 168 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 169 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 170 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 171 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 172 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 173 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 174 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 175 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 176 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 177 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 178 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 179 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 180 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 181 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 182 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 183 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 184 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 185 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 186 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 194 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 187 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 188 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 189 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 190 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 191 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 192 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 193 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 194 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 195 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 196 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 197 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 198 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 199 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 200 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 201 12.0 0.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 202 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 203 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 204 12.0 1.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 205 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 206 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 207 12.0 2.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 208 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 209 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 210 1.5 0.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 211 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 212 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 213 1.5 1.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 214 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 215 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 216 1.5 2.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 217 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 195 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 218 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 219 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 220 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 221 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 222 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 223 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 224 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 225 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 226 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 227 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 228 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 229 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 230 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 231 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 232 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 233 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 234 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 235 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 236 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 237 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 238 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 239 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 240 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 241 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 242 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 243 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 244 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 245 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 246 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 247 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 248 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 196 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 249 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 250 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 251 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 252 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 253 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 254 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 255 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 256 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 257 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 258 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 259 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 260 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 261 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 262 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 263 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 264 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 265 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 266 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 267 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 268 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.5 0.5 0.3 269 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.5 1.0 0.3 270 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.5 1.5 0.3 271 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 272 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 273 12.0 0.0 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 274 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 275 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 276 12.0 3.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 277 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 278 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 279 12.0 4.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 197 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 280 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 281 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 282 1.5 0.0 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 283 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 284 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 285 1.5 3.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 286 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.0 0.5 0.3 287 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.0 1.0 0.3 288 1.5 4.5 1.0 2.0 0.5 1.0 0.5 1.0 1.5 0.3 289 12.0 0.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 290 12.0 0.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 291 12.0 0.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 292 12.0 1.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 293 12.0 1.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 294 12.0 1.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 295 12.0 2.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 296 12.0 2.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 297 12.0 2.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 298 1.5 0.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 299 1.5 0.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 300 1.5 0.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 301 1.5 1.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 302 1.5 1.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 303 1.5 1.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 304 1.5 2.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 305 1.5 2.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 306 1.5 2.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 307 12.0 0.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 308 12.0 0.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 309 12.0 0.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 310 12.0 1.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 198 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 311 12.0 1.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 312 12.0 1.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 313 12.0 2.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 314 12.0 2.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 315 12.0 2.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 316 1.5 0.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 317 1.5 0.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 318 1.5 0.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 319 1.5 1.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 320 1.5 1.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 321 1.5 1.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 322 1.5 2.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 323 1.5 2.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 324 1.5 2.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 325 12.0 0.0 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 326 12.0 0.0 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 327 12.0 0.0 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 328 12.0 3.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 329 12.0 3.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 330 12.0 3.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 331 12.0 4.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 332 12.0 4.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 333 12.0 4.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 334 1.5 0.0 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 335 1.5 0.0 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 336 1.5 0.0 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 337 1.5 3.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 338 1.5 3.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 339 1.5 3.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 340 1.5 4.5 1.0 1.0 0.5 0.5 0.5 1.5 0.5 0.3 341 1.5 4.5 1.0 1.0 0.5 0.5 0.5 1.5 1.0 0.3 199 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 342 1.5 4.5 1.0 1.0 0.5 0.5 0.5 1.5 1.5 0.3 343 12.0 0.0 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 344 12.0 0.0 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 345 12.0 0.0 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 346 12.0 3.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 347 12.0 3.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 348 12.0 3.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 349 12.0 4.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 350 12.0 4.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 351 12.0 4.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 352 1.5 0.0 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 353 1.5 0.0 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 354 1.5 0.0 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 355 1.5 3.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 356 1.5 3.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 357 1.5 3.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 358 1.5 4.5 1.0 1.0 0.5 1.5 0.5 1.5 0.5 0.3 359 1.5 4.5 1.0 1.0 0.5 1.5 0.5 1.5 1.0 0.3 360 1.5 4.5 1.0 1.0 0.5 1.5 0.5 1.5 1.5 0.3 361 12.0 0.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 362 12.0 0.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 363 12.0 0.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 364 12.0 1.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 365 12.0 1.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 366 12.0 1.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 367 12.0 2.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 368 12.0 2.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 369 12.0 2.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 370 1.5 0.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 371 1.5 0.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 372 1.5 0.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 200 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 373 1.5 1.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 374 1.5 1.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 375 1.5 1.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 376 1.5 2.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 377 1.5 2.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 378 1.5 2.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 379 12.0 0.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 380 12.0 0.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 381 12.0 0.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 382 12.0 1.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 383 12.0 1.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 384 12.0 1.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 385 12.0 2.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 386 12.0 2.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 387 12.0 2.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 388 1.5 0.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 389 1.5 0.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 390 1.5 0.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 391 1.5 1.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 392 1.5 1.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 393 1.5 1.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 394 1.5 2.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 395 1.5 2.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 396 1.5 2.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 397 12.0 0.0 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 398 12.0 0.0 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 399 12.0 0.0 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 400 12.0 3.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 401 12.0 3.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 402 12.0 3.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 403 12.0 4.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 201 Table B.1 (cont’d) Model τ∗0 α∗ '0SN αrh '0burst αburst '0burst bulge αburst bulge τdust, 0 βdust 404 12.0 4.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 405 12.0 4.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 406 1.5 0.0 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 407 1.5 0.0 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 408 1.5 0.0 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 409 1.5 3.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 410 1.5 3.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 411 1.5 3.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 412 1.5 4.5 1.0 1.0 0.5 1.0 0.5 1.5 0.5 0.3 413 1.5 4.5 1.0 1.0 0.5 1.0 0.5 1.5 1.0 0.3 414 1.5 4.5 1.0 1.0 0.5 1.0 0.5 1.5 1.5 0.3 415 12.0 0.0 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 416 12.0 0.0 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 417 12.0 0.0 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 418 12.0 3.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 419 12.0 3.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 420 12.0 3.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 421 12.0 4.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 422 12.0 4.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 423 12.0 4.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 424 1.5 0.0 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 425 1.5 0.0 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 426 1.5 0.0 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 427 1.5 3.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 428 1.5 3.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 429 1.5 3.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 430 1.5 4.5 1.0 1.0 0.5 1.0 0.5 1.0 0.5 0.3 431 1.5 4.5 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.3 432 1.5 4.5 1.0 1.0 0.5 1.0 0.5 1.0 1.5 0.3 202 Appendix C Tables of Lyman-Break Galaxies 203 Table C.1. U-dropout Lyman-break Sample ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 512 53.0014805 -27.7221255 22.6961 22.3532 22.2688 22.0879 20.2659 20.1823 968 53.0108820 -27.7260919 26.0686 25.5896 25.4363 25.3528 23.2376 23.1146 989 53.0112295 -27.7226726 27.3386 26.7572 26.5359 26.4851 23.7462 23.7243 1007 53.0114940 -27.7243115 26.1487 25.9077 25.7627 25.4897 23.6484 23.6455 1033 53.0119182 -27.7473601 26.9931 27.2173 26.3126 26.1417 25.2342 25.0088 1110 53.0130779 -27.7027692 26.4559 25.7761 25.7833 25.9796 25.0899 25.125 1125 53.0132503 -27.6985973 24.9727 24.8786 24.763 24.7586 23.7021 23.6022 1134 53.0133877 -27.7580074 22.5622 21.616 20.9484 20.6799 19.8234 20.0532 1141 53.0134939 -27.7489608 26.2201 25.283 24.9295 24.85 24.6904 24.782 1150 53.0136625 -27.7037702 24.9867 24.7324 24.5873 24.6105 23.1734 23.1212 1152 53.0137107 -27.7531745 25.2907 24.5246 23.8663 23.6935 23.0862 23.4603 1186 53.0143668 -27.7507923 24.7705 24.1117 23.6917 23.5998 23.5752 23.815 1198 53.0145505 -27.7279131 25.8641 24.9176 24.601 24.5974 23.2546 23.1888 1260 53.0154203 -27.7128851 23.2904 23.0465 22.9907 22.9891 23.844 24.6256 1273 53.0155577 -27.7230478 26.8191 26.2634 26.0296 25.6444 22.9319 22.828 1281 53.0156774 -27.7017035 23.6913 23.0352 22.4697 22.3809 21.9722 22.3712 1300 53.0158761 -27.7666035 26.037 25.7639 25.6764 25.5817 24.6471 24.7092 1332 53.0164951 -27.7336790 24.833 24.2967 23.3707 22.9043 21.1606 21.5253 1578 53.0201112 -27.7815540 24.9692 24.2422 23.577 23.4422 22.8132 23.2719 1617 53.0204803 -27.7117484 23.727 22.6853 21.6957 21.3518 19.8086 20.2616 1783 53.0223738 -27.7500135 26.4214 25.8267 25.641 25.5774 24.3902 24.1376 1851 53.0230720 -27.7525947 25.9217 24.7976 24.1948 23.967 24.2038 24.1266 1864 53.0231916 -27.7634793 26.5259 26.2127 25.8252 25.2922 23.79 23.9365 1907 53.0236441 -27.7088287 24.7481 24.0079 23.1888 22.9489 21.9779 22.4571 1957 53.0242668 -27.7787794 26.7609 26.8602 26.8505 26.5771 23.8988 23.59 2057 53.0257818 -27.7937485 26.1164 25.077 24.7562 24.7085 23.1466 23.5018 2073 53.0259711 -27.7289309 25.6218 25.0794 24.4146 24.2883 23.6286 23.9135 2349 53.0287764 -27.7758726 26.6573 26.4989 26.1108 25.739 22.8093 22.5888 2372 53.0290108 -27.7345758 26.8832 26.4826 25.7205 25.5016 24.5878 24.0665 2537 53.0306642 -27.7325175 24.8172 24.7506 24.5103 24.2537 22.8413 23.1836 2606 53.0312597 -27.7838600 26.1489 25.9777 25.9368 25.4698 24.4043 24.2671 204 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 2661 53.0316537 -27.7710869 25.9513 25.7667 25.4572 25.3568 23.7279 23.526 2670 53.0317854 -27.7053077 26.4644 26.1805 25.9063 25.1607 23.4456 23.6406 2707 53.0321459 -27.7850872 23.0744 22.2065 21.9301 21.705 21.9235 22.14 2721 53.0322830 -27.7722304 26.1307 25.3152 25.201 25.3055 24.4686 24.4961 2792 53.0329282 -27.7667834 22.4367 21.6568 21.4955 21.2655 21.5714 21.7497 2862 53.0335379 -27.7402519 23.7298 21.6288 20.548 20.1588 20.589 21.0245 2879 53.0336810 -27.7050657 24.2847 23.9261 23.7995 23.6996 22.1362 22.0768 3023 53.0349839 -27.7656582 27.0842 26.8014 26.3188 25.9425 23.6813 23.5971 3098 53.0356972 -27.7306395 25.6041 25.306 25.2032 25.2316 23.8268 23.9397 3292 53.0374862 -27.7181720 27.2368 26.3323 26.3217 26.3809 24.5982 25.0932 3297 53.0375433 -27.7824529 24.3758 23.7451 22.9954 22.7158 21.122 21.4354 3363 53.0380892 -27.7658309 25.2525 24.7908 24.5952 24.499 22.6272 22.4807 3414 53.0385707 -27.7132748 26.0732 25.4227 25.4105 25.5957 23.7128 24.1119 3495 53.0394109 -27.7992079 26.0247 25.7077 25.2386 25.5704 23.0307 22.8909 3562 53.0399970 -27.8055615 26.5126 26.4508 26.3003 26.3544 24.8007 24.999 3593 53.0401630 -27.6929450 25.8544 25.1224 24.739 24.6009 22.7802 22.8341 3639 53.0405270 -27.7744656 25.9268 25.8361 25.6276 25.604 23.9129 23.9295 3674 53.0407819 -27.7160198 25.9559 25.166 25.058 24.9936 24.0565 24.5866 3714 53.0411479 -27.8123606 24.9123 24.2925 24.1455 24.1153 24.1569 24.3985 3816 53.0419576 -27.8187116 19.7331 19.204 18.9155 18.9017 20.3017 20.8003 3870 53.0425891 -27.7961663 25.6218 24.9181 24.409 24.314 24.1716 24.709 3908 53.0428591 -27.7436186 24.5697 24.2362 23.6333 23.492 23.2912 23.7247 4068 53.0442326 -27.7742530 26.2413 25.804 25.2282 24.7436 21.2812 21.0845 4110 53.0444750 -27.8138092 24.2519 24.0717 23.5702 23.1576 21.9159 21.9632 4124 53.0445716 -27.7297080 23.8018 23.6765 23.5029 23.0366 22.0718 22.182 4217 53.0453707 -27.7593481 25.0903 24.935 24.8606 24.6653 23.3399 23.3981 4253 53.0456097 -27.7623826 23.1176 23.0316 22.6061 22.3951 21.6965 22.0098 4300 53.0459437 -27.7489047 22.5521 22.128 21.4078 21.1653 20.2831 20.7087 4476 53.0473129 -27.7255895 25.8852 24.907 24.6153 24.4241 24.6807 25.2036 4479 53.0473308 -27.7024629 24.9617 24.2525 23.8558 23.7814 23.7747 24.15 4481 53.0473362 -27.7401594 25.8502 25.5957 25.4336 25.3092 23.5586 23.5779 205 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 4568 53.0479303 -27.8175728 26.4142 26.0525 25.6362 25.1056 22.9692 23.0452 4654 53.0485435 -27.7218622 25.5896 25.4231 25.269 25.0657 23.9129 23.9987 4747 53.0492513 -27.7320127 24.4259 24.3914 24.1367 23.75 22.9208 23.2698 4846 53.0499257 -27.8052925 26.4539 25.6086 25.3449 25.2649 24.4249 25.0281 4901 53.0503405 -27.7034096 24.031 23.2009 22.9026 22.8137 23.0836 23.5632 4911 53.0504296 -27.8210608 25.6507 25.0003 24.8496 24.7506 24.7409 25.5874 4925 53.0505252 -27.8014364 27.004 26.8177 26.8736 26.8472 25.2589 25.4021 4982 53.0509170 -27.7724075 24.7037 23.6879 22.6214 21.9073 19.5814 19.7878 5100 53.0517474 -27.7391040 27.1357 27.0079 26.8763 26.839 25.4228 25.221 5237 53.0526160 -27.7022353 25.7755 24.6801 24.2736 24.1618 23.6644 24.5876 5239 53.0526678 -27.7250285 21.4401 20.1631 19.7069 19.576 20.4513 20.968 5263 53.0528265 -27.8419832 25.2821 25.2452 25.0448 24.6543 23.6675 23.9365 5303 53.0531195 -27.8296973 24.7686 24.4843 23.8944 23.6399 22.3425 23.0299 5348 53.0534055 -27.8360254 27.249 26.8999 26.7628 26.8751 25.5407 25.5783 5383 53.0536962 -27.7590808 26.5347 26.4772 26.3793 26.3379 25.1899 25.1677 5396 53.0538073 -27.7499664 25.7408 25.166 24.5505 23.9322 21.854 21.9562 5515 53.0547155 -27.7597595 23.5065 23.3046 22.9061 22.5626 21.8789 22.2081 5518 53.0547372 -27.7986369 25.3127 24.054 23.2152 22.9512 21.9585 22.3313 5549 53.0549288 -27.8155717 24.0702 23.1853 22.5323 22.3388 21.6356 21.9845 5762 53.0566599 -27.7217222 25.776 25.6101 25.3768 25.0498 23.6158 23.7097 5851 53.0573158 -27.8095195 26.4915 26.336 26.1181 25.7786 24.4486 24.8433 5907 53.0577704 -27.7960226 26.2622 25.9438 25.485 25.1401 24.2676 24.7536 5939 53.0580388 -27.8000818 26.1634 25.5366 25.3974 25.3978 23.9916 24.0359 5987 53.0583483 -27.6878254 26.6364 25.8933 25.6287 25.4807 23.4961 23.4722 6045 53.0587365 -27.7975520 24.5785 24.3302 23.7052 23.3356 22.293 22.7237 6083 53.0589668 -27.8210247 24.3442 24.0152 23.3889 23.0776 22.1816 22.6368 6091 53.0590454 -27.7335640 26.3656 25.868 25.0747 24.897 24.055 24.5162 6175 53.0596280 -27.7118881 25.4927 24.801 23.9829 23.2801 20.842 20.9217 6186 53.0597059 -27.8015439 26.0975 25.9471 25.486 25.149 24.4874 24.9705 6206 53.0598658 -27.7162858 25.8742 24.8493 23.7981 23.1448 21.12 21.4528 6266 53.0602724 -27.8134998 23.4747 22.6938 22.4357 22.2486 22.1514 22.3804 206 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 6273 53.0603191 -27.8237352 26.0191 25.8337 25.2061 25.0326 24.8934 25.7002 6286 53.0603864 -27.7516681 26.4063 26.1281 26.0376 25.9796 24.6253 24.2679 6354 53.0608161 -27.7914375 26.4943 26.0788 25.9963 26.1482 24.6286 24.6389 6432 53.0614832 -27.6962618 26.0581 25.7706 25.6606 25.2984 24.1292 24.093 6454 53.0616173 -27.8462455 24.9178 24.2241 24.1267 24.1543 23.8958 23.7526 6560 53.0622344 -27.7010725 25.6518 25.4732 25.439 25.3554 24.3723 24.4545 6581 53.0623409 -27.7651350 23.8137 23.7399 23.4919 23.1627 22.5259 22.6158 6596 53.0624407 -27.7355465 25.7964 24.9622 24.8044 24.7066 22.8175 22.8415 6599 53.0624543 -27.8839820 23.4385 23.3619 23.2761 22.8117 21.9118 22.0052 6609 53.0625277 -27.8845599 26.4787 26.2757 26.3352 25.7666 24.3956 24.4051 6634 53.0626816 -27.7072908 25.5211 25.3605 25.3301 25.1286 23.3599 23.283 6647 53.0627426 -27.8450141 25.0838 24.9877 24.8314 24.5575 22.6703 22.6172 6648 53.0627436 -27.8216160 25.3174 24.9209 24.2708 24.2092 24.0193 24.4185 6650 53.0627673 -27.7892206 25.4246 25.2201 25.1309 25.0237 23.531 23.6538 6770 53.0636390 -27.8373463 26.6062 25.8704 25.0663 24.8903 24.0477 24.5613 6778 53.0636845 -27.7656247 26.8675 26.623 26.1261 25.507 23.9216 24.0726 6783 53.0637230 -27.7568204 27.0127 26.7394 26.6488 26.6578 25.3205 25.3284 6895 53.0644659 -27.7753761 25.3319 24.0466 23.134 22.8014 20.1932 20.2195 6951 53.0648277 -27.7166206 23.2883 22.3769 22.0577 21.964 22.2081 22.5506 6978 53.0650004 -27.7326926 24.8682 24.6216 24.5878 24.6443 23.97 24.0745 6987 53.0650570 -27.6870680 25.6208 25.2981 25.1054 24.9398 22.9761 22.9642 6997 53.0651192 -27.6898442 25.2752 24.5942 24.4348 24.4503 23.0945 22.9933 7019 53.0652820 -27.6902146 25.6051 25.4062 24.7273 24.5093 23.8125 24.4527 7041 53.0654199 -27.6878477 25.2783 24.6762 23.9084 23.4218 21.0822 21.2664 7046 53.0654690 -27.6963936 23.5496 21.9117 21.1463 20.8866 21.3534 21.839 7066 53.0656542 -27.7678680 24.9832 24.5089 23.995 23.6594 21.0219 20.8379 7089 53.0657639 -27.7361758 27.2831 26.4343 26.3532 26.4734 25.071 24.9251 7100 53.0658292 -27.8901978 24.7638 23.3361 22.2357 21.806 20.0015 20.4054 7127 53.0659586 -27.7309059 24.6408 23.9708 24.4797 24.0015 24.4564 24.7891 7133 53.0660665 -27.6877866 26.0918 24.2948 22.8751 22.3639 22.6853 23.1836 7135 53.0660700 -27.7203376 27.0737 26.4149 26.1986 25.9136 22.963 22.7975 207 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 7165 53.0662755 -27.8118457 26.4365 26.4645 25.9006 25.558 24.6514 25.0544 7250 53.0668846 -27.8377442 25.5202 24.7503 23.9504 23.7559 22.749 23.163 7292 53.0671579 -27.8666991 25.9804 25.3457 24.6544 24.4029 23.5198 23.9109 7369 53.0677289 -27.8418098 27.0514 26.3655 25.5917 25.4325 24.5585 25.0309 7425 53.0681501 -27.8235188 26.5999 26.162 26.0734 25.9118 24.0976 24.1619 7467 53.0684596 -27.7282607 26.4423 25.6925 25.5107 25.3789 22.5978 22.2745 7504 53.0687334 -27.7469545 23.8931 23.3379 22.5831 22.2085 20.1292 20.418 7624 53.0695659 -27.7444353 25.1624 24.5961 23.551 22.9421 21.141 21.5131 7629 53.0696016 -27.6931275 25.1645 25.0255 24.6302 24.436 22.0171 21.8235 7630 53.0696044 -27.7772635 27.4003 26.8032 26.6457 26.4935 24.7614 23.8962 7649 53.0697308 -27.7191384 26.6628 26.4592 26.4638 26.3392 25.6556 25.3402 7786 53.0706082 -27.7553644 25.8458 25.313 24.5969 23.7761 21.1427 21.2536 7867 53.0710660 -27.8227406 22.0545 20.3288 19.4992 19.1641 18.5496 18.744 7916 53.0713817 -27.8774627 24.7681 24.6054 24.0796 23.6819 22.7853 23.2467 7925 53.0714146 -27.7770171 26.6543 26.4189 26.4843 26.1812 24.3677 24.5945 7950 53.0715123 -27.9039369 27.0319 26.5559 26.1161 25.8778 25.4298 25.1201 7973 53.0716248 -27.8148620 24.8147 24.6465 24.4649 24.3014 22.9929 23.0118 8003 53.0718191 -27.9025250 24.3758 23.6211 22.6845 22.1942 20.2888 20.6782 8108 53.0724480 -27.7580853 24.7773 24.5128 24.2507 23.9398 22.5747 22.5333 8166 53.0727705 -27.6980126 25.7282 25.1123 24.9528 24.8132 22.7453 22.6639 8170 53.0727870 -27.7623241 25.7451 25.0847 24.324 24.1192 23.4509 23.9119 8176 53.0728255 -27.6933485 25.1597 24.9724 24.6973 24.4556 22.6733 22.5618 8207 53.0729904 -27.7267992 24.6507 24.4693 24.3475 24.1457 22.8487 22.8608 8226 53.0731563 -27.6931681 25.8904 25.5863 24.9586 24.7819 24.3895 24.9915 8259 53.0733013 -27.7871115 26.5021 25.8237 25.5107 25.4489 23.2579 23.3727 8282 53.0734213 -27.7159527 23.8109 23.0778 22.3702 22.1479 20.8165 21.1902 8335 53.0736528 -27.7441536 25.3942 25.0679 24.2844 23.944 22.9055 23.425 8434 53.0742131 -27.7754049 25.5633 24.9934 24.3423 24.318 24.2742 24.9144 8440 53.0742610 -27.8210939 23.7466 23.7313 23.4803 23.3622 22.7851 23.1496 8562 53.0751366 -27.8422336 25.9229 25.3775 24.8329 24.9344 24.5918 24.9439 8563 53.0751387 -27.9068562 26.1501 25.2387 24.4597 24.3074 23.5106 23.9103 208 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 8581 53.0752682 -27.8885905 25.9747 25.1906 25.0084 24.6662 22.1105 22.0613 8635 53.0756701 -27.8903139 24.4543 23.4205 22.9701 22.7673 22.6373 23.0026 8857 53.0768741 -27.7655254 25.036 22.7573 21.2693 20.763 19.1596 19.6472 8946 53.0775538 -27.7847384 24.3386 24.2328 23.8545 23.4431 21.7748 21.8398 8969 53.0777284 -27.8692820 25.5784 23.599 22.205 21.7263 20.3415 20.8517 9000 53.0779143 -27.8221573 25.9789 24.9312 23.5897 22.8265 19.9634 20.1777 9050 53.0781882 -27.7334556 25.7779 25.4357 24.7032 24.6 24.0824 24.6034 9171 53.0787970 -27.6937487 25.3063 25.0511 25.0644 25.0983 24.0207 23.869 9187 53.0789145 -27.7996397 25.148 24.7128 24.0265 23.7362 22.1437 22.498 9188 53.0789164 -27.7094494 26.5552 26.3781 25.8913 25.5158 23.0013 22.931 9211 53.0791793 -27.6909391 26.2902 26.1797 26.0159 25.8747 23.6197 23.611 9244 53.0793363 -27.8622067 22.8951 21.9331 21.4943 21.2854 21.3732 21.5424 9280 53.0795677 -27.8973651 26.2201 26.1936 26.0726 25.6799 24.5561 24.761 9304 53.0797105 -27.7078072 25.3934 25.2791 25.0517 24.5352 23.3548 23.4352 9361 53.0800296 -27.7473881 24.9047 24.2422 23.2512 22.6393 20.5748 20.8631 9362 53.0800306 -27.7520976 25.0129 24.3818 23.7583 23.6738 23.2539 23.772 9397 53.0802248 -27.8976008 25.3857 25.3567 25.1859 24.8671 23.7551 23.7288 9399 53.0802348 -27.7766689 25.5269 25.5099 25.4907 25.6801 25.4688 25.2701 9489 53.0809145 -27.8308311 25.8565 25.611 25.0721 24.9482 24.483 25.0506 9553 53.0813008 -27.9120161 24.8965 23.988 23.6975 23.6172 23.785 24.2213 9771 53.0825943 -27.7541361 24.785 24.7298 24.5176 23.997 22.8956 23.0763 9837 53.0831774 -27.7471694 24.248 23.6961 22.7924 22.5515 21.5535 22.0034 9929 53.0837175 -27.7484457 26.9787 26.5475 26.273 26.27 23.5346 23.384 9935 53.0837462 -27.6795444 23.499 22.709 22.2717 22.0777 22.0315 22.3614 9950 53.0838628 -27.7600836 24.9418 24.6179 23.8633 23.6823 23.2772 25.3091 10002 53.0841943 -27.9356849 25.4741 25.1476 25.1194 25.1331 24.2985 24.3196 10090 53.0847182 -27.9180034 26.0611 25.8261 25.7061 25.9271 25.382 25.1347 10097 53.0847779 -27.7030838 25.7158 25.1398 25.2032 24.7047 23.7732 24.2519 10169 53.0853058 -27.8398735 26.4192 25.842 25.3957 25.2799 23.355 23.1055 10249 53.0858085 -27.6867495 24.0961 23.8919 23.7966 23.6518 21.8849 21.7519 10265 53.0859043 -27.6746131 25.4115 25.4749 25.0916 24.8646 24.4948 25.0278 209 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 10337 53.0863139 -27.6894700 25.0974 24.934 24.6448 24.2159 22.4803 22.4878 10344 53.0863400 -27.8187300 25.5543 25.159 25.1188 25.1529 24.6387 24.7136 10545 53.0876633 -27.8246730 25.2985 24.6893 23.9395 23.7651 22.7208 23.2742 10586 53.0878596 -27.7376358 25.975 25.9014 25.8866 25.8903 24.9247 25.1728 10631 53.0881515 -27.8238262 24.9356 24.7538 24.6841 24.6811 23.3933 23.3561 10689 53.0885544 -27.8584210 26.0007 25.0647 24.5989 24.448 24.1999 24.6004 10698 53.0886082 -27.8248557 24.2341 23.9719 23.4529 23.3138 22.8794 23.4318 10760 53.0889921 -27.6738992 24.0989 23.8899 23.0214 22.1326 20.067 20.2887 10844 53.0894610 -27.7374277 26.4448 25.7273 25.7856 25.545 23.8992 23.6833 10852 53.0895348 -27.9310159 25.8945 25.6936 25.1838 24.6699 23.5822 24.2276 10875 53.0896232 -27.8999037 25.7663 24.4987 23.7775 23.3337 21.0231 21.1825 10876 53.0896241 -27.6791698 23.9241 23.9322 23.5511 23.2417 22.577 22.9357 10994 53.0903212 -27.9363521 25.0844 24.5093 23.8017 23.636 22.8132 23.2733 11209 53.0915136 -27.7720220 26.3635 26.0239 25.4471 25.2463 24.3431 24.5556 11210 53.0915156 -27.7038938 24.2743 24.0695 23.4785 23.0912 22.127 22.4378 11300 53.0919907 -27.7354664 26.0567 25.9899 25.8489 25.8342 24.1457 24.5489 11381 53.0925505 -27.7408123 26.7391 26.5996 26.5418 26.2531 23.6999 23.7133 11396 53.0926779 -27.7639888 23.8109 23.1837 22.4592 22.2606 21.5317 21.9606 11574 53.0936691 -27.7821512 25.3798 24.5288 23.7151 23.482 22.2363 22.7058 11577 53.0937063 -27.9248215 25.6757 24.8544 24.5525 24.5854 22.9933 22.9942 11592 53.0938090 -27.7033626 25.1976 25.0589 24.7562 24.196 23.1769 23.3834 11696 53.0944359 -27.7458759 24.9762 24.5209 23.8342 23.7068 23.3466 23.7119 11724 53.0945869 -27.8297687 25.5435 25.4448 25.3793 25.0435 24.3835 24.2901 11819 53.0951144 -27.8233102 26.3397 25.6364 25.4017 25.5046 24.6842 24.7623 11848 53.0952947 -27.9039774 26.5904 25.7161 25.3759 25.0581 21.7985 21.722 11976 53.0961461 -27.9167785 26.6051 26.2891 25.9984 25.6555 23.5892 23.6142 12029 53.0964861 -27.9250503 25.1105 24.9945 24.5509 24.395 23.7713 24.0027 12060 53.0965924 -27.8103445 26.7286 26.1986 26.1829 26.0998 25.2843 25.1972 12141 53.0971388 -27.7275896 25.7309 25.6067 25.4131 25.0758 23.864 23.8828 12146 53.0971884 -27.7422576 25.3506 25.1227 24.7315 24.09 22.6852 22.854 12362 53.0986205 -27.9451047 26.7155 26.4996 26.348 25.6618 24.4479 24.753 210 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 12396 53.0988450 -27.8015544 25.4011 25.1561 25.0883 24.9358 23.4095 23.4775 12461 53.0991529 -27.7108190 26.0769 25.9179 25.2289 24.9368 24.0634 24.6842 12680 53.1004056 -27.7597602 25.3772 24.588 24.1738 24.1026 24.3059 24.6874 12763 53.1008577 -27.8153005 26.097 25.8231 25.7502 25.672 23.8979 24.1739 12783 53.1009757 -27.7795956 26.3484 26.081 25.8873 25.798 23.9404 23.8375 12797 53.1010419 -27.8535797 25.6747 25.5232 24.8972 24.7416 24.2551 24.7879 12832 53.1011855 -27.8184357 27.5465 27.0292 27.0061 27.0061 24.0457 23.9473 12869 53.1013658 -27.8603087 26.5337 26.2982 26.3608 26.1207 24.2658 24.2433 13064 53.1025095 -27.6723978 25.3832 24.2089 23.2212 22.5607 20.2397 20.4559 13084 53.1026265 -27.8388907 26.9725 26.6917 26.4633 26.5065 24.9619 24.8946 13136 53.1028786 -27.9397591 26.3975 26.387 26.3426 26.2801 23.9856 23.8469 13162 53.1030428 -27.7808324 27.1421 26.723 26.751 26.852 24.8871 25.0807 13264 53.1036122 -27.7706326 25.5764 25.3759 25.3974 25.3395 24.3272 24.3051 13320 53.1039186 -27.8604201 26.3085 25.9543 25.7361 25.5421 23.2504 23.0901 13343 53.1040638 -27.8227331 26.7146 26.2494 25.5979 25.4186 24.9255 25.2964 13344 53.1040690 -27.6693713 25.4824 25.3864 24.7064 24.4472 24.1298 24.354 13386 53.1043019 -27.7464760 25.7823 25.6005 24.8522 24.448 21.1929 21.0087 13408 53.1044181 -27.7285105 25.1806 24.5791 23.7127 23.5049 22.5798 23.0593 13439 53.1045629 -27.7342140 19.7448 18.5148 17.9775 17.7138 17.9788 18.4359 13504 53.1049310 -27.9397588 24.2175 24.1412 23.7423 23.4265 22.7059 23.1182 13532 53.1050921 -27.6749488 25.0403 24.8728 24.3244 24.1508 23.7566 24.3112 13594 53.1054254 -27.8338755 26.2807 26.2973 26.029 25.6675 24.553 24.748 13659 53.1057752 -27.8697987 24.5412 24.4421 24.2417 23.8614 23.1175 23.2401 13675 53.1059058 -27.7384158 25.6917 24.9229 24.3338 24.1906 24.0491 24.5301 13724 53.1061689 -27.8698943 24.2838 24.2562 24.1922 23.7924 23.2481 23.2713 13802 53.1065932 -27.7580413 25.9757 25.3057 24.6698 24.5717 24.2664 24.5339 13804 53.1065995 -27.6901939 25.245 24.4839 23.8999 23.6801 23.3753 23.632 13838 53.1068236 -27.6938794 26.6148 26.0663 25.8658 25.656 23.3412 23.2979 13840 53.1068364 -27.8173386 26.3936 26.0438 25.2068 24.8624 24.1892 24.5116 13906 53.1071984 -27.8142928 26.2202 26.0678 26.2316 26.1137 25.4026 25.2721 13910 53.1072170 -27.7922500 26.5381 26.0678 25.6819 25.3152 24.7549 25.3431 211 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 13913 53.1072309 -27.6932305 26.5529 26.1944 25.3498 25.1483 24.2416 25.1429 13941 53.1073832 -27.7498124 24.1402 23.6158 23.0214 22.6661 21.4995 21.9553 14068 53.1080652 -27.7020318 25.4299 25.2862 25.1824 25.1353 23.5493 23.7045 14081 53.1081351 -27.6962830 25.8283 25.628 25.4417 25.2358 23.4815 23.4832 14117 53.1082932 -27.6952608 25.4796 24.8412 24.7005 24.783 23.6971 23.8584 14131 53.1083536 -27.8701873 26.0874 25.9211 25.7496 25.7897 24.4686 24.5301 14135 53.1083706 -27.8925768 24.7547 23.9508 23.5104 23.411 23.4406 23.7279 14155 53.1084600 -27.8632548 24.2755 24.1038 23.6668 23.1643 21.9016 22.0414 14221 53.1087712 -27.8807130 25.189 25.0312 24.9703 24.9162 23.6514 23.6778 14236 53.1088508 -27.7254343 26.5639 26.1328 25.7643 25.7072 24.0269 24.2782 14259 53.1089870 -27.8940932 26.7884 26.7187 26.0796 25.9055 24.1623 25.1644 14277 53.1090563 -27.7223834 25.8599 25.691 25.3482 25.1024 24.0487 24.4961 14316 53.1092287 -27.6982887 26.2842 26.15 25.7321 25.2667 24.4395 25.1185 14417 53.1095988 -27.6742146 23.3316 22.986 22.3858 22.0828 20.4352 20.6804 14441 53.1097514 -27.7026751 23.7417 23.5388 22.8957 22.6768 21.9809 22.4616 14447 53.1098183 -27.6757262 24.2115 23.692 22.8717 22.3763 21.2507 21.862 14488 53.1099997 -27.7078331 24.7623 24.4935 24.0401 23.6078 21.0165 20.8587 14537 53.1102693 -27.7059714 26.4276 26.3009 25.8932 25.8849 23.2397 23.5223 14547 53.1103252 -27.6980659 26.3283 26.1227 25.5117 24.8974 22.4294 22.474 14586 53.1105088 -27.8073917 26.6521 25.9669 25.7054 25.6562 24.1629 24.2533 14713 53.1111153 -27.7996539 23.5635 22.7788 22.0414 21.8369 20.5584 20.9304 14798 53.1116278 -27.6915502 25.199 24.5772 24.3598 24.2638 22.6898 22.6532 14821 53.1117077 -27.6990119 23.0683 23.0112 22.907 22.7925 21.7622 21.7171 14848 53.1118186 -27.7470987 26.9471 26.473 26.4679 26.2428 24.7747 24.8022 14907 53.1120508 -27.8687111 25.8707 25.1136 24.6685 24.5541 24.4779 24.6524 14961 53.1123561 -27.8171149 25.2018 24.978 24.8417 24.7636 23.3298 23.366 15036 53.1127751 -27.7538884 26.6909 26.2373 26.0467 25.8798 23.7503 23.7747 15079 53.1130222 -27.7947754 26.0218 25.9504 25.1895 25.0502 24.6421 25.1619 15112 53.1131963 -27.7671218 27.3603 27.0759 27.0265 27.0157 23.7081 24.0924 15143 53.1133193 -27.7550310 25.7733 25.7397 25.7166 25.6562 25.0389 24.7867 15146 53.1133277 -27.8639962 24.2621 24.0604 23.7387 23.4324 23.2849 23.5529 212 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 15203 53.1136137 -27.7774612 24.9658 24.7822 24.5886 24.5442 23.0011 22.9775 15280 53.1139886 -27.8837214 26.3089 24.6052 23.7823 23.5568 24.1651 24.6195 15325 53.1142108 -27.8318568 24.1504 24.1836 24.1693 23.8457 23.4076 23.5278 15385 53.1145204 -27.7381764 25.6774 25.2097 24.4928 24.2318 22.8552 23.5583 15402 53.1145781 -27.6884762 27.1764 26.0714 25.504 25.558 24.4664 24.1739 15477 53.1149464 -27.7675584 23.5592 22.0569 20.9307 20.5208 18.7559 19.1888 15528 53.1152410 -27.7071386 26.1427 26.233 25.7182 25.1206 24.0819 24.4685 15570 53.1154517 -27.7535290 26.2834 26.1335 25.3011 25.0309 23.9778 24.2039 15859 53.1170099 -27.9050395 26.2378 25.5134 24.7805 24.6452 24.2295 24.8986 15908 53.1173632 -27.7801124 25.3756 25.032 24.7678 24.6061 22.5258 22.4798 15968 53.1177740 -27.8304754 22.763 21.6565 21.174 20.9743 21.1967 21.6279 16021 53.1180256 -27.8852454 26.5955 26.3684 25.9461 25.5527 24.5854 25.0916 16119 53.1184867 -27.7843528 24.4085 22.6886 21.3166 20.8514 19.4472 19.9816 16192 53.1188308 -27.8591559 27.3013 26.7515 26.8157 26.6641 25.5206 25.368 16263 53.1191671 -27.7625504 26.5477 26.5971 26.6604 26.5309 25.1249 25.1745 16282 53.1192714 -27.7408974 25.6314 25.4365 24.8983 24.7347 23.6893 24.5965 16335 53.1195725 -27.7867087 26.9798 26.6641 26.2997 26.097 23.6386 23.7706 16363 53.1196495 -27.6806144 23.7149 23.2942 23.0793 23.0929 23.7533 24.4304 16411 53.1198485 -27.7147847 25.6938 25.3597 25.1809 25.1115 23.4746 23.4818 16448 53.1200352 -27.8933158 25.8383 25.3896 24.5269 24.1758 22.7265 23.1018 16550 53.1206452 -27.8241265 26.0139 25.8202 25.6463 25.4752 23.7203 23.7701 16559 53.1206892 -27.7822150 24.2268 22.5077 21.764 21.5207 22.0036 22.458 16570 53.1207345 -27.9111067 26.5799 26.386 25.8752 25.2991 23.9893 24.3724 16585 53.1207762 -27.6684055 25.2668 24.5262 23.6863 23.4768 22.7872 23.2588 16605 53.1208376 -27.8617359 27.2378 26.425 26.2571 26.2785 24.8135 24.9332 16655 53.1211429 -27.6931527 21.9457 21.1211 20.8316 20.6088 20.6392 20.832 16656 53.1211456 -27.6980689 25.8864 25.278 24.7761 24.3743 21.5754 21.4918 16735 53.1215773 -27.7233974 25.865 25.6936 25.5803 25.4105 24.4409 24.4278 16743 53.1216049 -27.7805365 26.158 25.9609 25.8735 25.7039 23.9967 23.9834 16747 53.1216220 -27.7370074 24.9669 24.8377 24.7654 24.5222 23.3407 23.4056 16869 53.1223468 -27.7841688 26.017 25.2689 25.0145 24.9481 24.2134 24.9463 213 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 16951 53.1227418 -27.7353881 23.2898 22.333 21.8896 21.7474 21.5155 21.7878 17025 53.1231250 -27.6865909 25.3959 25.4042 24.9957 24.4864 23.7862 24.2213 17033 53.1231548 -27.7667117 23.5301 22.6463 22.3433 22.1589 22.2549 22.512 17093 53.1234985 -27.8293009 24.6188 24.405 24.0408 23.5199 22.3405 22.6093 17134 53.1237302 -27.7214458 26.3675 26.0937 25.4926 25.1645 22.1755 22.0089 17176 53.1239701 -27.8940950 26.959 27.0109 27.0702 27.1009 23.7149 23.5694 17218 53.1241589 -27.8916932 26.6332 26.252 25.9542 25.8197 24.2185 24.3708 17233 53.1242114 -27.8896716 25.6609 25.2898 24.6435 24.1764 23.383 23.9627 17312 53.1246721 -27.9105856 25.4686 25.1886 25.0625 25.0058 23.43 23.4645 17360 53.1249009 -27.8750833 19.2795 18.551 18.059 17.7789 18.8328 19.3367 17406 53.1251187 -27.7298016 21.8632 21.0267 20.1289 19.8377 18.6901 19.1546 17418 53.1251555 -27.7209043 25.2899 24.2945 23.8041 23.5898 24.0624 24.339 17558 53.1258985 -27.7512762 22.5857 22.0722 21.6851 21.4627 20.4479 20.5502 17584 53.1260175 -27.7060457 26.1554 25.9077 25.7691 25.6025 24.1798 24.2433 17666 53.1264702 -27.9001723 27.0154 26.3733 26.3391 26.1977 24.7381 24.6767 17724 53.1267805 -27.8612246 24.1972 23.4879 22.6054 22.3421 20.9152 21.3272 17769 53.1270533 -27.7095447 24.8582 24.6634 24.2218 24.0803 23.9238 24.6493 17899 53.1277220 -27.8260226 25.8766 25.6786 25.0638 24.8006 23.636 23.9975 17950 53.1280179 -27.7173277 26.6133 25.7778 25.6319 25.566 23.9583 24.0096 17968 53.1280983 -27.8848400 25.3498 24.6758 24.3558 24.32 24.6303 25.1745 17974 53.1281288 -27.7292719 24.1046 24.0802 24.0255 23.7531 23.0561 23.0507 18008 53.1282790 -27.7770572 25.5386 25.4324 24.889 24.248 23.0541 23.3902 18072 53.1285916 -27.7552305 25.8668 25.829 25.8678 26.0738 24.113 24.3227 18133 53.1288235 -27.7804180 25.7967 25.0767 24.254 23.5014 20.695 20.8533 18174 53.1290766 -27.7545388 24.9289 24.7867 24.1482 23.7264 22.6817 23.0182 18427 53.1304553 -27.7758811 25.6789 24.5233 24.2221 24.2202 22.9963 23.0572 18453 53.1305517 -27.8693338 26.2892 26.1684 26.2121 26.25 25.3688 25.0932 18468 53.1306048 -27.8792951 26.4894 26.3313 26.2383 26.1514 25.2083 24.9634 18529 53.1309564 -27.7953371 27.242 26.6524 26.4806 26.5304 25.274 25.6421 18607 53.1313553 -27.8672584 26.4448 26.3091 25.8249 25.3557 24.2352 24.146 18642 53.1315563 -27.8554434 26.0323 25.466 25.1453 24.8313 24.6798 24.9523 214 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 18658 53.1316235 -27.7708730 25.4595 24.1708 23.8047 23.7999 23.214 23.0044 18678 53.1317771 -27.7535793 25.7758 25.5533 24.8831 24.6131 23.8628 24.642 18760 53.1322145 -27.9198433 26.4548 25.9663 25.0818 24.9471 23.9718 24.5623 18774 53.1323045 -27.7366706 25.5211 24.712 24.3423 24.2269 24.3815 24.8895 18791 53.1323594 -27.6676998 26.4287 26.4624 25.9739 25.6154 24.885 24.9944 19004 53.1336239 -27.9420211 26.082 25.0454 24.6293 24.4234 24.3508 24.9278 19038 53.1338005 -27.7819011 26.4276 25.4783 25.2386 25.1986 23.5857 23.5915 19201 53.1347008 -27.7007144 22.1619 20.2626 18.7 18.0575 18.239 18.6509 19265 53.1350820 -27.9427075 26.6983 26.4508 25.7007 25.1856 24.0394 24.3846 19421 53.1358841 -27.8879612 24.5486 24.1408 23.3851 23.0036 21.8059 22.2021 19557 53.1366669 -27.6577648 26.8826 25.629 25.3565 25.2913 24.7354 24.5508 19591 53.1368993 -27.7350227 25.4414 25.2487 24.7457 24.3814 23.3584 23.7531 19636 53.1371634 -27.7541788 24.8376 23.921 22.9175 22.5621 20.9663 21.3659 19779 53.1379599 -27.8064064 26.1661 25.7965 25.1515 25.0305 24.4621 24.8763 19792 53.1380457 -27.8096611 25.724 24.9994 24.2598 24.0911 23.7359 24.3128 19813 53.1381546 -27.7180978 24.9721 24.4773 24.3552 24.352 22.5539 22.8019 19825 53.1382239 -27.8429239 24.7748 22.7466 21.0019 20.3085 20.4545 20.8436 19917 53.1388015 -27.6695396 26.2146 26.0796 25.755 25.3736 24.3736 24.7026 19933 53.1389508 -27.8869142 25.8767 24.4213 23.3592 22.9329 20.8032 21.1868 19976 53.1391213 -27.7303011 21.0292 20.3682 20.0023 19.8954 20.123 20.4973 19999 53.1392651 -27.7379931 26.3294 25.4737 24.6592 24.4495 23.7721 24.2664 20030 53.1393998 -27.7867750 25.9171 25.5849 24.9436 24.2916 21.9772 22.0311 20044 53.1394887 -27.8956462 26.0286 25.9464 25.2134 25.0163 24.3392 25.1396 20158 53.1401304 -27.9345699 25.2645 24.3402 24.0196 23.8154 23.9347 24.2715 20192 53.1403263 -27.7571821 25.5011 25.3574 25.1881 24.9614 23.6943 23.6736 20212 53.1404584 -27.7809222 27.049 26.5792 25.8564 25.6748 24.5338 24.9938 20221 53.1404843 -27.6615117 26.9245 26.3267 26.2353 26.0671 23.9879 24.0708 20230 53.1405570 -27.8771933 26.6918 26.425 25.9669 25.359 23.7142 24.0073 20270 53.1407466 -27.8039884 24.7406 24.6119 24.6332 24.7095 23.94 24.2122 20285 53.1407999 -27.6858889 26.4871 26.5175 26.3892 26.1303 24.6195 25.1058 20331 53.1410276 -27.8721211 25.6421 24.8747 24.5581 24.5442 24.0669 24.1074 215 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 20466 53.1417622 -27.8685037 25.6432 25.5174 24.8396 24.4911 23.5328 23.8639 20483 53.1418485 -27.8413693 24.2017 23.9815 23.5095 22.9544 20.3892 20.2221 20536 53.1421191 -27.7866994 22.1481 21.1838 20.759 20.6029 20.5671 20.7401 20539 53.1421295 -27.8531813 24.9373 24.1711 23.9111 23.7291 23.9129 24.197 20602 53.1424313 -27.7762952 26.6342 26.4603 26.261 25.7933 24.6642 24.6535 20632 53.1425827 -27.8950654 25.8586 24.7328 23.6948 23.2668 21.0976 21.5119 20666 53.1427737 -27.8481157 27.2294 26.9786 26.8338 26.69 25.587 25.207 20682 53.1428501 -27.7069256 23.7291 23.0108 22.0176 21.2091 19.1798 19.416 20817 53.1436506 -27.8879384 26.1568 25.5307 25.4526 25.4487 23.8336 23.7822 20867 53.1439344 -27.7797304 26.26 26.0825 25.9418 25.855 24.918 24.7195 20874 53.1440073 -27.9287703 24.3229 23.7873 22.8776 22.3906 21.0762 21.3946 20885 53.1440631 -27.9231418 26.1456 26.102 26.0613 25.7353 24.4325 24.2983 20886 53.1440660 -27.7346051 25.7912 25.0191 23.9422 23.54 21.7151 22.0915 20916 53.1442039 -27.7067047 23.6745 22.2748 21.4177 20.9817 19.2617 19.3572 20925 53.1442445 -27.7690586 26.2998 25.9218 25.787 25.7663 24.5726 24.7568 20969 53.1444959 -27.7280744 26.0103 25.4912 25.3607 25.3263 23.975 23.9577 20973 53.1445353 -27.6903112 25.3908 25.1721 25.0903 24.9602 23.4311 23.4304 20986 53.1446353 -27.6684999 26.196 26.0877 25.9726 25.6955 24.6642 24.7507 20998 53.1446891 -27.8273257 25.1862 24.8462 24.2573 23.6727 22.2474 22.4312 21008 53.1447655 -27.9284390 25.1291 24.7429 24.3013 23.9975 21.8354 21.832 21029 53.1448638 -27.7434150 25.7119 25.206 24.5812 24.5914 24.2038 24.801 21130 53.1454119 -27.8419961 26.4575 26.0431 25.4471 25.2763 24.902 25.3905 21153 53.1454935 -27.9038384 21.1967 20.2873 19.9166 19.7357 19.7037 19.7755 21254 53.1459842 -27.8257357 25.8141 25.5303 25.3624 25.2094 23.409 23.245 21262 53.1460354 -27.7915877 27.1142 26.4953 26.2602 26.2405 25.5039 25.5839 21289 53.1461707 -27.8919495 25.2938 24.875 24.0698 23.8086 22.5795 23.0219 21292 53.1461773 -27.7710330 24.4382 24.2477 23.826 23.1903 21.7593 21.8977 21336 53.1464535 -27.8872329 25.6592 25.5438 25.1268 24.6219 23.3698 23.6303 21361 53.1465840 -27.8767140 24.0146 23.581 22.835 22.6376 22.0798 22.5066 21387 53.1467045 -27.9045617 23.8925 23.4504 22.9114 22.8608 22.1886 22.5246 21419 53.1468992 -27.8513321 25.6726 24.5283 23.3713 22.924 21.4229 21.896 216 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 21450 53.1470201 -27.7700560 25.2398 24.4861 23.9142 23.7859 23.3532 23.771 21595 53.1477855 -27.7200724 27.1602 26.8917 26.1455 25.9297 24.9558 25.1949 21597 53.1478033 -27.9399749 25.9832 25.5853 25.1357 24.9471 22.66 22.5325 21612 53.1478985 -27.6877008 26.2756 26.1692 26.2431 26.1119 25.003 25.0161 21621 53.1479229 -27.7739666 22.549 22.2536 21.7145 21.2338 19.6904 19.8685 21643 53.1480375 -27.6837162 25.4955 25.4349 25.2208 24.7436 23.7326 23.891 21675 53.1482425 -27.8440983 26.8559 26.5014 26.3235 26.226 24.1419 23.9918 21781 53.1488303 -27.9376066 24.5025 24.0783 23.2961 22.7346 21.2221 21.4941 21794 53.1488901 -27.7775042 27.3911 26.7027 26.1128 25.6391 22.2595 22.1952 21810 53.1489575 -27.7996805 24.7001 22.2844 20.879 20.4009 18.9198 19.4571 21820 53.1490150 -27.7819436 25.6582 25.4597 25.0883 24.8367 22.4772 22.3815 21909 53.1495143 -27.8048124 26.0157 25.4134 25.2667 25.1828 23.2266 23.1156 21919 53.1495648 -27.6756916 25.8203 25.6863 25.4964 25.3325 23.7555 23.7921 22028 53.1502468 -27.7522383 26.1345 24.6116 23.8428 23.6324 24.2243 24.7844 22063 53.1505464 -27.9206154 26.126 25.7193 25.5671 25.4926 22.9251 22.9048 22077 53.1506358 -27.9024465 22.7083 22.223 22.1233 22.0133 22.4644 22.726 22113 53.1508065 -27.9054623 25.4504 23.632 22.6731 22.347 22.7276 23.061 22170 53.1511145 -27.9316070 25.8466 24.798 24.5734 24.4182 22.5725 22.5924 22197 53.1512489 -27.7559362 25.0653 24.7192 24.6392 24.5667 23.3958 23.4603 22220 53.1513548 -27.7052577 26.7216 26.5367 26.0752 25.7046 24.9671 25.362 22305 53.1517125 -27.9256732 26.6819 26.4666 25.7039 25.507 23.6664 23.6706 22338 53.1518202 -27.7757350 26.8931 27.0016 26.7925 26.7002 23.6002 23.0985 22346 53.1518402 -27.7214986 25.3547 25.2573 24.954 24.638 23.0246 23.1123 22376 53.1519525 -27.7412868 26.0567 25.8017 25.7242 25.2107 23.5171 23.5709 22477 53.1524776 -27.8419569 25.0153 24.5644 23.8842 23.7041 23.1109 23.412 22552 53.1529180 -27.8057553 26.4007 26.4038 26.2258 26.1317 24.8651 24.6545 22628 53.1534164 -27.8586368 24.3951 24.3209 23.923 23.4324 22.5554 22.7836 22688 53.1537499 -27.8985816 26.1568 26.192 26.1051 25.8022 24.338 24.5965 22721 53.1539184 -27.8416014 26.8165 26.6013 26.5905 26.6064 24.9424 25.0308 22747 53.1540180 -27.9086904 25.3917 24.9732 24.3026 24.0889 23.4726 24.0788 22765 53.1541135 -27.9350053 25.7274 25.5811 25.3844 25.2104 24.226 24.1214 217 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 22811 53.1543831 -27.8214853 24.337 24.3732 24.2492 23.9758 23.2598 23.5806 22866 53.1547878 -27.7242824 26.6316 26.3694 25.7266 25.5685 24.9763 25.0073 22988 53.1554750 -27.7795274 25.9154 25.9373 25.9879 26.0157 24.226 22.8837 23082 53.1560176 -27.7709408 26.037 25.9845 25.9535 25.8259 24.1002 24.3235 23125 53.1563045 -27.8974074 24.7224 24.602 23.9495 23.6613 22.7736 23.1364 23138 53.1563889 -27.7678324 26.7336 26.7053 26.8996 26.9919 24.2469 24.6767 23292 53.1572595 -27.9234557 26.5692 25.7633 25.556 25.3956 23.4 23.3091 23393 53.1578434 -27.8147559 24.5725 23.9848 23.7245 23.5816 22.5176 22.7051 23542 53.1587342 -27.7574432 25.3823 25.337 24.7664 24.4609 23.6879 24.0986 23552 53.1588013 -27.7050892 25.1687 24.5262 23.7273 23.4197 21.6537 22.0199 23564 53.1588664 -27.7169406 27.3693 26.5784 26.3091 26.4271 24.8405 25.2053 23677 53.1595648 -27.7217102 24.9189 24.8099 24.541 24.0005 22.6373 22.6811 23753 53.1600021 -27.8636693 25.6229 25.4758 24.7683 24.5458 23.302 23.4372 23815 53.1604767 -27.7862937 25.7091 25.5933 24.9448 24.6425 23.9995 24.3813 23970 53.1613194 -27.9152421 25.168 24.4628 24.0034 23.8702 23.7113 23.9199 23998 53.1614942 -27.7676310 25.0135 24.5792 23.9675 23.8487 23.239 23.7265 24024 53.1616106 -27.7469208 25.3531 23.4263 22.025 21.5643 19.5007 19.8852 24050 53.1617434 -27.9313079 26.2439 26.0546 25.792 25.4155 23.6366 23.6018 24133 53.1621880 -27.8054372 24.3802 23.4563 23.059 22.9182 23.0311 23.4701 24155 53.1623473 -27.7844428 26.0363 25.904 25.8899 25.9312 25.1238 25.4914 24167 53.1623895 -27.9063519 26.4183 25.8846 25.7299 25.5292 23.4717 23.3769 24176 53.1624200 -27.8706637 24.6365 24.4999 24.0351 23.4691 21.5739 21.6311 24184 53.1624572 -27.7808475 26.4289 26.4467 26.4509 25.9756 24.5059 24.7293 24199 53.1625195 -27.8165494 26.0361 25.0258 24.7466 24.7974 23.7785 23.8277 24240 53.1627935 -27.6569279 24.7434 23.7936 23.3222 23.1432 23.1183 23.3271 24271 53.1629706 -27.8005117 26.4545 26.3454 26.2656 25.832 24.6195 23.9953 24273 53.1629754 -27.9168787 23.7088 23.7119 23.7627 23.8281 23.387 23.3834 24331 53.1634180 -27.7995476 24.8223 22.5644 21.0988 20.6261 19.1976 19.8214 24332 53.1634219 -27.7766888 25.8381 25.8692 25.9011 25.4527 24.4585 24.8387 24377 53.1636666 -27.6528345 23.3668 21.4519 20.0587 19.5785 19.7511 20.1478 24421 53.1639426 -27.8378714 25.7184 23.6188 22.4933 22.0965 20.9651 21.3848 218 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 24493 53.1644194 -27.8421704 25.1224 22.9378 21.6238 21.1786 19.9106 20.34 24498 53.1644534 -27.7658549 25.6208 25.3233 24.6127 24.2153 23.0643 23.4396 24563 53.1647488 -27.9001864 22.646 22.0347 21.5388 21.4945 21.2181 21.6049 24587 53.1649200 -27.8202369 25.9996 25.829 25.6588 25.3697 23.8181 23.1086 24642 53.1652258 -27.8745277 26.0835 25.6241 24.7601 24.5442 23.7812 24.0265 24647 53.1652522 -27.8511199 26.3302 25.513 25.1241 24.8707 24.7428 25.0669 24747 53.1658838 -27.7815396 24.7647 24.169 23.45 22.9114 21.1813 21.466 24816 53.1663260 -27.7685804 24.2066 23.9666 23.4723 22.8105 21.0216 21.0967 24839 53.1664615 -27.8967688 25.7749 25.6837 25.5907 25.0556 24.0404 24.2333 24919 53.1668882 -27.7986870 24.5365 24.1383 23.7092 23.338 20.8288 20.9516 24933 53.1670009 -27.7846840 25.9286 25.7056 25.4158 25.0887 23.0498 23.0196 25076 53.1679557 -27.9173037 25.7825 25.7311 25.1781 24.6839 23.5076 23.803 25083 53.1680060 -27.8955182 24.9514 24.0836 23.7527 23.6064 23.8612 24.4127 25184 53.1686817 -27.7455783 25.1834 24.2732 23.8682 23.6819 23.6789 24.1005 25225 53.1689598 -27.9258644 25.6507 25.2292 25.269 25.2731 24.5163 24.8921 25236 53.1690556 -27.8037189 26.141 25.6832 25.6428 25.6648 24.4043 24.5652 25360 53.1698429 -27.9181535 23.4618 22.5933 21.5806 21.0512 19.1602 19.4597 25380 53.1699371 -27.7683559 25.8509 25.2224 25.2054 25.3211 24.9641 24.8079 25408 53.1701017 -27.8637822 24.6109 24.5126 24.3308 23.8958 23.2758 23.5499 25465 53.1705219 -27.8066038 24.7576 24.7626 24.5771 24.1092 23.4411 23.6194 25691 53.1720201 -27.6840778 26.2832 25.6884 25.5021 25.3231 22.475 22.3839 25731 53.1722713 -27.7851934 26.8715 26.7914 26.8598 26.8397 25.1963 25.5485 25754 53.1724206 -27.8737467 24.8183 24.0241 23.3348 23.2472 22.9123 23.5008 25795 53.1726273 -27.8214278 24.9549 24.3549 23.6283 23.4075 22.7244 23.2218 25863 53.1729996 -27.8606870 25.1968 24.9858 24.681 24.3971 22.7605 22.7989 25897 53.1732163 -27.8061593 26.5791 26.3713 26.0135 25.8988 23.981 24.0986 26023 53.1740277 -27.7880071 25.2907 24.9828 24.3032 23.7531 22.4568 22.7928 26057 53.1742260 -27.7503394 26.3616 26.1304 25.6362 25.0313 23.7323 24.0335 26075 53.1743685 -27.8816263 24.9458 24.8141 24.2607 23.7752 22.6956 23.0916 26261 53.1756329 -27.8175328 26.5796 25.9723 25.2598 25.1702 24.5982 25.5247 26274 53.1757149 -27.9181423 26.7884 26.222 26.1937 25.9983 23.7904 23.8474 219 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 26320 53.1759928 -27.6919297 25.8595 25.672 25.4282 24.9991 23.3481 23.4789 26322 53.1760006 -27.9145754 24.7105 24.4413 23.7524 23.5888 23.2131 23.698 26324 53.1760124 -27.8362545 24.6725 23.7625 23.1597 23.0196 22.5306 22.8814 26403 53.1766230 -27.6981102 25.603 23.6821 22.3538 21.8631 20.5539 21.0849 26453 53.1770319 -27.7112550 25.6051 25.2791 24.4608 23.7288 20.8084 20.8395 26566 53.1779627 -27.9176939 25.1131 22.6734 21.3522 20.92 19.6904 20.135 26587 53.1781008 -27.7999403 26.3235 26.2847 26.0447 25.7242 24.5507 24.1773 26588 53.1781073 -27.8680779 24.071 23.559 22.9158 22.7733 22.3385 22.7904 26646 53.1784173 -27.8065481 26.5138 26.386 26.3838 26.4743 24.5538 24.5107 26653 53.1784610 -27.7665444 25.6796 25.0528 24.2875 24.17 23.5737 24.1493 26723 53.1789625 -27.6958450 26.4814 25.2549 24.9598 24.9478 24.7345 24.6746 26731 53.1790175 -27.7011329 24.4572 24.1165 23.5994 23.1715 21.5107 21.5862 26775 53.1793252 -27.8920237 25.1997 24.6009 23.7708 23.5919 22.9735 23.4764 26782 53.1793508 -27.8973915 25.3564 24.5828 24.4051 24.4212 23.3032 23.9845 26792 53.1794441 -27.7857469 26.6548 26.1484 26.1678 26.3112 25.3473 25.0502 26842 53.1797610 -27.7656593 26.0966 26.0915 26.0644 25.898 24.9496 25.214 26856 53.1798723 -27.8882188 24.788 24.2575 23.7712 23.8272 23.6453 24.0751 26857 53.1798922 -27.9207284 25.5855 25.0618 24.5989 24.2412 20.4221 20.1644 26868 53.1800140 -27.8653862 26.7433 26.5383 26.2132 25.8125 24.8734 24.4667 26904 53.1802510 -27.7423952 26.5847 26.5021 26.2796 25.7121 24.2283 24.4398 26906 53.1802571 -27.7523896 25.8803 25.1024 24.5836 24.5037 24.0235 24.3524 26941 53.1806052 -27.7048718 26.5584 26.4281 25.854 25.3888 23.892 24.5311 26993 53.1809281 -27.7222162 25.1521 24.9742 24.5973 24.4131 23.785 24.3668 27042 53.1812516 -27.7274391 26.9604 26.6643 26.6091 26.67 24.6737 24.6389 27190 53.1823947 -27.8856560 26.3089 25.7611 25.7247 25.7783 24.5814 24.519 27221 53.1826622 -27.6988455 26.005 25.4564 25.1738 25.0167 23.0219 23.0257 27228 53.1827174 -27.8898145 25.368 25.327 25.1021 24.7546 23.7316 23.9716 27234 53.1827927 -27.7052808 24.5689 24.5414 24.5981 24.6811 24.1782 24.0751 27253 53.1830180 -27.7005601 25.3908 22.9715 21.4974 20.987 19.4139 19.9635 27262 53.1830767 -27.9103023 25.5163 25.3333 25.0766 25.0056 22.8503 22.7596 27285 53.1832374 -27.8810238 26.6669 26.536 26.4036 26.3204 25.1262 25.0669 220 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 27319 53.1835582 -27.8620224 21.1635 19.6388 18.8507 18.4908 17.5656 17.6607 27339 53.1837530 -27.8702571 22.9955 21.6535 21.0753 20.8761 21.5399 22.0575 27357 53.1838960 -27.7482060 25.1542 23.9794 23.1907 22.9216 22.095 22.4289 27388 53.1841604 -27.7797425 25.8705 25.1801 24.5882 24.5157 24.0506 24.5236 27448 53.1845745 -27.7833258 25.9183 25.7119 25.3059 25.0932 24.1876 24.8968 27473 53.1847720 -27.7774443 24.5899 23.8704 23.3524 23.1785 22.8909 23.2777 27474 53.1847725 -27.9184468 25.257 25.153 24.9391 24.341 23.3738 23.5315 27483 53.1848786 -27.9257898 24.711 24.2041 23.4806 23.3178 22.6018 22.6773 27584 53.1857186 -27.7722201 25.7218 23.9869 23.2211 22.9836 23.5899 24.0781 27604 53.1858313 -27.8099672 25.6723 25.1998 24.762 24.698 21.9276 21.6766 27615 53.1858997 -27.8803917 24.3978 23.7599 23.0907 22.9711 22.5068 22.8894 27641 53.1860963 -27.9057857 26.6766 26.5497 26.4064 26.0383 24.4564 24.8475 27642 53.1861020 -27.8078911 26.186 25.884 25.4562 24.8445 23.3037 23.4352 27687 53.1864994 -27.8976000 25.8734 25.8522 25.7735 25.8096 24.8977 24.7136 27745 53.1869709 -27.8690629 25.257 24.7406 24.0106 23.7818 23.3579 23.9533 27803 53.1874076 -27.8122479 24.1861 23.9891 23.7685 23.632 22.0766 22.0311 27852 53.1878153 -27.7726224 23.6835 23.0254 22.6654 22.6203 22.9964 23.365 27949 53.1884712 -27.8796819 25.524 25.2745 25.1605 25.0094 23.4914 23.4291 28041 53.1891436 -27.8351489 26.1892 25.8308 25.548 25.2248 22.8269 22.7274 28092 53.1896102 -27.8383932 24.9228 24.4021 23.6264 23.1328 21.8028 22.1084 28299 53.1914669 -27.7738871 25.0274 24.1607 23.772 23.6158 23.7236 24.2333 28309 53.1915646 -27.7826686 24.2801 23.9708 23.6738 23.0617 21.612 21.7108 28366 53.1920694 -27.8424031 27.4497 27.2196 27.165 27.0684 25.0148 24.9454 28464 53.1928075 -27.9166991 24.9733 24.6799 24.3797 23.97 22.6707 22.6975 28531 53.1933584 -27.9161343 24.4623 24.4873 24.525 24.2929 24.1319 23.9517 28565 53.1936764 -27.8577876 25.7581 25.4899 25.1154 24.5343 23.1264 23.3663 28568 53.1936906 -27.7908932 25.825 24.9646 24.376 24.2393 23.956 24.3684 28591 53.1938675 -27.7932945 24.7585 23.9923 23.2475 23.0609 22.1703 22.6067 28636 53.1942813 -27.8157583 26.2419 26.102 26.0087 25.8226 24.3437 24.3181 28644 53.1943366 -27.8591250 26.2703 25.9845 25.6222 24.9244 23.6869 24.1929 28771 53.1954272 -27.8018188 27.0196 27.0023 26.9034 26.9008 25.1105 25.4944 221 Table C.1 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 28784 53.1955186 -27.7680048 26.1037 25.147 24.8422 24.785 23.1554 23.0376 28808 53.1957370 -27.8071874 25.0147 24.1964 23.7436 23.585 23.4798 23.7692 28841 53.1959426 -27.7312771 26.4245 26.3192 25.7884 25.7429 24.4465 24.9305 28931 53.1966873 -27.8934731 24.6264 24.4416 24.3338 24.2362 22.75 22.7618 28954 53.1968441 -27.8098270 27.6961 27.2717 27.0312 26.9887 24.7737 24.5566 28959 53.1968593 -27.8610285 26.7918 25.9231 25.6297 25.7318 24.6573 24.775 28997 53.1971565 -27.8382556 26.7986 26.68 25.8427 25.5662 24.5553 25.35 29071 53.1978415 -27.9016391 25.1645 24.5707 24.0488 23.9555 23.929 24.4261 29092 53.1980325 -27.8666422 21.7893 21.2713 21.0272 20.9964 22.2262 22.7429 29101 53.1981243 -27.9062649 26.7292 26.1986 25.7771 25.8694 24.0729 24.2811 29275 53.1995637 -27.8632190 24.1937 24.3234 24.2941 24.0955 23.7301 24.0271 222 Table C.2. B-dropout Lyman-break Sample ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 506 53.0012892 -27.7140714 ··· 24.1618 23.4886 23.4185 23.2714 23.8539 771 53.0076812 -27.7018293 ··· 25.4839 25.3276 25.3829 23.2731 23.0083 1038 53.0119708 -27.7300404 ··· 25.9263 25.4945 25.4269 24.8145 24.3406 1164 53.0138774 -27.7376281 ··· 26.6386 26.09 26.1819 24.9468 24.6338 1168 53.0139426 -27.7418060 ··· 26.6108 26.0932 26.0383 24.982 24.8154 1214 53.0147716 -27.7517432 ··· 26.1692 25.5803 25.4684 24.7162 24.4219 1289 53.0157411 -27.7650875 ··· 25.8522 25.4354 25.3396 24.571 24.641 1340 53.0166033 -27.7448462 ··· 26.577 25.559 25.4958 22.7419 22.675 1360 53.0168869 -27.7229871 ··· 27.0578 26.1673 25.9265 24.3815 24.6389 1623 53.0205796 -27.7421451 ··· 23.9149 23.7182 23.6935 22.5354 22.393 1649 53.0209287 -27.7701811 ··· 25.2615 24.6195 24.57 23.5705 24.1119 1972 53.0244761 -27.6947526 ··· 26.5862 25.9695 25.7799 24.1815 24.641 2488 53.0302265 -27.7300466 ··· 26.7239 26.1863 26.114 25.3252 25.0963 2556 53.0307926 -27.7348899 ··· 25.7863 25.563 25.6137 25.0486 24.9198 2601 53.0312202 -27.7852309 ··· 25.7908 25.1208 25.0966 23.4027 23.2435 2717 53.0322537 -27.7310381 ··· 26.2416 25.7798 25.7507 24.7493 25.0885 3125 53.0359793 -27.7700350 ··· 26.7882 26.419 26.3145 25.7197 25.3304 3517 53.0395599 -27.8285109 ··· 26.4973 26.116 26.0568 25.6642 25.4561 3542 53.0398889 -27.7984708 ··· 26.851 26.5897 26.5397 24.3016 24.2171 3592 53.0401469 -27.8038500 ··· 26.8242 25.9702 26.0286 24.8304 24.9812 3659 53.0406907 -27.7181709 ··· 25.8952 25.6297 25.6259 23.0555 23.0533 3709 53.0410891 -27.7561579 ··· 26.8631 26.077 26.1631 24.5734 24.2613 3746 53.0413958 -27.6957415 ··· 25.8023 25.2885 25.3279 24.9435 25.1881 3748 53.0414173 -27.8045746 ··· 25.6488 25.2652 25.3299 24.9853 25.0514 3847 53.0423060 -27.7814212 ··· 26.1879 25.8992 25.9046 25.071 24.9648 3909 53.0428596 -27.7935259 ··· 27.363 26.1861 26.1631 24.5277 24.5376 4088 53.0443548 -27.8414304 ··· 27.0006 25.846 25.8229 24.7605 25.2498 4111 53.0444797 -27.7725276 ··· 26.3521 26.0174 26.0273 22.7409 22.4502 4210 53.0453172 -27.6984456 ··· 26.4719 25.8338 25.8001 24.3936 24.1473 4225 53.0454326 -27.7737949 ··· 26.8671 26.201 26.2099 23.4984 23.7902 4404 53.0468126 -27.7033002 ··· 26.0345 25.5742 25.5996 24.9073 24.9224 223 Table C.2 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 4449 53.0470991 -27.7170366 ··· 27.4171 26.5182 26.4598 24.1965 24.2938 4451 53.0471123 -27.8169164 ··· 27.4232 26.8163 26.7202 24.4896 24.1699 4637 53.0484035 -27.7972102 ··· 27.2401 26.5801 26.4031 24.7567 25.0655 4642 53.0484391 -27.7724251 ··· 26.455 26.2912 26.3931 24.7549 24.5236 5161 53.0520491 -27.7616999 ··· 26.3636 25.7588 25.7249 24.9615 25.1396 5330 53.0532829 -27.8007245 ··· 27.3984 26.0726 26.0367 24.3743 24.7747 5335 53.0533066 -27.8018702 ··· 27.407 26.8729 26.5186 26.2067 25.5346 5417 53.0540032 -27.7353427 ··· 26.7103 26.1331 26.1849 24.5036 24.7147 5427 53.0540957 -27.8114070 ··· 25.8069 25.1214 25.0856 24.3625 24.4773 5429 53.0541079 -27.8093730 ··· 26.8991 25.7447 25.6346 24.1915 24.3969 5534 53.0548184 -27.7781618 ··· 26.4498 25.9766 25.8983 22.8271 22.9482 5568 53.0550669 -27.7784980 ··· 25.9301 25.6053 25.6441 25.0304 24.7015 5639 53.0556353 -27.8176661 ··· 26.5768 25.9739 25.9006 23.8865 23.6597 5944 53.0580796 -27.7409968 ··· 27.4107 26.2469 26.1012 24.0027 23.971 5993 53.0583862 -27.6953527 ··· 25.7606 25.3582 25.2897 24.2197 24.2826 5996 53.0584111 -27.8750301 ··· 27.5543 26.9539 26.8821 24.8365 24.6094 6085 53.0589771 -27.8442096 ··· 26.9416 26.5277 26.4229 25.101 25.2915 6211 53.0599101 -27.8447086 ··· 27.0976 26.3063 26.3192 25.0477 24.992 6245 53.0600960 -27.7295884 ··· 26.4943 26.1336 26.1756 25.4159 24.9454 6294 53.0604039 -27.8257471 ··· 26.8013 25.8068 25.8133 25.1292 25.498 6344 53.0607606 -27.8064526 ··· 27.1874 26.5536 26.7281 25.328 25.4411 6382 53.0610467 -27.8600422 ··· 27.5309 26.748 26.6064 25.1844 25.2605 6393 53.0611204 -27.8758259 ··· 26.3607 25.5959 25.5544 23.2097 23.0721 6404 53.0612026 -27.7744756 ··· 26.474 25.9493 25.9009 24.8086 24.5594 6830 53.0640577 -27.8051667 ··· 25.9723 25.4869 25.4214 24.9063 24.8128 6950 53.0648261 -27.7265220 ··· 26.0714 25.5661 25.4659 24.5051 24.1612 7007 53.0651924 -27.7250957 ··· 27.0349 26.662 26.5506 25.0006 24.9551 7063 53.0656183 -27.6995433 ··· 26.8339 26.4624 26.3553 25.7152 25.237 7083 53.0657271 -27.6871892 ··· 26.9398 26.5184 26.3627 24.6573 24.7553 7266 53.0669563 -27.7405703 ··· 26.2642 25.6669 25.7227 24.6245 24.7473 7362 53.0676377 -27.8122626 ··· 27.352 26.0607 26.1154 23.9686 23.8539 224 Table C.2 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 7366 53.0676945 -27.8454207 ··· 27.3453 26.8889 26.908 25.771 25.5085 7392 53.0678804 -27.8745087 ··· 27.3604 26.5292 26.3074 24.2323 23.9109 7591 53.0693249 -27.7148192 ··· 25.3829 24.9482 24.9581 24.5999 24.4989 7701 53.0700709 -27.8415646 ··· 26.1821 25.5711 25.3922 25.4832 23.2872 7721 53.0702342 -27.8455319 ··· 26.0488 25.4907 25.2365 22.8541 22.4816 7791 53.0706297 -27.8356332 ··· 26.5398 26.1986 26.2933 24.1515 23.8434 7890 53.0712010 -27.8675699 ··· 26.4519 26.137 25.963 24.45 24.5052 7917 53.0713916 -27.7049474 ··· 25.5165 25.2838 25.2991 25.1529 24.768 7989 53.0717322 -27.7984386 ··· 25.1893 24.8842 24.9051 24.5663 24.2886 8168 53.0727740 -27.8306020 ··· 26.423 25.9415 25.9833 24.6421 24.8137 8200 53.0729668 -27.6994880 ··· 26.3464 25.8773 25.9936 23.7356 23.4621 8269 53.0733626 -27.8874660 ··· 26.1158 25.7977 25.7089 24.8234 24.8154 8323 53.0735918 -27.8922303 ··· 24.9291 24.4466 24.3596 23.0132 22.8719 8364 53.0738507 -27.7181465 ··· 27.2817 26.6651 26.4026 25.1844 24.9305 8373 53.0738963 -27.8852256 ··· 25.784 25.4309 25.4567 25.0861 24.9292 8536 53.0748911 -27.7534760 ··· 27.0595 26.1698 25.9917 23.4515 23.167 8575 53.0752105 -27.7552784 ··· 25.6714 25.0549 24.9606 23.5524 23.3194 8715 53.0760689 -27.8007021 ··· 25.9097 24.925 24.8058 24.0013 24.5817 8741 53.0761834 -27.8663637 ··· 25.1151 24.5061 24.3021 23.0144 22.8697 8889 53.0770895 -27.7513444 ··· 27.5779 26.6631 26.5355 24.3022 24.2227 8893 53.0771143 -27.7347092 ··· 27.3269 27.2018 27.07 25.5651 25.3461 8974 53.0777424 -27.6967276 ··· 25.7795 25.2636 25.1893 24.5702 24.5007 9104 53.0784531 -27.8731624 ··· 26.1628 25.4916 25.3836 22.6977 22.5175 9106 53.0784674 -27.8598579 ··· 26.1119 25.6384 25.4642 21.6727 21.4093 9131 53.0785983 -27.6967052 ··· 27.0845 26.3761 26.154 24.2146 24.2276 9237 53.0792861 -27.8772644 ··· 25.9366 24.6676 24.5393 23.3308 23.5138 9258 53.0794221 -27.7175642 ··· 27.3515 26.728 26.6326 24.6064 24.5508 9275 53.0795435 -27.6970039 ··· 26.239 25.4553 25.1869 23.2719 23.2291 9349 53.0799702 -27.8556652 ··· 26.3128 26.1176 26.226 25.3411 25.2679 9440 53.0805899 -27.7208170 ··· 27.1695 26.6512 26.233 22.6451 22.4077 9543 53.0812347 -27.8746003 ··· 26.2775 25.7375 25.7118 24.1099 24.001 225 Table C.2 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 9618 53.0816804 -27.8111118 ··· 25.8784 25.505 25.4889 25.4307 25.4715 9698 53.0821487 -27.8378219 ··· 26.7301 26.1319 26.0654 24.8125 24.3668 9762 53.0825519 -27.8835715 ··· 25.1724 24.6991 24.6052 23.7694 23.6271 9895 53.0835106 -27.8818634 ··· 26.9061 26.634 26.7232 24.9694 24.8525 9972 53.0840188 -27.8234535 ··· 25.8796 25.5969 25.517 24.6833 24.4501 10165 53.0852949 -27.6964257 ··· 27.1829 26.8712 26.9864 24.8204 25.1644 10327 53.0862494 -27.9267091 ··· 26.8347 25.8158 25.8096 24.7605 24.4312 10469 53.0872303 -27.7295271 ··· 25.04 24.6641 24.669 24.2973 24.1447 10555 53.0877079 -27.8056858 ··· 25.8284 25.6518 25.9116 25.0419 24.8076 10619 53.0880708 -27.8820767 ··· 25.9831 25.4794 25.494 25.1079 24.9958 10649 53.0882919 -27.6751212 ··· 27.3781 26.6367 26.5381 22.8061 22.6714 10739 53.0888447 -27.9489146 ··· 24.9087 24.5501 24.614 23.7985 23.8962 10778 53.0891095 -27.7105762 ··· 26.7531 26.136 26.1493 25.0124 25.0715 11099 53.0909013 -27.6901129 ··· 25.77 25.269 25.2211 24.4479 24.406 11287 53.0918915 -27.6761308 ··· 26.2245 25.7916 25.8383 24.8145 24.8702 11647 53.0941388 -27.8550091 ··· 25.7146 25.2522 25.2188 23.8232 23.8088 11767 53.0948007 -27.7857861 ··· 27.1596 26.1446 26.1331 24.6395 24.9147 11779 53.0948780 -27.7703875 ··· 26.093 25.6148 25.6091 24.9948 24.8094 11833 53.0951812 -27.7438469 ··· 25.2992 25.067 25.0686 23.8404 23.6058 12152 53.0972367 -27.8657967 ··· 24.184 23.4995 23.4089 21.8889 21.6665 12274 53.0980585 -27.7989094 ··· 27.0135 26.3623 26.3881 24.9366 25.0595 12533 53.0995912 -27.8021789 ··· 26.6983 25.7678 25.7732 25.068 25.7336 12774 53.1009203 -27.8275100 ··· 26.7658 26.3789 26.4474 25.2526 25.2102 12778 53.1009453 -27.6915218 ··· 26.1765 25.2032 25.0954 23.3701 24.5125 12975 53.1020453 -27.8707117 ··· 26.0134 25.5078 25.6062 24.2323 24.1793 13177 53.1031448 -27.8083460 ··· 27.2088 26.6512 26.6847 25.1278 25.2558 13544 53.1051975 -27.7663362 ··· 27.0666 26.4338 26.6287 25.0401 25.0059 13586 53.1054047 -27.7398731 ··· 27.5877 27.0038 26.7575 24.8096 24.4389 13770 53.1064311 -27.7334863 ··· 25.77 25.2807 25.292 24.2664 24.6074 13803 53.1065985 -27.8528046 ··· 27.0575 26.397 26.2826 24.4686 24.5433 13871 53.1069967 -27.7928889 ··· 26.183 25.9236 25.9244 24.8436 24.8821 226 Table C.2 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 13949 53.1074174 -27.8693093 ··· 25.714 25.2621 25.1568 23.3086 23.3012 13986 53.1076011 -27.7139781 ··· 25.959 25.2838 25.2371 24.0174 24.244 14006 53.1076904 -27.8569629 ··· 27.2091 26.4504 26.5345 25.6239 25.1847 14113 53.1082772 -27.7986549 ··· 26.8796 25.9345 25.7827 23.648 23.8145 14285 53.1091005 -27.8698047 ··· 25.313 24.6597 24.6273 23.7511 23.6838 14374 53.1094515 -27.7440561 ··· 26.743 26.4042 26.1664 25.2211 25.2939 14391 53.1094949 -27.8793594 ··· 25.2992 24.9283 24.977 24.2628 24.0472 14406 53.1095619 -27.8692351 ··· 26.9858 26.1322 25.997 24.7756 24.6671 14555 53.1103747 -27.6899919 ··· 25.8833 25.3457 25.2511 24.0155 23.8569 14772 53.1115039 -27.8738644 ··· 24.749 24.2405 24.2349 23.3364 23.2342 14800 53.1116327 -27.8607736 ··· 26.1429 25.5011 25.3902 24.4779 24.1779 14817 53.1116991 -27.8766974 ··· 26.9344 26.4367 26.4266 24.8436 25.0263 14880 53.1119471 -27.8711622 ··· 27.0599 25.9121 25.8326 23.6306 23.3938 15403 53.1145845 -27.8052111 ··· 26.7421 26.3812 26.4355 24.5201 24.5566 15517 53.1151486 -27.8499118 ··· 26.0267 25.3334 25.2694 23.7596 23.9677 15696 53.1161257 -27.8889095 ··· 27.3611 26.4045 26.394 24.8589 25.3905 15713 53.1161770 -27.7822014 ··· 27.3012 26.6803 26.6209 25.6537 25.4172 15839 53.1168295 -27.8565011 ··· 26.0892 25.7801 25.8852 25.6386 25.1169 15920 53.1174699 -27.7203930 ··· 26.8847 26.4986 26.2575 25.071 25.1711 15960 53.1177095 -27.6867688 ··· 24.9314 24.5375 24.5692 24.3743 24.2276 15997 53.1179148 -27.7343242 ··· 25.2438 24.7939 24.6035 21.4686 21.2431 16222 53.1189748 -27.8936592 ··· 27.1183 26.7564 26.7165 25.6428 25.2958 16449 53.1200370 -27.6867180 ··· 26.7608 26.1424 25.831 23.9897 23.9199 16613 53.1209201 -27.7094327 ··· 25.4732 25.0876 25.2334 24.693 24.5817 16616 53.1209328 -27.8842767 ··· 27.2247 26.9369 26.7412 24.996 24.8313 16703 53.1214169 -27.8146166 ··· 25.1492 24.7324 24.785 24.1683 23.9873 16931 53.1226685 -27.8903671 ··· 26.9289 26.5321 26.5156 23.8538 23.6702 17250 53.1243736 -27.8516316 ··· 25.2752 24.695 24.7338 21.8297 22.0423 17468 53.1254117 -27.8493687 ··· 26.0998 25.7363 25.643 23.5417 24.1119 17508 53.1256247 -27.8493049 ··· 26.0766 25.5948 25.5832 24.0749 24.6671 18009 53.1282912 -27.8456813 ··· 26.5491 26.0216 26.0564 24.5484 24.6874 227 Table C.2 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 18188 53.1291404 -27.8010818 ··· 27.5732 26.9416 26.9008 25.1628 25.2677 18294 53.1297725 -27.8566500 ··· 26.4655 25.891 25.6507 24.0496 23.9688 18327 53.1299505 -27.9081561 ··· 27.411 26.6687 26.1887 22.2728 22.2102 18467 53.1306010 -27.7510262 ··· 27.0161 26.7084 26.8596 25.4742 25.0715 18523 53.1309157 -27.8634076 ··· 26.6845 26.4888 26.4173 25.1569 25.0278 18602 53.1313182 -27.7929505 ··· 26.5541 26.1309 26.0806 25.1234 24.8989 18666 53.1317012 -27.7374379 ··· 26.0781 25.7389 25.7284 25.1542 25.1445 18729 53.1320449 -27.7528047 ··· 26.3939 25.5773 25.5836 24.4003 24.5585 18948 53.1332585 -27.9029261 ··· 26.3909 25.335 25.2147 20.9789 20.8404 19015 53.1336817 -27.6934506 ··· 25.4955 24.9244 24.9056 24.1478 23.9907 19119 53.1342949 -27.7050574 ··· 26.1756 25.9984 25.9046 23.6723 24.0079 19126 53.1343195 -27.6943113 ··· 27.4567 26.8706 26.743 24.9009 24.7691 19129 53.1343376 -27.9079528 ··· 27.2921 26.9301 26.8786 24.9843 25.019 19632 53.1371354 -27.8736829 ··· 26.3323 25.9964 25.9497 25.4039 25.4389 19640 53.1371812 -27.9158423 ··· 27.0388 26.3574 26.2789 22.7989 22.6524 19702 53.1376084 -27.8675430 ··· 25.6498 25.294 25.2608 23.8836 23.5492 19739 53.1377918 -27.7955409 ··· 26.6066 26.0141 25.9728 23.8324 23.6647 19866 53.1385014 -27.8211264 ··· 25.975 25.4158 25.4101 23.8802 23.601 20238 53.1406010 -27.8269001 ··· 26.8475 26.2357 26.0816 24.1361 24.2171 20256 53.1406939 -27.8732570 ··· 26.7293 25.8045 25.672 22.64 22.4109 20513 53.1420025 -27.7974094 ··· 26.9149 26.2121 26.3623 25.2346 25.4027 20638 53.1426232 -27.8265447 ··· 25.3311 25.1689 25.3164 24.1532 23.6997 20721 53.1430508 -27.8761935 ··· 26.3801 25.846 25.7778 24.0496 23.9879 20730 53.1431208 -27.8155038 ··· 25.3329 24.4546 24.2851 23.071 23.2299 20840 53.1437820 -27.7321149 ··· 26.1096 26.0681 26.0823 25.0511 24.94 20954 53.1443858 -27.6875980 ··· 25.6433 25.0017 24.9124 23.7615 23.6685 21073 53.1451273 -27.8903380 ··· 25.1442 24.567 24.4958 22.6761 22.4237 21203 53.1456988 -27.6698984 ··· 26.6209 26.2081 26.2789 24.7949 24.64 21226 53.1458752 -27.6881955 ··· 26.8412 26.084 26.0495 24.7465 24.5395 21273 53.1460876 -27.8762721 ··· 25.7739 25.2729 25.3182 23.6723 23.5986 21677 53.1482659 -27.7802574 ··· 27.2708 26.8128 26.861 25.6382 25.2973 228 Table C.2 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 21727 53.1484969 -27.7772846 ··· 26.1532 25.547 25.304 24.4543 24.1936 21811 53.1489661 -27.8025095 ··· 26.9942 26.2217 26.1342 24.6353 24.2701 21960 53.1498240 -27.6972158 ··· 24.5672 24.2133 24.1554 23.7433 23.5175 22005 53.1500852 -27.8196368 ··· 27.0714 26.713 26.699 25.5492 25.6075 22101 53.1507393 -27.8208233 ··· 27.0941 25.9952 25.8694 24.4529 24.986 22169 53.1511113 -27.6955952 ··· 27.1116 26.6365 26.6086 24.4657 24.508 22205 53.1512654 -27.8733088 ··· 26.5482 26.0442 26.0276 24.8446 24.9523 22441 53.1522817 -27.9389034 ··· 26.9653 26.4735 26.4262 23.8328 23.5644 22641 53.1534713 -27.8213967 ··· 26.7589 26.05 26.0994 25.4959 25.1166 22642 53.1534909 -27.6887222 ··· 26.725 26.2346 25.9407 23.8288 24.0183 22808 53.1543737 -27.7395083 ··· 27.1451 26.837 26.7709 25.6177 25.1847 22878 53.1548581 -27.7063473 ··· 26.4645 25.8633 26.039 24.7502 24.801 23084 53.1560258 -27.7303251 ··· 27.0142 26.0176 25.8747 23.9962 24.0905 23637 53.1593319 -27.8772007 ··· 26.9432 26.017 25.9145 23.5976 23.4403 23722 53.1598097 -27.8923887 ··· 26.4149 25.6423 25.7419 23.4395 23.2359 23851 53.1606907 -27.8191893 ··· 26.2802 25.8507 25.9006 25.8178 25.4389 23916 53.1610099 -27.8799487 ··· 26.796 26.1831 26.141 23.8575 23.8049 23943 53.1611265 -27.8863102 ··· 26.782 26.2865 26.1551 23.7492 23.7794 23958 53.1612496 -27.8763296 ··· 27.1794 26.4504 26.3518 23.8954 23.6522 23979 53.1613709 -27.7370371 ··· 26.4189 25.6276 25.4282 23.325 23.4541 24038 53.1616799 -27.9187386 ··· 27.1112 26.3697 26.131 22.3589 22.2683 24279 53.1630047 -27.7976545 ··· 27.107 26.4817 25.6657 22.0163 22.0255 24439 53.1640413 -27.7201410 ··· 27.4128 26.5321 26.5543 25.0635 25.2808 24465 53.1642034 -27.7729285 ··· 26.7421 26.4571 26.2057 24.3638 24.4093 24500 53.1644566 -27.9068547 ··· 26.6347 26.2598 26.0675 25.061 24.9251 24650 53.1652745 -27.8140613 ··· 25.8498 24.9323 24.723 21.0141 20.8606 24804 53.1662376 -27.8198229 ··· 27.0546 26.6755 26.6948 24.1245 23.9682 24940 53.1670264 -27.8170020 ··· 27.1701 26.9121 26.9927 25.8717 25.5983 25010 53.1675434 -27.9077053 ··· 26.9837 26.281 26.2512 24.9095 24.9973 25059 53.1678725 -27.6742245 ··· 26.8215 26.3348 25.9434 23.3966 22.8729 25118 53.1682704 -27.7419449 ··· 25.854 25.3399 25.3489 24.4621 25.1728 229 Table C.2 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 25237 53.1690558 -27.9158878 ··· 26.6922 26.0617 25.1181 20.7388 20.5854 25614 53.1714968 -27.8504161 ··· 26.4129 25.6158 25.5573 24.3159 24.5749 25809 53.1727140 -27.7932631 ··· 27.0128 26.9619 26.9397 25.4566 25.7527 26034 53.1741119 -27.7729651 ··· 27.2279 26.6845 26.8214 25.1824 25.0938 26190 53.1752274 -27.7945985 ··· 26.3379 25.9405 25.915 23.5956 23.666 26256 53.1755955 -27.7687476 ··· 26.7268 26.247 26.2381 24.371 24.3445 26308 53.1758950 -27.7615534 ··· 26.2784 25.4926 25.3027 23.2012 23.0507 26456 53.1770676 -27.7643529 ··· 24.7445 24.447 24.4533 24.1022 23.8078 26507 53.1774842 -27.7490115 ··· 26.5192 26.0615 26.1697 25.1014 25.368 26656 53.1784899 -27.7840362 ··· 24.9588 24.9586 24.9471 23.1841 23.1123 26744 53.1790943 -27.8407428 ··· 27.1566 27.114 27.1434 25.1014 25.4008 26880 53.1801287 -27.7259055 ··· 27.2804 26.0459 26.027 24.6514 24.9802 26954 53.1806741 -27.8449086 ··· 26.786 26.1034 26.1823 25.0647 25.2406 27122 53.1818664 -27.9066391 ··· 25.4506 24.9697 24.9129 24.2676 24.2819 27248 53.1829444 -27.8804622 ··· 26.8388 25.775 25.485 23.674 23.7766 27277 53.1831962 -27.9017602 ··· 26.8074 26.5408 26.7074 25.1079 25.1745 27344 53.1837813 -27.9145986 ··· 25.3825 25.0261 25.0415 22.9227 22.8674 27370 53.1839721 -27.8436897 ··· 26.9588 26.592 26.7306 25.1678 25.2496 27462 53.1846713 -27.7386936 ··· 27.2808 26.5411 26.5927 24.6677 24.4211 27572 53.1856661 -27.7732206 ··· 26.7838 26.288 26.082 25.3075 25.1251 27622 53.1859646 -27.9219287 ··· 26.3137 26.0004 25.825 22.931 22.8132 27895 53.1880836 -27.8411358 ··· 26.2829 26.1453 26.0103 24.5608 24.6535 27931 53.1883446 -27.9058483 ··· 26.1953 25.6945 25.6696 23.1539 23.0306 28022 53.1890444 -27.8928016 ··· 26.8435 26.4091 26.4488 25.0925 24.8689 28120 53.1898794 -27.8925963 ··· 25.4267 24.8527 24.7566 23.9551 23.6497 28130 53.1899717 -27.7702960 ··· 27.4488 26.9521 26.7728 25.7734 25.5753 28377 53.1921280 -27.7409289 ··· 27.6027 26.7739 26.4337 23.1445 22.9764 28396 53.1923028 -27.8968011 ··· 26.5763 26.0642 26.176 24.7643 24.8689 28451 53.1926968 -27.8130525 ··· 25.7523 24.9697 24.9579 23.8878 23.9867 28556 53.1935948 -27.8152386 ··· 27.2105 26.3929 26.2982 25.2616 25.2593 28638 53.1942919 -27.8953662 ··· 26.424 25.9975 26.0578 24.9705 24.8425 230 Table C.2 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 28708 53.1949641 -27.7870439 ··· 27.3197 26.516 26.6349 24.8096 24.5895 28839 53.1959284 -27.7726881 ··· 26.9391 26.5923 26.5622 24.3329 24.2916 29022 53.1974288 -27.7905858 ··· 27.0632 26.1246 25.9703 24.1282 24.2269 29178 53.1987362 -27.7788827 ··· 26.8155 25.6063 25.5362 24.4057 24.5768 29298 53.1997930 -27.8849342 ··· 26.3045 25.2537 25.225 24.1629 24.2953 29312 53.1999732 -27.9168683 ··· 27.5363 26.6936 26.6735 25.5397 25.2846 29399 53.2006942 -27.7727306 ··· 26.5115 26.1072 26.0888 24.4955 24.497 29411 53.2008080 -27.8972598 ··· 26.384 25.8586 25.9416 25.1183 24.9676 29436 53.2010159 -27.8602499 ··· 26.1066 25.1101 24.9731 24.3373 25.0979 29483 53.2015184 -27.9185288 ··· 26.6249 25.8212 25.7092 24.7345 24.896 29510 53.2017836 -27.9178676 ··· 26.4783 25.6158 25.4844 24.4736 24.5876 29512 53.2017959 -27.9087751 ··· 27.0214 26.6243 26.3967 24.7162 24.6155 29605 53.2026046 -27.8156255 ··· 25.9899 25.5107 25.5166 24.4493 24.6236 30313 53.2093570 -27.8810938 ··· 26.2019 25.9089 25.898 23.0015 22.431 30744 53.2134329 -27.8680754 ··· 26.8193 26.2708 26.176 25.6642 25.4113 31228 53.2184145 -27.9175123 ··· 26.7909 26.447 26.5857 23.5073 23.1146 31272 53.2189137 -27.8042621 ··· 25.5667 25.1753 25.097 23.9746 23.8126 31478 53.2208654 -27.8649315 ··· 26.1005 24.8221 24.8027 23.8236 23.9621 31480 53.2208737 -27.8334861 ··· 25.3277 24.4369 24.3736 23.5283 23.7789 32366 53.2302041 -27.8395714 ··· 25.4614 24.6422 24.5675 23.5444 23.7655 32634 53.2342683 -27.8992612 ··· 26.4139 25.795 25.5594 21.9423 21.6441 32900 53.2382032 -27.8625039 ··· 26.2572 24.739 24.7037 24.2191 24.6297 32979 53.2396377 -27.8638823 ··· 25.971 25.1522 25.0764 24.2893 24.7081 33367 53.2471541 -27.8859240 ··· 26.7507 26.1724 26.1235 25.1637 24.962 33532 53.2516339 -27.9048386 ··· 26.5608 26.1534 26.2218 24.8871 24.7832 33547 53.2519882 -27.9019902 ··· 26.1936 25.6618 25.7999 24.4977 24.3067 33648 53.2551112 -27.9043989 ··· 25.7082 25.2932 25.0792 23.7283 23.6889 231 Table C.3. V-dropout Lyman-break Sample RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 753 53.0073861 -27.7336334 ··· ··· 26.341 25.5233 21.2067 21.2445 1669 53.0211687 -27.7823650 ··· ··· 24.0778 23.868 22.4351 22.5517 1707 53.0214958 -27.7872834 ··· ··· 26.4752 26.3949 24.0089 24.1559 1732 53.0217586 -27.7874730 ··· ··· 26.8013 26.4555 23.2374 23.6954 1745 53.0219103 -27.7167829 ··· ··· 25.3391 25.3734 24.4918 24.8264 4532 53.0476899 -27.7940642 ··· ··· 26.1458 25.9395 23.9382 24.0312 4685 53.0488086 -27.6971100 ··· ··· 25.6621 25.4072 24.7409 25.2001 ID 6820 53.0639978 -27.8266912 ··· ··· 26.5785 26.6377 25.765 25.7115 7544 53.0689918 -27.8071872 ··· ··· 26.9652 26.8207 23.059 23.2165 7632 53.0696162 -27.7233673 ··· ··· 20.5824 19.7377 19.4852 19.9056 8585 53.0752957 -27.8127068 ··· ··· 23.9036 23.1773 23.1348 23.6202 8882 53.0770413 -27.7059261 ··· ··· 24.2072 23.1398 22.7305 23.2271 9174 53.0788180 -27.8840956 ··· ··· 25.209 24.6149 22.6989 22.6498 10080 53.0846342 -27.6787341 ··· ··· 25.4273 24.2658 20.4466 20.3317 10329 53.0862593 -27.9171509 ··· ··· 24.1565 23.0951 22.5068 23.0143 10394 53.0866822 -27.8623509 ··· ··· 22.0993 21.1842 20.9623 21.392 10532 53.0875854 -27.8059688 ··· ··· 26.6729 26.7683 25.214 25.368 11180 53.0913824 -27.7591850 ··· ··· 26.4941 26.2619 24.3855 24.7926 11735 53.0946419 -27.8651134 ··· ··· 26.2469 25.9422 24.2736 24.8313 11861 53.0953488 -27.7909903 ··· ··· 25.1154 25.0229 23.674 24.0659 12689 53.1004690 -27.6839079 ··· ··· 24.242 23.3644 23.2883 23.7935 12725 53.1006978 -27.7030501 ··· ··· 22.4477 21.1734 20.4384 20.9233 14042 53.1079230 -27.7281237 ··· ··· 19.8459 18.9729 18.7334 19.1421 14089 53.1081764 -27.8251225 ··· ··· 26.4395 26.0328 22.7071 22.7131 14367 53.1094150 -27.7923849 ··· ··· 27.0351 27.1634 25.7172 25.4883 16226 53.1190121 -27.6821506 ··· ··· 25.7038 25.6801 24.6311 25.0638 16327 53.1195326 -27.6865159 ··· ··· 26.1646 26.1522 24.5148 24.9238 16819 53.1220450 -27.9387382 ··· ··· 25.2529 25.0962 22.5584 22.4439 18249 53.1294908 -27.8549550 ··· ··· 26.4309 26.3028 24.7144 24.8363 18488 53.1307275 -27.8038359 ··· ··· 26.4091 26.0292 24.8264 25.2949 20041 53.1394796 -27.8416660 ··· ··· 26.5863 25.9247 23.8694 23.9555 232 Table C.3 (cont’d) ID RA (◦ ) Dec (◦ ) B435 V606 i775 z850 IRAC3.6 IRAC4.5 22860 53.1547388 -27.7273906 ··· ··· 26.8387 26.5717 24.4105 24.6226 23254 53.1570620 -27.9128992 ··· ··· 24.6238 23.5813 23.1918 23.6706 23411 53.1579429 -27.8919595 ··· ··· 26.0112 25.198 21.5744 21.6087 23497 53.1584600 -27.8549141 ··· ··· 23.0262 22.2085 22.0926 22.5376 23763 53.1600829 -27.8980152 ··· ··· 27.0211 26.9678 24.1618 24.4449 25733 53.1722753 -27.8119802 ··· ··· 26.5396 26.533 24.769 25.3782 25783 53.1725614 -27.8137130 ··· ··· 26.1062 26.2068 24.6437 24.5623 26200 53.1753128 -27.8198958 ··· ··· 24.6663 23.406 22.6456 23.1335 26380 53.1764075 -27.7011003 ··· ··· 26.3754 25.474 20.7582 20.7322 26522 53.1775958 -27.9080422 ··· ··· 26.2197 25.9032 23.992 24.641 26924 53.1804396 -27.7196121 ··· ··· 26.392 26.3645 24.7308 24.8651 28054 53.1892715 -27.9107010 ··· ··· 26.0315 25.2313 25.0963 24.6328 29098 53.1980764 -27.7987172 ··· ··· 26.4817 26.4417 25.0706 25.4982 31331 53.2195287 -27.9014149 ··· ··· 26.4979 26.3311 23.5546 23.9004 31377 53.2199494 -27.8571386 ··· ··· 25.3399 24.0927 23.4035 23.9605 31426 53.2203405 -27.9155001 ··· ··· 26.5319 26.0881 24.2581 24.6917 31875 53.2248886 -27.9145574 ··· ··· 26.4397 26.25 24.2827 24.8487 32312 53.2295099 -27.9040246 ··· ··· 25.2675 25.1103 23.1552 23.3669 32535 53.2324141 -27.8626100 ··· ··· 22.3252 21.3289 20.7975 21.2159 32656 53.2345408 -27.8920908 ··· ··· 25.3285 25.2365 24.8175 24.8689 32900 53.2382032 -27.8625039 ··· ··· 24.739 24.7037 24.2191 24.6297 33305 53.2458788 -27.8922815 ··· ··· 25.546 25.2588 23.3504 23.9082 233 Rafal Idzi was born on April 5th, 1977 in Philadelphia, Pennsylvania to Jan and Gabriella Idzi. He attended high school in Philadelphia, Pennsylvania, though he spent most of his formative years in Poland. He attended Pennsylvania State University and graduated with degrees in Astrophysics & Astronomy and Physics in May 1999. During his time at Penn State he did Pulsar research with Dr. Alex Wolszczan. Upon graduation from college he began his graduate studies in the Department of Physics and Astronomy at Johns Hopkins University. Between 2001 and 2002 he worked with Dr. B. .G. Anderson conducting Interstellar Medium studies. He then began work in 2003 with the GOODS team under the guidance of Dr. Henry Ferguson, and eventually started his dissertation work on the formation and evolution of high-redshift galaxies together with Dr. Henry Ferguson and Dr. Rachel Somerville at the Space Telescope Science Institute and Prof. Timothy Heckman at Johns Hopkins University. After completion of his doctorate in Astrophysics, Rafal will leave academia and pursue a different career path. 234