Galaxy Evolution Studies & the
NOAO Deep Wide-Field Survey
Arjun Dey
National Optical Astronomy Observatory
(for the NDWFS Team)
NDWFS Co-Investigators
Taft Armandroff, Ed Ajhar (Miami), Bob Blum, Todd Boroson, Kate Brand, Michael
Brown , Chuck Claver, Lindsey Davis, Ian Dell'Antonio (Brown), Mark Dickinson
(STScI), Richard Elston (U.o Fla.), Richard Green, Pat Hall (Princeton), Dan Hoard,
George Jacoby (WIYN), Dick Joyce, Tod Lauer , Roger Lynds, Sangeeta Malhotra
(STScI), Mike Merrill, Joan Najita, Earl O'Neil (Steward), Marc Postman (STScI),
Ron Probst, Travis Rector, James Rhoads (STScI), Robert Schommer, Nigel Sharp
(NSF), Malcolm Smith, Paul S. Smith (Steward), Glenn Tiede, Frank Valdes, Jeff
Valenti (STScI), Ted von Hippel (UofTexas), Alistair Walker, and Sidney Wolff.
Erin Ryan, Emma Hogan, Lissa Miller, Alyson Ford
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Arjun Dey
WMAP
Motivation
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?
M. Steinmetz
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Lacey & Cole
COBE
Arjun Dey
The Power of Wide-Field Surveys
Statistical approach to complex problems
Large samples
define population trends
statistically precise measurements
rare populations
Wide area
large scale clustering
less sensitive to cosmic variance
For example …
Features in the Color-Color Diagram
6.0
t=1Gyr BC03/Salpeter
BW-drops
z~3.5-4.2
Red envelope
population
BW-R
~0.6M galaxies
0
-0.5
R-I
2.5
Arjun Dey
Magnitude Slices in Color-Color Space
20-21
23-24
18-19
21-22
24-25
BW-R
17-18
19-20
22-23
R-I
25-26
Arjun Dey
The Redshift Distribution in the Color-Color Plane
Arjun Dey
Some Observations
•Galaxies in red envelope constitute ~ 10-12% of the objects (I<24.5)
•Most stars in red envelope population formed at high redshift (z>5)
•Narrow loop width suggests this population formed in a narrow
time interval and is coeval
•Small amounts of star formation persist to present-day:
field red population is not passively evolving (<1% of I<24.5)
(t-models with high zF are a reasonable fit; spectra show [OII])
A well-defined sample … and photo-z’s work well!
Arjun Dey
Our Photometric vs Spectroscopic zs
(see M. Brown’s talk for clustering results
and K. Brand’s talk for accretion history)
Arjun Dey
The Red Galaxy Sample: The Future
1.3 sq deg -> 18 sq deg!
Wow!
Arjun Dey
High-redshift galaxies in NDWFS
z~3.7
“BW-drops”
BW-R > 2.5
BW-R > 2(R-I)+1.7
R < 25
LALA
Bw-R
R-I
Arjun Dey
Comparisons with other high-z surveys
Steidel
z~3
Steidel
z~4
NDWFS
z~3.7
NDWFS
z~3.7
Area (sq deg)
0.38
0.23
0.36
18
# of candidates
2347
244
611
30,000
Spectroscopic redshifts
940
48
45
95.5%
65-80%
98%
0.68
0.20
0.47
17
10
<1>
2
26Mpc
29Mpc
68Mpc
1020Mpc
Hit rate
Surface density (arcmin-2)
# Contiguous fields
Max scale (comoving)
So stay tuned …
Arjun Dey
Spectroscopic Campaigns in the NDWFS Fields
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• MMT/Hectospec “AGES” (R<21 + X-ray sources)
• Keck/DEIMOS & LRIS (high-z + SIRTF sources)
• Gemini/GMOS (high-z + GALEX sources)
• WIYN/Hydra (QSOs + low-z line emitters)
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• WHT/WYFOS (QSOs)
• Spitzer/IRS (very red objects)
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The AGN and Galaxy Evolution Survey (AGES)
(C.S. Kochanek, D. Eisenstein PIs)
• Redshift survey using 300 fiber Hectospec on the MMT (Fabricant)
• Complete samples over most of NDWFS/Bootes field in:
•NDWFS R band
•all galaxies R19.2 mag (completed 4200 of 5500)
•random 20% of galaxies 19.2<R20 (completed 750 of 1400)
•for all galaxies 19.2<R20 completed 2100 of 7200
•NDWFS BW band (BW20.5, completed 2300 of 3000)
• SST/MIPS (Soifer)
•24m (F1mJy, completed 1100 of 1400)
•including point sources off stellar locus
•redshifts for 3100 24m sources in total (so far)
• SST/IRAC (Eisenhardt)
•3.6m (15.2mag, completed 1900 of 2300)
•4.5m (15.2mag, completed 2500 of 3000)
•5.8m (14.7mag, completed 1300 of 1600)
•8.0m (13.2mag, completed 1600 of 2100)
•redshifts for 7000 IRAC sources in total (so far)
• CXO/ACIS (Murray)
•FX41015ergs/cm2/s (completed 600 of 1000)
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C. Kochanek
~7100 redshifts so far; ~11,000 by June
redshift
1
Quasars
Galaxies
14
R mag
20
Color = template used to get redshift
Galaxy templates include absorption, star
formation and Seyfert components
C. Kochanek
K.A.O.S.!
Kilo-Aperture Optical Spectrograph
• Gemini prime focus spectrograph
–
–
–
–
1.5 degree field of view
~4800 fibers
12 spectrographs (4k x 4k CCDs)
Nod-and-shuffle sky subtraction
10-100 times better than any extant or
planned facility
http://www.noao.edu/kaos/
Arjun Dey
Thanks!
Motivation
How do galaxy formation and evolution depend upon (or
perhaps influence?) the formation and evolution of largescale structure?
Complexity of problem => statistical approaches
Need to track mass, Z, SFH, morphology, gas/stellar content,
accretion history as functions of time & environment
=> large samples
Structures on ~100h-1 Mpc scales! => large area
Arjun Dey