TIPS/JIM
March 15, 2012
Agenda:
INS Division News (Margaret Meixner)
The New CALACS (Linda Smith) !
Post-SM4 Sensitivity Calibration of the STIS Echelle Modes (Azalee
Bostroem) !
Aperture Synthesis Imaging with JWST NIRISS’ Non-redundant Mask
(Anand Sivaramakrishnan) !
Next TIPS/JIM: April 19, 2012

INS NEWS
-New employees in INS since last TIPS in January:
•
Charles Lajoie joined RIA branch working on MIRI
•
Steve Penton joining COS, working remotely but will arrive at the Institute in early April

TIPS/JIM
March 15, 2012
Agenda:
INS Division News (Margaret Meixner)
The New CALACS (Linda Smith) !
Post-SM4 Sensitivity Calibration of the STIS Echelle Modes (Azalee
Bostroem) !
Aperture Synthesis Imaging with JWST NIRISS’ Non-redundant Mask
(Anand Sivaramakrishnan) !
Next TIPS/JIM: April 19, 2012

!
Putting the electrons back where they belong !
!
1

!
•   New version of CALACS will be released in April !
•   Includes pixel-based CTE correction !
•   Corrections for all post-SM4 electronic artifacts !
•   New data products !
•   New reference files !
2

!
!
•   New CALACS uses a refined version of the
Anderson & Bedin (2010) code !
•   Includes time and temperature dependence for CTE losses !
•   Improved correction at low levels !
•   Includes column-to-column correction !
•   Uses parallel processing !
3

!
•   Bias shift (banding at 0.02-0.3% of pixel signal due to a mis-match in pre-amplifiers) !
•   Bias striping (due to electronic 1/f noise in reference voltage) !
•   Cross talk between readout amplifiers
(present since installation) !
•   All of these are corrected in new CALACS !
4

!
Cross talk !
Bias shift !
Bias stripes !
Uncorrected !
Corrected !
5

Structure of new
CALACS !
Raw Image
Bias-shift correction
Cross talk correction
Bias-stripe correction
CTI correction
All full frame !
images !
Dark correction using standard DRK files
Dark correction using new DKC files
Data Products:
CRJ, FLT, DRZ
Data Products:
CRC, FLC, DRC
Standard CALACS !
CTE-corr CALACS !
6

!
3 pairs of products: !
!
★   _CRJ = Cosmic ray corrected FITS image !
★   _CRC = Cosmic ray and CTE-corrected FITS image !
!
★   _FLT = Flat-field corrected FITS image !
★   _FLC = Flat-field and CTE-corrected FITS image !
!
★   _DRZ = Drizzled FITS image !
★   _DRC = Drizzled CTE-corrected FITS image !
!
Any data file with a type ending in “ C ” will be the CTE-corrected equivalent of a standard CALACS file !
!
New reference files: !
PCTETAB (CTE parameters) !
DKC – CTE-corrected darks (1600) !
7

!
•   Code is finished !
•   Waiting for all DKC files to be delivered – end of this week !
•   Start OPUS regression testing next week !
•   OPUS release expected in April !

!
J. Anderson, A. Armstrong, R. Avila, L. Bedin, M. Chiaberge, M. Davis, B.
Ferguson, A. Fruchter, D. Golimowski, S. Gonzaga, N. Grogin, W. Hack, P.
L. Lim, R. Lucas, A. Maybhate, M. McMaster, S. Ogaz, L. Smith, A.
Suchkov, L. Ubeda !
Happy 10 th !
Birthday !
ACS !!
!
SM3B ACS Installation 7 March 2002 !
9

11

12

Review of Bias Shift
•   The DSI-mode of the CEB-R induces a signal-dependent bias shift that ranges
from 0.02% to 0.30% among the four WFC quadrants.
•   Two electronic components cause bias shift:
1. The AC filter (high pass filter) in the preamp.
2. The resistor mismatch in the dual slope integrator.
•   The AC filter causes the DC offset of the preamp signal to vary with signal
intensity. If many bright / dark
pixels are sampled consecutively, the average
DC offset rises / falls
.
•   The DC offset feeds the DSI, which integrates up for the reset (bias) level and
integrates down for the signal level. If offset is high /
down by a large / small low
, the DSI moves up and
amount. The mismatched resistors cause mismatched
gains in the up and down stages, and therefore a signal-dependent bias shift.
•   Bias shift can be analytically removed using a parametric algorithm developed
by Markus Loose (ML), but parameters must be tuned for each quadrant.
3/29/12

TIPS/JIM
March 15, 2012
Agenda:
INS Division News (Margaret Meixner)
The New CALACS (Linda Smith) !
Post-SM4 Sensitivity Calibration of the STIS Echelle Modes (Azalee
Bostroem) !
Aperture Synthesis Imaging with JWST NIRISS’ Non-redundant Mask
(Anand Sivaramakrishnan) !
Next TIPS/JIM: April 19, 2012

Azalee Bostroem
With help from: Ralph Bohlin, Alessandra Aloisi, Charles
Proffitt, Kenneth Hart, Phil Hodge

•   Grating disperses light vertically
•   Higher orders are chosen and dispersed horizontally
•   Orders have overlapping wavelength ranges
•   Allows for broadband high resolution spectroscopy
•   STIS has 4 modes medium and high resolution modes
Increasing Wavelength

—   Convert net count rate to flux
—   Models the shape of the blaze function of each order
—   Shape varies continuously with location on the detector and time
—   Temporal component can experience a discontinuity with instrument changes (e.g. switch from Side 1 to Side
2 electronics
—   Discontinuity expected following SM4
—   Program 11866 executed in Cycle 17 to characterize the echelle blaze function

Net Counts
Pre-SM4 Flux Calibration on Post-SM4 Data (smoothed)

—   Steps:
—   Divide net counts of each order by a model spectrum
—   Fit each order with a spline
—   Smooth splines across orders
—   Record smoothed nodes for each order of every central wavelength in a table

—   First PHOTTAB created using STScI CalSTIS calibrated data
—   Created grating dependent bad pixel tables
—   Created new ripple tables
—   Look for the E140H flux anomaly
—   Data not in current PHOTTAB not extracted

—   NUV Bad Pixel Table:
—   NUV corners are vignetted
—   Vignetting is grating dependent
—   Previously in flat field
—   Now in bad pixel table
—   FUV Bad Pixel Table:
—   Repeller wire across detector
—   Previously in flat field
—   Location is grating dependent
—   Now in bad pixel table
!

—   Echelle 2D scattered light background subtraction
—   Normalized blaze function
—   Only delivered once in
2002, no information on the creation
—   Solve issue in E140H data background subtraction

—   Decreased throughput directly following SM4 in
E140H and E230M

—   Observed again after MAMA shutdown in fall 2010
—   Not observed in next monitoring Observation: April
2010
—   Echelle Flux calibration program executed
November 28, 2009 - January 6, 2010

—   If affected, then flux of new data should be too high

—   When PHOTTAB was created in 2006, the program was taken at extreme mode select mechanism positions
—   Monthly offsetting turned off for Echelle data
—   Some orders are off the detector
—   CalSTIS will not extract data not in the PHOTTAB unless fluxcorr is set to omit
—   These orders were evaluated and included on an individual basis

—   Find sensitivity for each order:
—   Sensitivity = Observed Net Count Rate/Model Flux
—   Exclude bad pixels and strong absorption lines

—   Find sensitivity for each order:
—   Sensitivity = Observed Net Count Rate/Model Flux
—   Exclude bad pixels and strong absorption lines
—   Fit a 7 (9 for E230M) node spline to sensitivity for each order

—   Find sensitivity for each order:
—   Sensitivity = Observed Net Count Rate/Model Flux
—   Exclude bad pixels and strong absorption lines
—   Fit a 7 (9 for E230M) node spline to sensitivity for each order
—   Smooth spline nodes for each order in the cross dispersion direction

—   Find sensitivity for each order:
—   Sensitivity = Observed Net Count Rate/Model Flux
—   Fit a 7 (9 for E230M) node spline to sensitivity for each order
—   Smooth spline nodes for each order in the cross dispersion direction
—   Back out the TDS to reflect sensitivity at Launch
—   Extrapolate to infinite aperture and extraction box height

Phottab: A DUMMY pedigree will still be extracted opt_elem
E140H
E140H
E140H
E140H cenwave
1343
1343
1343
1343 sporder
287
288
289
290 sensitivity pedigree
DUMMY
DUMMY
DUMMY
INFLIGHT
X1D Table: Add net_err column, set flux, err = 0 for DUMMY pedigree opt_elem cenwave sporder dq net net_err flux err
E140H
E140H
1343
1343
289
290 dq array dq array net array net array net_err array net_err array
0 flux array
0 err array

TIPS/JIM
March 15, 2012
Agenda:
INS Division News (Margaret Meixner)
The New CALACS (Linda Smith) !
Post-SM4 Sensitivity Calibration of the STIS Echelle Modes (Azalee
Bostroem) !
Aperture Synthesis Imaging with JWST NIRISS’ Non-redundant Mask
(Anand Sivaramakrishnan) !
Next TIPS/JIM: April 19, 2012

ʼ
~65 mas angular resolution imaging in F380M F430M & F480M
STScI , JWST NIRISS Science Team, JAM lead
Saavik Ford, Barry McKernan
City University of New York
David Lafrenière
University of Montréal, JWST NIRISS Science Team
Peter Tuthill
University of Sydney
1

Fullerton
2

F430M PSF CLEAR F430M PSF NRM
65 mas pixels
Nyquist at 4 micron
Primary Beam 
40 pixels
2.5
”
WebbPSF Python module (Perrin)
Fullerton
3

Wilner (CfA) NRAO Summer School notes
4

Wilner (CfA) NRAO Summer School notes
5

Wilner (CfA) NRAO Summer School notes
6

Wilner (CfA) NRAO Summer School notes
7

Wilner (CfA) NRAO Summer School notes
8

Wilner (CfA) NRAO Summer School notes
9

Wilner (CfA) NRAO Summer School notes
10

Wilner (CfA) NRAO Summer School notes
11

Wilner (CfA) NRAO Summer School notes
12

13

E
1
(t)
Correlator τ
E
2
(t)
One fringe per antenna pair
Visibility (amplitude) & phase
V
12
= V
12
exp{i φ
12
}
τ 14

V
21
= V
12
exp{-i φ
12
V
12
= V
12
exp{i φ
12
}
15

Subapertures in pupil
Image on detector
Each pixel points to different part of sky,
acts like a different τ in correlator
Pixel records square of electric field
Fourier transform image data
V
= V( u,v ) exp{i φ ( u,v }
V = Abs( V ) displayed here
φ array has same areas of data
φ is still a FRINGE PHASE
16

Subapertures in pupil
Image on detector
Each pixel points to different part of sky,
acts like a different τ in correlator
Pixel records square of electric field
Fourier transform image data
V
= V( u,v ) exp{i φ ( u,v }
V = Abs( V ) displayed here
φ array has same areas of data
φ is still a FRINGE PHASE
17

18

19

20

21

Good uv-coverage if you repeat an observation with~ 60 degrees rotation (2 months ± ~1 fortnight)
22

MIRIAD invert ; clean ; restore – using the normalized point source dirty map as clean ʼ s beam !
AGN  with  bar.
Integrated  magnitude  of  bar  is  1  mag  fainter   than  AGN  core
Bar  length  7  pix  ~  3.5
λ
/D
=  500  mas
=  25pc  @10Mpc
Sivaramakrishnan,  McKernan,  Ford,  Lafrenière,  Tuthill,  Teuben  &  Koda    03/2012
23

MIRIAD invert ; clean ; restore – using the normalized point source dirty map as clean ʼ s beam !
AGN  with  bar.
Integrated  magnitude  of  bar  is  1  mag  fainter   than  AGN  core
Bar  length  7  pix  ~  3.5
λ
/D
=  500  mas
=  25pc  @10Mpc
1.
Add noise to data, current Flight and possible future Gen2 Flight H2RG detectors
2.
Develop exposure time estimates and observing templates
3.
Simulate various 2-orient exposures (probably don ʼ t need more)
4.
Introduce complicated structure ʻ in sky ʼ
5.
Use full aperture PSFs in mosaicing?
6.
Deliver our IDL + python(MIRIAD) pipeline (or algorithm definition) to STScI
7.
Develop science cases for eg SODRM/GTO observations
8.
Refine data simulator
9.
Encourage advances in algorithms by NG NRM ʼ ers – Fourier or Image plane?
24