TIPS/JIM March 15, 2012
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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:
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Charles Lajoie joined RIA branch working on MIRI
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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
The New CALACS!
Putting the electrons back where they belong!
Linda Smith and the ACS+ Team! 1
New CALACS! • 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!
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CTE correction! • 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
Post-SM4 Artifacts! • 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
ACS Observations of Saturn!
Cross talk! Bias shift!
Bias stripes!
Uncorrected!
Corrected! 5
Structure of new CALACS!
Raw Image Bias-shift correction Cross talk correction
All full frame! images!
Bias-stripe correction CTI correction Dark correction using standard DRK files Data Products: CRJ, FLT, DRZ
Dark correction using new DKC files Data Products: CRC, FLC, DRC
Standard CALACS! CTE-corr CALACS! 6
New CALACS Files! 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!
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New reference files: ! ! PCTETAB (CTE parameters)! DKC – CTE-corrected darks (1600)!
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Current Status! • 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!
The ACS+ Team! 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 10th! Birthday! ACS !!!
SM3B ACS Installation 7 March 2002!
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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/low, the DSI moves up and
down by a large/small 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
Post-SM4 Sensitivity Calibration of the STIS Echelle Modes 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 Order/ Decreasing Wavelength
Echelle Modes
Increasing Wavelength
Photometric Conversion Table (PHOTTAB) 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
Status following SM4 Net Counts
Pre-SM4 Flux Calibration on Post-SM4 Data (smoothed)
Making a new PHOTTAB 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
But its never that simple… 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
Bad Pixel Tables 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
Ripple Tables 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
Flux Anomaly Decreased throughput directly following SM4 in E140H and E230M
Flux Anomaly Cont. 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
Data not affected If affected, then flux of new data should be too high
Edge Orders 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
PHOTTAB Creation Find sensitivity for each order: Sensitivity = Observed Net Count Rate/Model Flux Exclude bad pixels and strong absorption lines
Sensitivity
PHOTTAB Creation 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
Spline
PHOTTAB Creation 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
Smooth
PHOTTAB Creation 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
Final Calibration
Changes in CalSTIS 2.38 Phottab: A DUMMY pedigree will still be extracted opt_elem
cenwave
sporder
sensitivity
pedigree
E140H
1343
287
DUMMY
E140H
1343
288
DUMMY
E140H
1343
289
DUMMY
E140H
1343
290
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
1343
289
dq array
net array
net_err array
0
0
E140H
1343
290
dq array
net array
net_err array
flux array
err array
Future Work: Blaze Function Shift Evolution
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
JWST Aperture Synthesis with NIRISS Non-Redundant Mask ~65 mas angular resolution imaging in F380M F430M & F480M
Anand Sivaramakrishnan 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
NIRISS (née TFI)
Fullerton
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F430M PSF CLEAR 65 mas pixels NIRISS Nyquist at 4 micron
F430M PSF NRM
(née TFI)
Primary Beam 40 pixels 2.5
WebbPSF Python module (Perrin)
Fullerton
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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 Wilner (CfA) NRAO Summer School notes
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Correlator τ
E2(t)
One fringe per antenna pair Visibility (amplitude) & phase
V12 = V12 exp{iφ12}
visibility
E1(t)
ONE VOLTAGE per antenna
τ
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ONE VOLTAGE V21 = V12 exp{-iφ12} per antenna
V12 = V12 exp{iφ12}
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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{iφ(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{iφ(u,v}
V = Abs(V ) displayed here φ array has same areas of data φ is still a FRINGE PHASE 17
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Good uv-coverage if you repeat an observation with~ 60 degrees rotation (2 months ± ~1 fortnight)
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MIRIAD
invert; clean; restore – using the normalized point source dirty map as clean 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
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MIRIAD
invert; clean; restore – using the normalized point source dirty map as clean 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, Flight and Sivaramakrishnan, McKernan, Ford, Lcurrent afrenière, Tuthill, Teuben & Kpossible oda 03/2012 future Gen2 Flight H2RG detectors 2. Develop exposure time estimates and observing templates 3. Simulate various 2-orient exposures (probably don t need more) 4. Introduce complicated structure in sky 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 ers – Fourier or Image plane?
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