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ACS Calibration Status. Ken Sembach 27-October-2005. ACS Website http://www.stsci.edu/hst/acs. ACS Calibration Teams at STScI and ST-ECF. John Biretta Ralph Bohlin Marco Chiaberge Mauro Giavalisco Shireen Gonzaga Colin Cox Linda Dressel Andy Fruchter Ron Gilliland - PowerPoint PPT Presentation
Citation preview
1
Ken Sembach
27-October-2005
ACS Calibration Status
ACS Websitehttp://www.stsci.edu/hst/acs
KRS 2
John BirettaRalph Bohlin
Marco ChiabergeMauro GiavaliscoShireen Gonzaga
Colin CoxLinda DresselAndy FruchterRon Gilliland
Vera Kozhurina-PlataisJesús Maíz-Apellániz
ST-ECFRichard Hook
Martin KümmelSören LarsenJeremy Walsh
Ray LucasJennifer MackMax MutchlerCheryl PavlovskyCharles ProffittAdam Riess Kailash SahuKen SembachMarco SirianniNolan Walborn
ACS Calibration Teams at STScI and ST-ECF
• This talk is an overview of ACS calibration activities. See the many talks/posters here for more details. People listed below are good sources of information.
KRS 3
ACS Status / Operation• All modes continue to operate well
• Two-gyro performance nominal
• Calibration plan for Cycle 14• STScI team has reviewed plans from previous cycles• Continuing calibrations for most previous programs (ongoing usual
calibration activities) • New programs to bring SBC calibrations up to the standard of
HRC/WFC calibrations, to better characterize the ramp filters, ultraviolet narrow-band red leak, and to estimate T-dependence of QE, CTE, and hot pixel growth
• ACS usage charted on STScI metrics page• Provides information about most frequently used modes
• http://www.stsci.edu/hst/metrics/SiUsage
KRS 4
Cycle 14 - Routine Monitoring Programs
ID # PI Title Freq.
Orbits Acc
.Notes
Ext Int
10729 Sirianni CCD Daily Monitor 4/week 0 840 … Dark, bias creation
10730 Chiaberge External CTE Monitor 6 months 9 0 1% CTE loss calibration
10732 Mutchler Internal CTE Monitor yearly 0 35 1% Check against ground
10733 Cox CCD Hot Pixel Annealing 4 weeks 0 143 … Includes monthly CTE
10734 Cox CCD Post-Flash Verification yearly 0 4 … Tracks capability only
10735 Cox SBC MAMA Recovery as needed 0 4 … After irregular safing
10736 Maiz UV Contamination Monitor 6 months 4 2 1% SBC, HRC tracking
10737 Mack CCD Stability Monitor quarterly 13 0 1%L-flat, distortion,
photometry
10738 Mack Earth Flats weekly 0 52 <1% Tracks coronagraphic spot
10739 Bohlin Internal Flat Fields 4 months 0 44 <1% SBC components once
10740 BohlinPhoto-Spectrophot. Abs.
Cal.yearly 7 0 <1% Filter throughputs, QE
Total (Cycle 14 routine monitoring programs) 33 1124
KRS 5
Cycle 14 - Special Calibration Programs
ID # PI Title Freq.Orbits
Acc. NotesExt Int
10722 Maiz SBC Geometric Distortion once 6 4 0.1 pixBasic calibration of geometric distortion
10731 Chiaberge UV Narrow-Band Red Leak once 2 0 <10% Responds to failed early cal
10741 Suchkov Continuum L-Flats - Ramps once 3 0 1% Basic calibration of flats
10742 Fruchter Ramp, Grism Wavelengths once 4 0 2% Responds to failed early cal
10743 Larsen Improved for SBC Prism once 2 2 <0.5 pix Two QSOs (1400-1800 Å)
10771 SirianniCTE & QE with Temperature
once 12 12 ASCS support test
Total (Cycle 14 special calibration programs) 29 18
KRS 6
Cycle 13 - Special Calibration Programs
ID # PI Title Freq.Orbits
Acc. NotesExt Int
10378 Biretta Polarization Calibration once 12 0 1% Last visit in July ‘05
10391 LarsenWave, Flux for Prisms
SBC+HRConce 1 11 5% Last visit in Aug ‘05
10449 Cox SBC Filter Wheel Checkout once 0 7 Use program only if needed
10450 Sirianni Functional Test MEB2 Switch once 0 2 Use program only if needed
10453 Sirianni Short Annealing Test once 0 0 Adopted for routine use
10720 RiessMonochromatic PSF in the
Redonce 1 0 Recently submitted
Total (Cycle 13 special calibration programs) 14 20
KRS 7
Cycle 14 - Calibration Orbit Summary
Cycle 14 Orbits
External Internal Outsourced*
Total Time (routine + special) 62 1142 11
With contingency 67 1253 11
* Two programs (PI = Dolphin): ACS zero point verification / Faint standard calibration
KRS 8
Recent ACS ISRs• Grism wavelength calibration
• ISR 2005-08 (Larsen & Walsh)• CCD internal flat fields
• ISR 2005-09 (Bohlin & Mack)• SBC pixel-pixel flat field
• ISR 2005-04 (Bohlin & Mack)• Astrometric improvements
• ISR 2005-06 (Koekemoer et al.)• HRC polarimetry
• ISR 2005-10 (Kozhurina-Platais & Biretta)• Two-gyro calibrations
• I. Pointing Stability (ISR 2005-07; Koekemoer et al.)• II. Coronagraphic Performance (ISR 2005-05; Cox & Biretta)
SBC flatfield
Complete list of ISRs at http://www.stsci.edu/hst/acs/documents/isrs
KRS 9
ACS High Resolution Channel
• Typically accounts for ~15-20% of ACS observing time
• Two-gyro checkout PSF shape / stability See poster by Pavlovsky
• Updated internal flat fields ISR 2005-09; Bohlin & Mack See talk by Mack
• Flats for use with polarizer filters ISR 2005-10; Kozhurina-Platais
& Biretta• PSFs and distortion corrections
ISR 2004-15; Anderson & King
(NASA, ESA, and J. Garvin (NASA/GSFC)
KRS 10
August 2005
114 exposures3 clusters
- NGC 2298 - NGC 1891 - NGC 6752
October 2005
72 exposures1 cluster (CVZ) - NGC 6752
186 ACS/HRC exposuresMin (FWHM) = 1.89Avg (FWHM) = 2.00Max (FWHM) = 2.19
ACS Instrument Performance in Two-Gyro Mode is Excellent
Three-gyro historical dataAvg (FWHM) = 2.04±0.03
PSF analayses by M. Sirianni, C. Pavlovsky, R. Lucas
KRS 11
ACS Wide Field Channel
• Typically accounts for ~75-80% of ACS observing time
• Updated internal flat fields ISR 2005-09; Bohlin & Mack
• Astrometric accuracy using GSC2 See poster by Koekemoer, also
ISR 2005-06
• Photometric stability ISR 2004-17; Riess See also talk by Mack
• PSFs and distortion corrections See talk by Anderson
NASA, ESA and The Hubble Heritage Team (STScI/AURA)
KRS 12
ACS Solar Blind Channel
• Typically accounts for ~3% of ACS observing time
More attention w/ loss of STIS• New pixel-pixel flat field available
ISR 2005-04; Bohlin & Mack• Updated darks available
ISR 2004-14; Cox• New calibrations planned
Geometric distortion correction (see poster by Maíz-Apellániz)
Prism wavelength calibration• See SBC overview poster by Cox
et al.SBC flatfield
KRS 13
ACS Coronagraphy• Typically ~3-4% of ACS observing time• Coronagraphic flat fields
ISR 2004-16; Krist
• Two-gyro coronagraphy performance ISR 2005-05; Cox & Biretta
HD 216149 2-gyro F625WHD 130948A 2-gyro F625WHD 130948A 3-gyro F625W
1.8” spot
3.0” spot
KRS 14
ACS Grism/Prism Spectroscopy• In Cycle 14
~25% of HRC observing time ~9% of WFC observing time ~23% of SBC observing time
• Slitless spectroscopy with ACS Talks by Kümmel, Meurer, and Maíz-Apellániz
• Grism spectroscopy WFC/G800L wavelength calibration (ISR 2005-08; Larsen & Walsh) WFC and HRC G800L flat field and sensitivity (ISR 2005-02; Walsh & Pirzkal)
• Prism spectroscopy Prisms used more since shutdown of STIS New wavelength/flux calibrations (see poster by Larsen)
• Software improvements aXe spectral extraction of prism/grism data (see poster by Walsh)
KRS 15
QE & CTE Temperature Dependence
• 12 orbit study to determine T-dependence of CTE, QE, hot pixel growth, etc., has relevance for
Performance of ACS in the coming years (T may increase) Future CTE temperature/time dependent corrections Aft-Shroud Cooling System considerations for SM4
• Test scheduled for November (47 Tuc, GOODS-N) fields) will obtain data at the current operating temperature and colder/hotter temperatures
WFC: -81˚, -77˚ (current), and -74˚ C HRC: -86˚, -80˚ (current), and -76˚ C
KRS 16
Charge Transfer Efficiency
Effects of poor CTE: - Signal is lost during the readout
Lower S/NDegraded detection limit
- Some trapped charge is released on short time scales, creating tails
Increased noisePSF alteration
- CTE depends on the signal level, position, background, and time
Degradation of the Charge Transfer Efficiency (CTE) is a well known problem for space-operated CCDs.
A B
Parallelreadout
Serial Readout Even if only a very small part of the charge packet is left behind in each pixel-to-pixel transfer the effect is severe:
CTE=99.99 % after 2048 transfers results in loss of ~19% of the signal
Current parallel CTE (@1620 e-) is 99.997%
Low number of transfers High number of transfers
KRS 17
WFC Parallel CTE Variation with Time
KRS 18
ACS CCD Hot Pixel Growth
WFCWFC
years
%
Hot pixels continue to increase because of radiation damageto the CCDs.
Effects of hot pixels can be reduced by dithering exposures.
Monthly anneals heal most of the hot pixels (see poster by Marco Sirianni).
KRS 19
ACS Pipeline Calibrations (see talk by Max Mutchler)
• Most recent ACS pipeline improvements
• Emphasis on bias and dark calibrations, including hot pixels
• Reference file production and delivery
• Data quality flagging and monitoring
• Ramifications for downstream data reductions, e.g. drizzling
WFC Dark
WFC Bias
KRS 20
Automated ACS Bias and Dark Reference File Production, and Improved Detector Trend Analysis
Ray A. Lucas (STScI), Mike Swam (STScI), Max Mutchler (STScI), and Marco Siriarnni (ESA/STScI)
Automatic TriggeringBased on HST Schedule
Automated Retrieval ofRaw Data From STScI Data Archive
Automated Processing toMake Reference Biases and Darks from Raw Data
Automatic Copy of Daily Darks andStatistics to Storage Disk for Long- Term Trend Analysis
Files Delivered to OPUS and Archive For Use in Pipeline and OTFC
Users
KRS 21
ACS Documentation• Cycle 15 Instrument Handbook streamlining and updates
• Length reduced by ~15% (310 pages trimmed to 262) w/o loss of content• Some calibration plan reference material moved to ACS website• Indexing update to make information easier to access in both paper and electronic
versions of handbook • Released with Cycle 15 Call for Proposals
• Cycle 15 Data Handbook update planned• Minor updates to wording in various places and syntax in examples
KRS 22
ACS Press Releases(Comets, Planets, and Stars) Comet 9P/Tempel 1
Before and After Deep Impact
Debris Ring Reshaped By Planet Around Nearby Star
Hubble Makes Movie of Neptune's Dynamic Atmosphere
Hubble Tracks Ceres
ACS Press Releases(Black Holes and Supernovae)
Hubble Pinpoints Doomed Supernova Progenitor
Black Hole in Search of a Home
ACS Press Releases(Nebulae and Galaxies)
Hubble Spies a Zoo of Galaxies
Scattered Light from the Boomerang Nebula"Big Baby" Galaxies in the Newborn Universe
Hubble/Chandra Image SNR N132D in the LMC