1 Ken Sembach 27-October-2005 ACS Calibration Status ACS Website

KRS 2 John Biretta Ralph Bohlin Marco Chiaberge Mauro Giavalisco Shireen Gonzaga Colin Cox Linda Dressel Andy Fruchter Ron Gilliland Vera Kozhurina-Platais Jesús Maíz-Apellániz ST-ECF Richard Hook Martin Kümmel Sören Larsen Jeremy Walsh Ray Lucas Jennifer Mack Max Mutchler Cheryl Pavlovsky Charles Proffitt Adam Riess Kailash Sahu Ken Sembach Marco Sirianni Nolan 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

KRS 4 Cycle 14 - Routine Monitoring Programs ID #PITitleFreq. Orbits Acc. Notes ExtInt 10729SirianniCCD Daily Monitor4/week0840…Dark, bias creation 10730ChiabergeExternal CTE Monitor6 months901%CTE loss calibration 10732MutchlerInternal CTE Monitoryearly0351%Check against ground 10733CoxCCD Hot Pixel Annealing4 weeks0143…Includes monthly CTE 10734CoxCCD Post-Flash Verificationyearly04…Tracks capability only 10735CoxSBC MAMA Recoveryas needed04…After irregular safing 10736MaizUV Contamination Monitor6 months421%SBC, HRC tracking 10737MackCCD Stability Monitorquarterly1301% L-flat, distortion, photometry 10738MackEarth Flatsweekly052<1%Tracks coronagraphic spot 10739BohlinInternal Flat Fields4 months044<1%SBC components once 10740Bohlin Photo-Spectrophot. Abs. Cal. yearly70<1%Filter throughputs, QE Total (Cycle 14 routine monitoring programs)331124

KRS 5 Cycle 14 - Special Calibration Programs ID #PITitleFreq. Orbits Acc.Notes ExtInt 10722MaizSBC Geometric Distortiononce640.1 pix Basic calibration of geometric distortion 10731ChiabergeUV Narrow-Band Red Leakonce20<10%Responds to failed early cal 10741SuchkovContinuum L-Flats - Rampsonce301%Basic calibration of flats 10742FruchterRamp, Grism Wavelengthsonce402%Responds to failed early cal 10743Larsen Improved for SBC Prism once22<0.5 pixTwo QSOs ( Å) 10771SirianniCTE & QE with Temperatureonce12 ASCS support test Total (Cycle 14 special calibration programs)2918

KRS 6 Cycle 13 - Special Calibration Programs ID #PITitleFreq. Orbits Acc.Notes ExtInt 10378BirettaPolarization Calibrationonce1201%Last visit in July ‘ Larsen Wave, Flux for Prisms SBC+HRC once1115%Last visit in Aug ‘ CoxSBC Filter Wheel Checkoutonce07Use program only if needed 10450SirianniFunctional Test MEB2 Switchonce02Use program only if needed 10453SirianniShort Annealing Testonce00Adopted for routine use 10720Riess Monochromatic PSF in the Red once10Recently submitted Total (Cycle 13 special calibration programs)1420

KRS 7 Cycle 14 - Calibration Orbit Summary Cycle 14 Orbits ExternalInternalOutsourced* Total Time (routine + special) With contingency * Two programs (PI = Dolphin): ACS zero point verification / Faint standard calibration

KRS 8 Recent ACS ISRs Grism wavelength calibration ISR (Larsen & Walsh) CCD internal flat fields ISR (Bohlin & Mack) SBC pixel-pixel flat field ISR (Bohlin & Mack) Astrometric improvements ISR (Koekemoer et al.) HRC polarimetry ISR (Kozhurina-Platais & Biretta) Two-gyro calibrations I. Pointing Stability (ISR ; Koekemoer et al.) II. Coronagraphic Performance (ISR ; Cox & Biretta) SBC flatfield Complete list of ISRs at

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 ; Bohlin & Mack  See talk by Mack Flats for use with polarizer filters  ISR ; Kozhurina-Platais & Biretta PSFs and distortion corrections  ISR ; Anderson & King (NASA, ESA, and J. Garvin (NASA/GSFC)

KRS 10 August exposures 3 clusters - NGC NGC NGC 6752 October exposures 1 cluster (CVZ) - NGC ACS/HRC exposures Min (FWHM) = 1.89 Avg (FWHM) =2.00 Max (FWHM) = 2.19 ACS Instrument Performance in Two-Gyro Mode is Excellent Three-gyro historical data Avg (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 ; Bohlin & Mack Astrometric accuracy using GSC2  See poster by Koekemoer, also ISR Photometric stability  ISR ; 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 ; Bohlin & Mack Updated darks available  ISR ; 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 ; Krist Two-gyro coronagraphy performance  ISR ; Cox & Biretta HD gyro F625WHD A 2-gyro F625WHD A 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 ; Larsen & Walsh)  WFC and HRC G800L flat field and sensitivity (ISR ; 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/N Degraded detection limit - Some trapped charge is released on short time scales, creating tails Increased noise PSF 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 Parallel readout 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 e-) is % Low number of transfersHigh number of transfers

KRS 17 WFC Parallel CTE Variation with Time

KRS 18 ACS CCD Hot Pixel Growth WFC years % Hot pixels continue to increase because of radiation damage to 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 Triggering Based on HST Schedule Automated Retrieval of Raw Data From STScI Data Archive Automated Processing to Make Reference Biases and Darks from Raw Data Automatic Copy of Daily Darks and Statistics 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