Status Report

NASA Hubble Space Telescope Daily Report #4241

By SpaceRef Editor
November 16, 2006
Filed under , ,
NASA Hubble Space Telescope Daily Report #4241


– Continuing to collect World Class Science

PERIOD COVERED: UT November 15, 2006 (DOY 319)



ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This programme will be for the entire lifetime of ACS. Changes from cycle 13:- The default gain for WFC is 2 e-/DN. As before bias frames will be collected for both gain 1 and gain 2. Dark frames are acquired using the default gain {2}. This program cover the period May, 31 2006- Oct, 1-2006. The first half of the program has a different proposal number: 10729.

ACS/WFC 10787

Modes of Star Formation and Nuclear Activity in an Early Universe Laboratory

Nearby compact galaxy groups are uniquely suited to exploring the mechanisms of star formation amid repeated and ongoing gravitational encounters, conditions similar to those of the high redshift universe. These dense groups host a variety of modes of star formation, and they enable fresh insights into the role of gas in galaxy evolution. With Spitzer mid-IR observations in hand, we have begun to obtain high quality, multi-wavelength data for a well-defined sample of 12 nearby {<4500km/s} compact groups covering the full range of evolutionary stages. Here we propose to obtain sensitive BVI images with the ACS/WFC, deep enough to reach the turnover of the globular cluster luminosity function, and WFPC2 U-band and ACS H-alpha images of Spitzer- identified regions hosting the most recent star formation. In total, we expect to detect over 1000 young star clusters forming inside and outside galaxies, more than 4000 old globular clusters in >40 giant galaxies {including 16 early-type galaxies}, over 20 tidal features, approximately 15 AGNs, and intragroup gas in most of the 12 groups. Combining the proposed ACS images with Chandra observations, UV GALEX observations, ground-based H-alpha imaging, and HI data, we will conduct a detailed study of stellar nurseries, dust, gas kinematics, and AGN.

NIC1 11063

NICMOS Focus Monitoring

This program is a version of the standard focus sweep used since cycle 7. It has been modified to go deeper and uses more narrow filters for improved focus determination. For Cycle14 a new source has been added in order to accomodate 2-gyro mode: the open cluster NGC1850. The old target, the open cluster NGC3603, will be used whenever available and the new target used to fill the periods when NGC3603 is not visible. Steps: a} Use refined target field positions as determined from cycle 7 calibrations b} Use MULTIACCUM sequences of sufficient dynamic range to account for defocus c} Do a 17-point focus sweep, +/- 8mm about the PAM mechanical zeropoint for each cameras 1 and 2, in 1.0mm steps. d} Use PAM X/Y tilt and OTA offset slew compensations refined from previous focus monitoring/optical alignment activities

NIC1/NIC2/NIC3 11060

NICMOS Photometric Stability Monitoring

This NICMOS calibration proposal carries out photometric monitoring observations during Cycle 15. The format is the same as the Cycle 14 version of the program {10725}, but a few modifications were made with respect to the Cycle 12 program 9995 and Cycle 13 program 10381. Provisions had to be made to adopt to 2-gyro mode {G191B2B was added as extra target to provide target visibility through most of the year}. Where before 4 or 7 dithers were made in a filter before we moved to the next filter, now we observe all filters at one position before moving to the next dither position. While the previous method was chosen to minimize the effect of persistence, we now realize that persistence may be connected to charge trapping and by moving through the filter such that the count rate increases, we reach equilibrium more quickly between charge being trapped and released. We have also increased exposure times where possible to reduce the charge trapping non-linearity effects.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

A new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS Cameras. The POST-SAA darks will be non-standard reference files available to users with a USEAFTER date/time mark. The keyword ‘USEAFTER=date/time’ will also be added to the header of each POST-SAA DARK frame. The keyword must be populated with the time, in addition to the date, because HST crosses the SAA ~8 times per day so each POST-SAA DARK will need to have the appropriate time specified, for users to identify the ones they need. Both the raw and processed images will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS science/calibration observations started within 50 minutes of leaving an SAA will need such maps to remove the CR persistence from the science images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC3 10899

Identifying z>7 galaxies from J-dropouts

NICMOS Parallel Imaging campaigns covered enough sky {250 pointings} with enough sensitivity in the 110W and 160W filters to identify 6 extremely red resolved sources which are prime candidates for J-band dropouts. Their complete absence of detectable J band flux can be caused by an opaque Lyman cut-off at z=8-10. We propose to followup these candidates with NICMOS imaging and jointly propose Spitzer IRAC photometry. Deep F110W and Spitzer/IRAC 3.5/4.8 micron imaging will confirm if any of these candidates are indeed Lyman Break galaxies observed less than 500 Myrs after the Big Bang. Genuine LBGs will remain undetected in F110W, while being detected with flat spectra in the IRAC bands. The combined SED will provide information about the stellar mass of these galaxies, and the possible presence of evolved stars or dust reddening. The proposed observations will be sensitive enough to detect the F110W flux from galaxies as red as {J-H}=2.8 {AB mags, 5 sigma}. If any of the candidates are detected with bluer colors, they will most likely be exceptional “Distant Red Galaxies” at z of 4 to 6. The proposed data will constrain the stellar populations of these extraordinarily red galaxies, which would be candidates for the earliest, most massive galaxies which formed.

S/C 11073

Checkout of ACS Three-Detector Operations

This proposal will perform a brief checkout of the ACS in with three-detectors {WFC/HRC/SBC} powered and available for science operations.


Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)


10514 – REAcq (2,3,2) failed due to Scan Step Limit Exceeded on FGS 2 REAcq (2,3,2) scheduled at 319/13:44:32-13:51:54 failed to RGA control due to Scan Step Limit Exceeded on FGS 2. OBAD #1 RSS value = 706.63 a-s. OBAD #2 RSS value = 3.92 a-s. OBAD MAP RSS value = 12.10 a-s.

10515 – GSacq(1,3,3) failed due to search radius limit exceeded GSacq(1,3,3) scheduled at 320/02:52:58 failed at 02:57:02 due to search radius limit exceeded on FGS 3. ESB “a05” was received. RSS value of OBAD2 was 9.68 a-s. REacq(1,3,3) scheduled at 320/04:21:19 also failed due to search radius limit exceeded on FGS 3. ESB “a05” was received. RSS value of MAP was 18.80 a-s. OBAD REacq(1,3,3) scheduled at 320/05:58:33 also failed due to search radius limit exceeded on FGS 3. ESB “a05” was received. RSS value of 2nd OBAD was 4.56 a-s.



                          SCHEDULED      SUCCESSFUL
FGS GSacq                04                       02
FGS REacq                07                       03
OBAD with Maneuver   22                       22


Flash Report “ACS SBC Detector, part 3”

ACS completed the second phase (~6 orbits) of its on-orbit evaluation of its newly modified 3-detector operational configuration (WFMAHVon) at ~319/20:00. During this second phase ACS obtained a series of SBC, HRC and WFC calibration images which will be evaluated by the ACS Science team to ensure there are no adverse affects due to this new 3-detector configuration. All temperatures, voltages, and currents stayed well within their operational ranges. ACS NSSC1 Event Flag #2 (prevents SBC stored commanding) was set via stored commanding after completing this second phase and will be cleared pending review of the results by the ACS HRC ARB prior to return of the SBC to normal observations.

SpaceRef staff editor.