NASA Hubble Space Telescope Daily Report # 4507
HUBBLE SPACE TELESCOPE DAILY REPORT # 4507
Continuing to collect World Class Science
PERIOD COVERED: UT December 13, 2007 (DOY 347)
OBSERVATIONS SCHEDULED
ACS/SBC 11215
New Sightlines for the Study of Intergalactic Helium: Dozens of High-Confidence, UV- Bright Quasars from SDSS/GALEX
The reionization of IGM helium is thought to have occurred at redshifts of z=3 to 4. Detailed study of HeII Lyman-alpha absorption toward a handful of QSOs at 2.7
FGS 11317
HST Cycle 16 & pre-SM4 FGS alignment check
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA calibration – CR Persistence Part 6
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 i mages. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.
NIC2/NIC1 11000
Evaporating Disks
Evaporation in the vicinity of an O star disrupts protoplanetary disks, as seen in the Orion proplyds. We have found a number of evaporating disks with Spitzer, which are in some ways more dramatic and better oriented for detailed study than the proplyds ? they have cometary tails extending up to 0.1 pc from the evaporation working surface. We will use Spitzer/IRS and HST/NICMOS to investigate these systems in more detail. We want to explore the excitation condition in the gas, both in the head and in the tail where possible. We will measure the effects of evaporation on the characteristic emission features of the dust. We also will use NICMOS to image them in detail, including mapping complex structures resolved in their tails at 24 microns
WFPC2 10884
The Dynamical Structure of Ellipticals in the Coma and Abell 262 Clusters
We propose to obtain images of 13 relatively luminous early type galaxies in the Coma cluster and Abell 262 for which we have already collected ground based major and minor axis spectra and images. The higher resolution HST images will enable us to study the central regions of these galaxies which is crucial to our dynamical modeling. The complete data set will allow us to perform a full dynamical analysis and to derive the dark matter content and distribution, the stellar orbital structure, and the stellar population properties of these objects, probing the predictions of galaxy formation models. The dynamical analysis will be performed using an up-to-date axi-symmetric orbit superposition code.
WFPC2 10915
ACS Nearby Galaxy Survey
Existing HST observations of nearby galaxies comprise a sparse and highly non-uniform archive, making comprehensive comparative studies among galaxies essentially impossible. We propose to secure HST’s lasting impact on the study of nearby galaxies by undertaking a systematic, complete, and carefully crafted imaging survey of ALL galaxies in the Local Universe outside the Local Group. The resulting images will allow unprecedented measurements of: {1} the star formation history {SFH} of a >100 Mpc^3 volume of the Universe with a time resolution of Delta[log{t}]=0.25; {2} correlations between spatially resolved SFHs and environment; {3} the structure and properties of thick disks and stellar halos; and {4} the color distributions, sizes, and specific frequencies of globular and disk clusters as a function of galaxy mass and environment. To reach these goals, we will use a combination of wide-field tiling and pointed deep imaging to obtain uniform data on all 72 galaxies within a volume-limited sample extending to ~3.5 Mpc, with an extension to the M81 group. For each galaxy, the wide-field imaging will cover out to ~1.5 times the optical radius and will reach photometric depths of at least 2 magnitudes below the tip of the red giant branch throughout the limits of the survey volume. One additional deep pointing per galaxy will reach SNR~10 for red clump stars, sufficient to recover the ancient SFH from the color-magnitude diagram. This proposal will produce photometric information for ~100 million stars {comparable to the number in the SDSS survey} and uniform multi- color images of half a square degree of sky. The resulting archive will establish the fundamental optical database for nearby galaxies, in preparation for the shift of high- resolution imaging to the near-infrared.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS: (None)
COMPLETED OPS REQUEST:
18163-2 – RMGA Calibration for December 2007
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 11 11
FGS REacq 05 05
OBAD with Maneuver 32 32
SIGNIFICANT EVENTS:
OPS Request 18163 was successfully executed on December 13, 2007 to perform an RMGA Calibration test. RMGA was powered on at GMT 347/22:00. PSEA testmode was executed from GMT 347/23:12 to 347/23:42 to collect RMGA analog drift rate data for bias estimates. This data collection period was about 30 minutes (15 iterations of PSEA testmode) and will be processed by SAC. Assessment will determine if the drift rates have changed enough to warrant a bias update in PSEA configuration memory.
