NASA Hubble Space Telescope Daily Report #4451
Notice: Due to the conversion of some ACS WFC or HRC observations into WFPC2, or NICMOS observations after the loss of ACS CCD science capability in January, there may be an occasional discrepancy between a proposal’s listed (and correct) instrument usage and the abstract that follows it.
HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science
DAILY REPORT # 4451
PERIOD COVERED: UT September 19, 2007 (DOY 262)
OBSERVATIONS SCHEDULED
NIC1/NIC2/NIC3 8794
NICMOS Post-SAA calibration – CR Persistence Part 5
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 DARKs. 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.
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.
WFPC2 11029
WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly Monitor
Intflat observations will be taken to provide a linearity check: the linearity test consists of a series of intflats in F555W, in each gain and each shutter. A combination of intflats, visflats, and earthflats will be used to check the repeatability of filter wheel motions. {Intflat sequences tied to decons, visits 1-18 in prop 10363, have been moved to the cycle 15 decon proposal xxxx for easier scheduling.} Note: long-exposure WFPC2 intflats must be scheduled during ACS anneals to prevent stray light from the WFPC2 lamps from contaminating long ACS external exposures.
WFPC2 11079
Treasury Imaging of Star Forming Regions in the Local Group: Complementing the GALEX and NOAO Surveys
We propose to use WFPC2 to image the most interesting star-forming regions in the Local Group galaxies, to resolve their young stellar populations. We will use a set of filters including F170W, which is critical to detect and characterize the most massive stars, to whose hot temperatures colors at longer wavelengths are not sensitive. WFPC2’s field of view ideally matches the typical size of the star-forming regions, and its spatial resolution allows us to measure individual stars, given the proximity of these galaxies. The resulting H-R diagrams will enable studies of star-formation properties in these regions, which cover largely differing metallicities {a factor of 17, compared to the factor of 4 explored so far} and characteristics. The results will further our understanding of the star-formation process, of the interplay between massive stars and environment, the properties of dust, and will provide the key to interpret integrated measurements of star-formation indicators {UV, IR, Halpha} available for several hundreds more distant galaxies. Our recent deep surveys of these galaxies with GALEX {FUV, NUV} and ground-based imaging {UBVRI, Halpha, [OIII] and [SII]} provided the identification of the most relevant SF sites. In addition to our scientific analysis, we will provide catalogs of HST photometry in 6 bands, matched corollary ground-based data, and UV, Halpha and IR integrated measurements of the associations, for comparison of integrated star-formation indices to the resolved populations. We envisage an EPO component.
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: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL FGS GSacq 07 07 FGS REacq 07 07 OBAD with Maneuver 28 28
SIGNIFICANT EVENTS: (None)
