NASA Hubble Space Telescope Daily Report # 4535
HUBBLE SPACE TELESCOPE DAILY REPORT # 4535
Continuing to collect World Class Science
PERIOD COVERED: UT January 28, 2008 (DOY 028)
OBSERVATIONS SCHEDULED
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=3Ddate/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.
NIC3 11153
The Physical Nature and Age of Lyman Alpha Galaxies
In the simplest scenario, strong Lyman alpha emission from high redshift galaxies would indicate that stellar populations younger than 10 Myrs dominate the UV. This does not, however, constrain the stellar populations older than 100 Myrs, which do not contribute to UV light. Also, the Lyman alpha line can be boosted if the interstellar medium is both clumpy and dusty. Different studies with small samples have reached different conclusions about the presence of dust and old stellar populations in Lyman alpha emitters. We propose HST- NICMOS and Spitzer-IRAC photometry of 35 Lyman-alpha galaxies at redshift 4.5 NIC3 11195 Morphologies of the Most Extreme High-Redshift Mid-IR-luminous Galaxies II: The `Bump’ Sources The formative phase of some of the most massive galaxies may be extremely luminous, characterized by intense star- and AGN-formation. Till now, few such galaxies have been unambiguously identified at high redshift, and thus far we have been restricted to studying the low-redshift ultraluminous infrared galaxies as possible analogs. We have recently discovered a sample of objects which may indeed represent this early phase in galaxy formation, and are undertaking an extensive multiwavelength study of this population. These objects are optically extremely faint {R>26} but nevertheless bright at mid-infrared wavelengths {F[24um] > 0.5 mJy}. Mid-infrared spectroscopy with Spitzer/IRS reveals that they have redshifts z~2, implying luminosities ~1E13 Lsun. Their mid-IR SEDs fall into two broad, perhaps overlapping, categories. Sources with brighter F[24um] exhibit power-law SEDs and SiO absorption features in their mid-IR spectra characteristic of AGN, whereas those with fainter F[24um] show a “bump” characteristic of the redshifted 1.6um peak from a stellar population, and PAH emission characteristic of starformation. We have begun obtaining HST images of the brighter sources in Cycle 15 to obtain identifications and determine kpc-scale morphologies for these galaxies. Here, we aim to target the second class {the “bump” sources} with the goal of determining if these constitute morphologically different objects, or simply a “low-AGN” state of the brighter class. The proposed observations will help us determine whether these objects are merging systems, massive obscured starbursts {with obscuration on kpc scales!} or very reddened {locally obscured} AGN hosted by intrinsically low-luminosity galaxies. WFPC2 11083 The Structure, Formation and Evolution of Galactic Cores and Nuclei A surprising result has emerged from the ACS Virgo Cluster Survey {ACSVCS}, a program to obtain ACS/WFC gz imaging for a large, unbiased sample of 100 early-type galaxies in the Virgo Cluster. On subarcsecond scales {i.e., <0.1"-1"}, the HST brightness profiles vary systematically from the brightest giants {which have nearly constant surface brightness cores} to the faintest dwarfs {which have compact stellar nuclei}. Remarkably, the fraction of galaxy mass contributed by the nuclei in the faint galaxies is identical to that contributed by supermassive black holes in the bright galaxies {0.2%}. These findings strongly suggest that a single mechanism is responsible for both types of Central Massive Object: most likely internally or externally modulated gas inflows that feed central black holes or lead to the formation of "nuclear star clusters". Understanding the history of gas accretion, star formation and chemical enrichment on subarcsecond scales has thus emerged as the single most pressing question in the study of nearby galactic nuclei, either active or quiescent. We propose an ambitious HST program {199 orbits} that constitutes the next, obvious step forward: high-resolution, ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W} imaging for the complete ACSVCS sample. By capitalizing on HST's unique ability to provide high-resolution images with a sharp and stable PSF at UV and IR wavelengths, we will leverage the existing optical HST data to obtain the most complete picture currently possible for the history of star formation and chemical enrichment on these small scales. Equally important, this program will lead to a significant improvement in the measured structural parameters and density distributions for the stellar nuclei and the underlying galaxies, and provide a sensitive measure of "frosting" by young stars in the galaxy cores. By virtue of its superb image quality and stable PSF, NICMOS is the sole instrument capable of the IR observations proposed here. In the case of the WFPC2 observations, high-resolution UV imaging {< 0.1"} is a capability unique to HST, yet one that could be lost at any time. WFPC2 11198 Pure Parallel Imaging in the NDWFS Bootes Field The NOAO Deep-Wide Field Survey {NDWFS} Bootes field is the target of one of the most extensive multiwavelength campaigns in astronomy. In addition to ground-based optical and near-infrared imaging, deep radio mapping, and extensive spectroscopy, this entire region has been imaged by the Chandra, Spitzer {IRAC and MIPS}, and GALEX missions. Robust photometric redshifts {calibrated using over 20,000 spectroscopic redshifts} exist for all sources brighter than R=3D24.5 or than 13 uJy = at 4.5 microns. To enhance the value of this data set, we propose pure parallel observations for all approved Cycle 16 programs in this region that lack coordinated parallel observations. The primary aim of this program will be to provide a database useful for the broad range of science programs underway in this region. WFPC2 11339 A deep observation of NGC4261: understanding its unique X-ray source population, gas morphology, and jet properties The nearby early-type galaxy NGC4261 reveals strikingly asymmetric distributions of X-ray sources as seen with Chandra, and globular clusters (GC) as seen in the optical band. To address the link between these populations based on their spatial correlation, luminosity function and spectral properties, and to investigate the possibility that this effect is due to the galaxy’s merger history, we propose a 100ksec Chandra ACIS-S3 exposure, which will detect X-ray sources down to typical LMXB luminosities (Lx~5E37 erg/s), and HST-WFPC2 observations to obtain a deep census of the GC population over the whole galaxy. These data will also allow a detailed study of its complex gaseous component, and provide information on the unique two-sided X-ray jet. WFPC2 11020 Cycle 15 Focus Monitor The focus of HST is measured primarily with ACS/HRC over full CVZ orbits to obtain accurate mean focus values via a well sampled breathing curve. Coma and astigmatism are also determined from the same data in order to further understand orbital effects on image quality and optical alignments. To monitor the stability of ACS to WFPC2 relative focii, we’ve carried over from previous focus monitor programs parallel observations taken with the two cameras at suitable orientations of previously observed targets, and interspersed them with the HRC CVZ visits. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: 11163 – GSacq(2,0,2) failed to RGA control GSacq(2,0,2) scheduled at 028/10:32:17 failed during LOS. At AOS (10:52:55) stop flags QF2STOPF and QSTOP were set. The map at 10:37:58 showed errors of V1=3D-1.48, V2=3D-5.49, V3=3D8.53, and = RSS=3D10:25 COMPLETED OPS REQUEST: (None) COMPLETED OPS NOTES: (None) SIGNIFICANT EVENTS: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 11 10
FGS REacq 03 03
OBAD with Maneuver 28 28
