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Daily Report #4834
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT****** #4834 PERIOD COVERED: 5am April 15 - 5am April 16, 2009 (DOY *************************** 105/0900z-106/0900z) OBSERVATIONS SCHEDULED ACS/SBC 11980 Deep FUV Imaging of Cooling Flow Clusters We propose to take deep ACS FUV images of a carefully selected sample of 19 bright central galaxies in nearby galaxy clusters. This program is the last critical element of a comprehensive investigation of the impact of stellar and AGN feedback on the local galaxy cluster environment. The HST images will complement new, high-resolution, Halpha images obtained with the recently commissioned Maryland-Magellan Tunable Filter (MMTF) on the Baade 6.5m telescope, archival Chandra, VLA, and GALEX data, and on-going H2/NIR observations. The MMTF data have revealed unsuspected filamentary complexes in several systems. The GALEX data often show hints of extended NUV and FUV emission on a similar scale, but their poor spatial resolution prevents meaningful comparison with the MMTF data. The HST data will provide this much needed gain in resolution. The combined radio-H2-Halpha-FUV-X-ray dataset will allow us to derive with unprecedented precision the role of the AGN, hot stars, shocks, and relativistic particles on the excitation and thermodynamics of the multi-phase intracluster and interstellar media in these systems. This is an important question since the formation and evolution of most cluster galaxies have likely been affected by these processes. ACS/SBC 11982 Spanning the Reionization History of IGM Helium: a Large and Efficient HST Spectral Survey of Far-UV-Bright Quasars The reionization of IGM helium is thought to have occurred at redshifts of z=3 to 4. Detailed studies of HeII Lyman-alpha absorption toward a handful of QSOs at 2.7z3.3 demonstrated the high potential of such IGM probes, but the small sample size and redshift range limit confidence in cosmological inferences. The requisite unobscured sightlines to high-z are extremely rare, but we've cross-correlated 10, 000 z2.8 SDSS DR7 (and other) quasars with GALEX GR4 UV sources to obtain 550 new, high confidence, sightlines potentially useful for HST HeII studies; and in cycle 15-16 trials we demonstrated the efficacy of our SDSS/GALEX selection approach identifying 9 new HeII quasars at unprecedented 67% efficiency. We propose the first far-UV-bright HeII quasar survey that is both large in scale and also efficient, via 2-orbit reconnaissance ACS/SBC prism spectra toward a highly select subset of 40 new SDSS/GALEX quasars at 3.1z5.1. These will provide a community resource list that includes 5 far-UV-bright (restframe) HeII sightlines in each of 8 redshift bins spanning 3.1z3.9 (and perhaps several objects at z4), enabling superb post-SM4 follow-up spectra with COS or STIS. But simultaneously and independent of any SM4 uncertainties, we will hereby directly obtain 10-orbit UV spectral stacks from the 5 HeII quasars in each of the 8 redshift bins to trace the reionization history of IGM helium over at least 3.1z3.9. These spectral stacks will average over cosmic variance and individual object pathology. Our new high-yield HeII sightline sample and spectral stacks, covering a large redshift range, will allow confident conclusions about the spectrum and evolution of the ionizing background, the evolution of HeII opacity, the density of IGM baryons, and the epoch of helium reionization. FGS 11298 Calibrating Cosmological Chronometers: White Dwarf Masses We propose to use HST/FGS1R to determine White Dwarf {WD} masses. The unmatched resolving power of HST/FGS1R will be utilized to follow up four selected WD binary pairs. This high precision obtained with HST/FGS1R simply cannot be equaled by any ground based technique. This proposed effort complements that done by CoI Nelan in which a sample of WDs is being observed with HST/FGS1R. This proposal will dramatically increase the number of WDs for which dynamical mass measurements are possible, enabling a better calibration of the WD mass-radius relation, cooling curves, initial to final mass relations, and ultimately giving important clues to the star formation history of our Galaxy and the age of its disk as well as in other galaxies. {This project is part of Subasavage's PhD thesis work at Georgia State University.} FGS 11943 Binaries at the Extremes of the H-R Diagram We propose to use HST/Fine Guidance Sensor 1r to survey for binaries among some of the most massive, least massive, and oldest stars in our part of the Galaxy. FGS allows us to spatially resolve binary systems that are too faint for ground-based, speckle or optical long baseline interferometry, and too close to resolve with AO. We propose a SNAP-style program of single orbit FGS TRANS mode observations of very massive stars in the cluster NGC 3603, luminous blue variables, nearby low mass main sequence stars, cool subdwarf stars, and white dwarfs. These observations will help us to (1) identify systems suitable for follow up studies for mass determination, (2) study the role of binaries in stellar birth and in advanced evolutionary states, (3) explore the fundamental properties of stars near the main sequence-brown dwarf boundary, (4) understand the role of binaries for X-ray bright systems, (5) find binaries among ancient and nearby subdwarf stars, and (6) help calibrate the white dwarf mass - radius relation. WFPC2 11113 Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution The discovery of binaries in the Kuiper Belt and related small body populations is powering a revolutionary step forward in the study of this remote region. Three quarters of the known binaries in the Kuiper Belt have been discovered with HST, most by our snapshot surveys. The statistics derived from this work are beginning to yield surprising and unexpected results. We have found a strong concentration of binaries among low-inclination Classicals, a possible size cutoff to binaries among the Centaurs, an apparent preference for nearly equal mass binaries, and a strong increase in the number of binaries at small separations. We propose to continue this successful program in Cycle 16; we expect to discover at least 13 new binary systems, targeted to subgroups where these discoveries can have the greatest impact. WFPC2/ACS/SBC 11975 UV Light from Old Stellar Populations: a Census of UV Sources in Galactic Globular Clusters In spite of the fact that HST has been the only operative high-resolution eye in the UV-window over the last 18 years, no homogeneous UV survey of Galactic globular clusters (GGCs) has been performed to date. In order to fill this gap in the stellar population studies, we propose a program that exploits the unique capability of the WFPC2 and the SBC in the far-/mid- UV for securing deep UV imaging of 46 GGCs. The proposed observations will allow to study with unprecedented accuracy the hottest GGC stars, comprising the extreme horizontal branch (HB) stars and their progeny (the so-called AGB-manque', and Post-early AGB stars), and "exotic stellar populations" like the blue straggler stars and the interacting binaries. The targets have been selected to properly sample the GGC metallicity/structural parameter space, thus to unveil any possible correlation between the properties of the hot stellar populations and the cluster characteristics. In addition, most of the targets have extended HB "blue tails", that can be properly studied only by means of deep UV observations, especially in the far-UV filters like the F160BW, that is not foreseen on the WFC3. This data base is complemented with GALEX observations in the cluster outermost regions, thus allowing to investigate any possible trend of the UV-bright stellar types over the entire radial extension of the clusters. Although the hottest GGC stars are just a small class of "special" objects, their study has a broad relevance in the context of structure formation and chemical evolution in the early Universe, bringing precious information on the basic star formation processes and the origin of blue light from galaxies. Indeed, the proposed observations will provide the community with an unprecedented data set suitable for addressing a number of still open astrophysical questions, ranging from the main drivers of the HB morphology and the mass loss processes, to the origin of the UV upturn in elliptical galaxies, the dating of distant systems from integrated light, and the complex interplay between stellar evolution and dynamics in dense stellar aggregates. In the spirit of constructing a community resource, we entirely waive the proprietary period for these observations. 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************** 06**************** 06 FGS REAcq************** 08**************** 08 OBAD with Maneuver **** 28**************** 28 SIGNIFICANT EVENTS: (None) |
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