NASA Hubble Space Telescope Daily Report #4821
HUBBLE SPACE TELESCOPE DAILY REPORT #4821
Continuing to collect World Class Science
PERIOD COVERED: 5am March 27 – 5am March 30, 2009 (DOY 086/0900z-089/0900z)
OBSERVATIONS SCHEDULED
WFPC2 11987
The Recent Star Formation History of SINGS Galaxies
The Spitzer Legacy project SINGS provided a unique view of the current state of star formation and dust in a sample of galaxies of all Hubble types. This multi-wavelength view allowed the team to create current star formation diagnostics that are independent of the dust content and increased our understanding of the dust in galaxies. Even so, using the SINGS data alone we can only make rough estimates of the recent star formation history of these galaxies. The lack of U-band observations means that it is impossible to estimate the ages of young clusters. In addition, the low resolution of the Spitzer and ground-based observations means that what appear to be individual Spitzer sources can actually be composed of many individual clusters with varying ages. In this proposal we plan to address this missing area in SINGS by obtaining high-resolution WFPC2 UBVI observations to accurately find and determine the ages of the young stellar clusters in a subset of the SINGS galaxies. These observations will greatly enhance the legacy value of the SINGS observations while also directly answering questions pertaining to star formation in galaxies.
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 2.7
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.
WFPC2 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.
WFPC2 11974
High-resolution Imaging for 9 Very Bright, Spectroscopically Confirmed, Group-scale Lenses
There are large samples of strong lenses that probe small (galaxy) scale masses (e.g., SLACS, SQLS, COSMOS). There are also large samples of strong lenses that probe large (rich cluster) scale masses (e.g., various rich Abell clusters, the Hennawi et al. 2008 SDSS sample). The sample of strong lenses that probe intermediate (group/cluster-core) scale masses, however, is sparse, and so any significant additions to this sample are important. Here we present a sample of strong lenses that not only probe these intermediate scales but are also quite bright, since the sample is based almost entirely upon data from the SDSS, a relatively shallow and poor-resolution survey, at least in comparison to most other strong lens hunting grounds, such as COSMOS and CFHTLS. What we lack are the high-resolution imaging data needed to construct detailed lensing models, to probe the mass and light profiles of the lensing galaxies and their environments, and to characterize the morphologies of the lensed (source) galaxies. Only HST can provide these data, and so we are proposing here for 81 orbits of deep WFPC2 F450W, F606W and F814W imaging, for 9 of our best and brightest intermediate-scale lensing systems with known spectroscopic redshifts and with Einstein radii between 4 and 8 arcsec.
WFPC2 11944
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 to observe using 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.
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.
FGS 11790
HST/FGS Astrometric Search for Young Planets Around Beta Pic and AU Mic
AU Mic is a nearby Vega-type debris disk star. Its disk system has been spatially resolved in exquisite detail, predominantly via the ACS coronagraph and WFPC-2 cameras onboard HST. These images exhibit a wealth of morphological features which provide compelling indirect evidence that AU Mic likely harbors short-period planetary body(ies). We propose to use the superlative astrometric capabilities of HST/FGS to directly detect these planets, hence provide the first direct planet detection in a Vega-type system whose disk has been imaged at high spatial resolution.
WFPC2 11130
AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge Paradigm, Part II
The recent progress in the study of central black holes in galactic nuclei has led to a general consensus that supermassive {10^6-10^9 solar mass} black holes are closely connected with the formation and evolutionary history of large galaxies, especially their bulge component. Two outstanding issues, however, remain unresolved. Can central black holes form in the absence of a bulge? And does the mass function of central black holes extend below 10^6 solar masses? Intermediate-mass black holes {<10^6 solar masses}, if they exist, may offer important clues to the nature of the seeds of supermassive black holes. Using the SDSS, our group has successfully uncovered a new population of AGNs with intermediate-mass black holes that reside in low-luminosity galaxies. However, very little is known about the detailed morphologies or structural parameters of the host galaxies themselves, including the crucial question of whether they have bulges or not. Surprisingly, the majority of the targets of our Cycle 14 pilot program have structural properties similar to dwarf elliptical galaxies. The statistics from this initial study, however, are really too sparse to reach definitive conclusions on this important new class of black holes. We wish to extend this study to a larger sample, by using the Snapshot mode to obtain WFPC2 F814W images from a parent sample of 175 AGNs with intermediate- mass black holes selected from our final SDSS search. We are particularly keen to determine whether the hosts contain bulges, and if so, how the fundamental plane properties of the host depend on the mass of their central black holes. We will also investigate the environment of this unique class of AGNs.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
11744 – GSAcq (1,2,2) failed to RGA Hold due to QF1STOPF flag on FGS-1 @ 086/15:22:55z
Observations affected: WFPC 162 – 163, Proposal ID# 11974.
11745 – REAcq (1,2,2) failed due to FGS Sequential Attitude update being too large to correct @ 086/16:28z
Observations affected: WFPC 164 – 165, Proposal ID# 11974.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SIGNIFICANT EVENTS: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 19 18
FGS REAcq 20 19
OBAD with Maneuver 78 78
