Daily Report #4821

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** #4821

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 2.7z3.3 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.

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)

*********************** SCHEDULED***** SUCCESSFUL

FGS GSAcq************** 19***************** 18
FGS REAcq************** 20***************** 19
OBAD with Maneuver **** 78***************** 78

SIGNIFICANT EVENTS: (None)