Daily Report #4802

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** #4802

PERIOD COVERED: 5am March 2 - 5am March 3, 2009 (DOY
*************************** 061/1000z-062/1000z)

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.

WFPC2 11302

WFPC2 CYCLE 16 Standard Darks - Part III

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

WFPC2 11793

WFPC2 Cycle 16 Internal Monitor

This calibration proposal is the Cycle 15 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
(both gain 7 and gain 15 -- to test stability of gains and bias
levels), a test for quantum efficiency in the CCDs, and a monitor for
possible buildup of contaminants on the CCD windows. These also
provide raw data for generating annual super-bias reference files for
the calibration pipeline.

WFPC2 11972

Investigating the Early Solar System with Distant Comet Nuclei

We propose 85 orbits of imaging observations with the WFPC2 to get
nucleus size estimates for 8 well observed dynamically new and
long-period comets at large distances from the sun when their activity
levels are low. This will increase the sample of these nucleus sizes
by nearly 50%, but will more than double the selection of comets for
which we can run thermal models. Small icy bodies are the best
preserved remnants of planet formation, and we have recently found
that observationally constrained thermal models can distinguish
differences in microphysical properties of comet nuclei. The new HST
data will enable the first exploration of physical conditions in
different regions of the early solar nebula.

WFPC2 11978

Luminous and Dark Matter in Disk Galaxies from Strong Lensing and
Stellar Kinematics

The formation of realistic disk galaxies within the LCDM paradigm is
still an unsolved problem. Theory is only now beginning to make
predictions for how dark matter halos respond to galaxy formation and
for the properties of disk galaxies. Measuring the density profiles of
dark matter halos on galaxy scales is therefore a strong test for the
standard paradigm of galaxy formation, offering great potential for
discovery. However, from an observational point of view, the
degeneracy between the stellar and dark matter contributions to galaxy
rotation curves remains a major road block. Strong gravitational
lensing, when coupled to spatially-resolved kinematics and stellar
population models, can solve this long-standing problem.
Unfortunately, this joint methodology could not be exploited so far
due to the paucity of known edge-on spiral lenses. Exploiting the full
SDSS-DR7 archive we have identified a new sample of exactly these
systems. We propose multi-color HST imaging to confirm and measure a
sample of twenty spiral lenses, covering a range of bulge to disk
ratios. By combining dynamical lensing and stellar population
information for this unique sample we will deliver the first
statistical constraints on halos and disk properties, and a new
stringent test of disk galaxy formation theories.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

11703 - GSAcq(1,2,2) at 061/15:10z as well as REAcqs at 18:21z and
21:33z failed with FGS2 stop flag.

061/16:46z and 19:59z REAcqs were successful.

Observations affected: WFPC #31-34, #39-42 & 47-50, Proposal
ID#11972.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

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

FGS GSAcq*************** 03***************** 02
FGS REAcq*************** 11***************** 09
OBAD with Maneuver* **** 22***************** 22

SIGNIFICANT EVENTS: (None)