Daily Rpt #4778

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** #4778

PERIOD COVERED: 5am January 26 - 5am January 27, 2009 (DOY
*************************** 026/1000z-027/1000z)

OBSERVATIONS SCHEDULED

ACS/SBC 11681

A Search for Ultraviolet Emission Filaments in Cool Core Clusters

We propose to use ACS SBC imaging to seek ultraviolet CIV emission
filaments in clusters of galaxies exhibiting strong cool-core X-ray
emission and optical line emission filaments. These short observations
are crafted to test thermal conduction models for the filament
excitation, and can significantly impact our understanding of the
overall physical processes dominant in the galaxy cluster ISM.

ACS/SBC 11970

HST Observations of Titan's Escaping Atmosphere in Transit and in
Emission

We propose UV observations using the ACS/SBC of Titan's extended
escaping atmosphere for the Jan/Feb 2009 period of transits of Titan
across Saturn. A combination of absorption of Saturn's reflected solar
UV emission in transit, and extended emissions primarily from H atoms
away from transit, will yield new information about the structure of
Titan's extended upper atmosphere. These observations are expected to
provide new constraints on theoretical models for a hydrodynamic flow
of species through Titan's exobase level, resulting from the
interpretation of recent Cassini measurements at Titan.

WFPC2 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey
of a sample of 125 very X-ray luminous clusters in the redshift range
0.3-0.7. As demonstrated by the 25 snapshots obtained so far in
Cycle14 and Cycle15 these systems frequently exhibit strong
gravitational lensing as well as spectacular examples of violent
galaxy interactions. The proposed observations will provide important
constraints on the cluster mass distributions, the physical nature of
galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set
of optically bright, lensed galaxies for further 8-10m spectroscopy.
All of our primary science goals require only the detection and
characterization of high-surface-brightness features and are thus
achievable even at the reduced sensitivity of WFPC2. Because of their
high redshift and thus compact angular scale our target clusters are
less adversely affected by the smaller field of view of WFPC2 than
more nearby systems. Acknowledging the broad community interest in
this sample we waive our data rights for these observations.

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 11966

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 high
resolution observations (especially U-band and H-alpha) 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. We need to know the
ages, star formation histories, and extinction of these individual
clusters to understand how these clusters form and age and thus
influence the evolution of the galaxy. In this proposal we address
this missing area of SINGS by obtaining high-resolution WFPC2 UBVI &
H-alpha observations to not only accurately locate and determine the
ages of the young stellar clusters in the actively star forming SINGS
galaxies but to also address a variety of other scientific issues.
Over 500 HST orbits and 500 hours of Spitzter observing time have been
dedicated to observations of the SINGS sample. But the HST
observations have not been systematic. By adding a relatively small
fraction of this time for these requested observations, we will
greatly enhance the legacy value of the SINGS observations by creating
a uniform high resolution multi-wavelength HST archive that matches
the quality of the lower resolution SINGS archive.

WFPC2 11991

Constraining the Late Time Lightcurve and Energy of GRB 090102

We propose to conduct a series of late time observations of the
lightcurve of the bright gamma-ray burst GRB 090102. Declared a burst
of interest by the Swift team, and with excellent broadband data
covering the prompt emission (Swift and Fermi) and afterglow (Swift,
TAROT, NOT, WHT, and several more), GRB 090102 offers a rare
opportunity to probe the physics and energetics of GRBs. Its high
energy budget (2e53 ergs for isotropic emission) stretches plausible
progenitor models, and as yet the signatures of jet-like emission have
not been observed. Our late time observations will search for
steepening of the afterglow due to lateral expansion of the jet. This
will enable us, in tandem with the data already secured, to determine
its total energy budget, and compare this to expectations for
different progenitors models. HST is vital to this endeavour since it
can reach depths essentially unattainable to ground based technology,
while its invariant PSF will allow us to accurately remove underlying
host contamination. Ultimately, the range and quality of data secured
for this burst will enable us to accurately reconstruct the parameters
of the explosion, and shed greater light on the physical processes
which underlie the production of GRBs.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11649 - REACQ(2,3,2) at 026/23:57:47 failed to RGA control at
027/00:01:36 with QF2STOPF and QSTOP flags set.

Observations affected: WFPC 32 to 33, proposal 11966

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

************************ SCHEDULED***** SUCCESSFUL
FGS GSacq*************** 05***************** 05
FGS REacq*************** 07***************** 06
OBAD with Maneuver* **** 22***************** 22

SIGNIFICANT EVENTS: (None)