Daily # 4264

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4264

PERIOD COVERED: UT December 20, 2006 (DOY 3354)

OBSERVATIONS SCHEDULED

ACS/HRC 10800

Kuiper Belt Binaries: Probes of Early Solar System Evolution

Binaries in the Kuiper Belt are a scientific windfall: in them we have
relatively fragile test particles which can be used as tracers of the
early dynamical evolution of the outer Solar System. We propose to
continue a Snapshot program using the ACS/HRC that has a demonstrated
discovery potential an order of magnitude higher than the HST
observations that have already discovered the majority of known
transneptunian binaries. With this continuation we seek to reach the
original goals of this project: to accumulate a sufficiently large
sample in each of the distinct populations collected in the Kuiper
Belt to be able to measure, with statistical significance, how the
fraction of binaries varies as a function of their particular
dynamical paths into the Kuiper Belt. Today's Kuiper Belt bears the
imprints of the final stages of giant-planet building and migration;
binaries may offer some of the best preserved evidence of that
long-ago era.

ACS/HRC 11041

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS. For cycle 15 the program will cover 18
months 12.1.06-05.31.08 and it has been divied into three different
proposal each covering six months. The three proposals are
11041-11042-11043.

ACS/HRC 11051

CCD Stability Monitor

This program will verify that the low frequency flat fielding, the
photometry, and the geometric distortion are stable in time and across
the field of view of the CCD arrays.

ACS/WFC 10829

Secular Evolution at the End of the Hubble Sequence

The bulgeless disk galaxies at the end of the Hubble Sequence evolve
at a glacial pace relative to their more violent, earlier-type
cousins. The causes of their internal, or secular evolution are
important because secular evolution represents the future fate of all
galaxies in our accelerating Universe and is a key ingredient to
understanding galaxy evolution in lower-density environments at
present. The rate of secular evolution is largely determined by the
stability of the cold ISM against collapse, star formation, and the
buildup of a central bulge. Key diagnostics of the ISM's stability are
the presence of compact molecular clouds and narrow dust lanes.
Surprisingly, edge-on, pure disk galaxies with circular velocities
below 120 km/s do not appear to contain such dust lanes. We propose to
obtain ACS/WFC F606W images of a well-selected sample of extremely
late-type disk galaxies to measure the characteristic scale size of
the cold ISM and determine if they possess the unstable, cold ISM
necessary to drive secular evolution. Our sample has been carefully
constructed to include disk galaxies above and below the critical
circular velocity of 120 km/s where the dust properties of edge-on
disks change so remarkably. We will then use surface brightness
profiles to search for nuclear star clusters and pseudobulges, which
are early indicators that secular evolution is at work, as well as
measure the pitch angle of the dust lanes as a function of radius to
estimate the central mass concentrations.

ACS/WFC 10835

Probing The Globular Cluster / Low Mass X-ray Binary Connection in
Early-type Galaxies At Low X-ray

Combined high-resolution imaging from Hubble and Chandra {CXO} has
revolutionized our understanding of extragalactic low-mass X-ray
binaries {LMXBs} and globular clusters {GCs}, yet their connection in
early-type galaxies has remained unstudied at the luminosities of the
Galactic LMXBs in GCs. NGC 4278 and 3379 will be the first two
prototypical elliptical galaxies with deep CXO observations enabling
the study of LMXBs at lower luminosities. We propose mosaic ACS
observations of both galaxies {5 fields per galaxy} that will provide
the most comprehensive view into the connection between GCs and LMXBs
in early-type galaxies. We will detect ~860 and ~270 GCs in all of NGC
4278 and NGC 3379, respectively. These two galaxies will have among
the greatest number of detected GC-LMXBs to date {~130 & 50} and will
include the faintest GC-LMXBs in a normal early-type galaxy. We will
measure the fraction of GCs which contain LMXBs, as a function of
X-ray luminosity, galactocentric distance, color, and GC half-light
radius. Using the radial profiles of optical light, GCs, and LMXBs, we
will determine the percentage of field LMXBs which may have originated
in GCs. We will use the measured GC properties over the entire extent
of both galaxies to constrain theories of GC formation and evolution.

ACS/WFC 10917

Afterglows and Environments of Short-Hard Gamma-Ray Bursts

Discovery of the first afterglows of short-hard bursts {SHBs} has led
to a revolution in our understanding of these events, strongly
suggesting that they originate in the mergers of compact-object
binaries. Capitalizing on this progress, we propose to pursue the next
generation of SHB observations with HST, tracking the decay of all
accessible SHB afterglows to late times and pinpointing the location
of several more within the context of their host galaxies. These
observations will allow quantitative analysis of progenitor lifetimes
and short burst environments, enable direct confrontation with
population synthesis models, and provide updated event rate estimates
for the LIGO and VIRGO gravitational-wave detectors that are now
coming on-line.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST-SAA darks will be
non-standard reference files available to users with a USEAFTER
date/time mark. The keyword 'USEAFTER=date/time' will also be added to
the header of each POST-SAA DARK frame. The keyword must be populated
with the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST-SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKSs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

NIC2, ACS/WFC 10802

SHOES-Supernovae, HO, for the Equation of State of Dark energy

The present uncertainty in the value of the Hubble constant {resulting
in an uncertainty in Omega_M} and the paucity of Type Ia supernovae at
redshifts exceeding 1 are now the leading obstacles to determining the
nature of dark energy. We propose a single, integrated set of
observations for Cycle 15 that will provide a 40% improvement in
constraints on dark energy. This program will observe known Cepheids
in six reliable hosts of Type Ia supernovae with NICMOS, reducing the
uncertainty in H_0 by a factor of two because of the smaller
dispersion along the instability strip, the diminished extinction, and
the weaker metallicity dependence in the infrared. In parallel with
ACS, at the same time the NICMOS observations are underway, we will
discover and follow a sample of Type Ia supernovae at z 1. Together,
these measurements, along with prior constraints from WMAP, will
provide a great improvement in HST's ability to distinguish between a
static, cosmological constant and dynamical dark energy. The Hubble
Space Telescope is the only instrument in the world that can make
these IR measurements of Cepheids beyond the Local Group, and it is
the only telescope in the world that can be used to find and follow
supernovae at z 1. Our program exploits both of these unique
capabilities of HST to learn more about one of the greatest mysteries
in science.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10565 - GSacq(1,3,1) failed to RGA control

At AOS 354/16:41:51 flags indicated that the GSacq(1,3,1) scheduled at
354/16:11:14 failed due to search radius limit exceeded on FGS 3. The
Map at 16:18:24 showed errors of V1=2.70, V2=9.52, V3=0.18 and
RSS=9.90.

10566 - GSAcq(2,1,2) failed to RGA Hold (Gyro Control)

The GSAcq(2,1,2) scheduled at 354/22:33:45 - 22:41:50 failed to RGA
Hold due to (QF2STOPF) stop flag indication on FGS-2. Pre-acquisition
OBADs showed (RSS) attitude correction values of 2643.66 and 5.33
arcseconds. Post-acquisition OBAD/MAP had 3-axis (RSS) error value of
1.48 arcseconds.

COMPLETED OPS REQUEST:
17975-0 - Adjust Battery 3 VTFE Curve to K1L4-50mV
17982-0 - Remove VTFE SSPC Branch Command from SMAC00

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 09 07
FGS REacq 05 05
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS:

Battery 3 VTFE Curve & SMAC00 Adjustment Flash Report:

On DOY 2006/354 at 13:15 GMT, Ops Request 17975 was successfully
executed to increase the Battery 3 VTFE curve to K1L4-50mV. This
change was implemented to account for the discrepancy with the Battery
3 calibration curve. EPS SEs will continue to closely monitor and
evaluate the system performance over the next few days. Follow-up
reports will be provided.

In addition, Ops Request 17982 was successfully executed to remove the
VTFE curve reset special branch command from SMAC00 such that the VTFE
curves will not be reset to K1L4 upon safemode entry.