DAILY REPORT # 4157

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4157

PERIOD COVERED: UT July 17, 2006 (DOY 198)

OBSERVATIONS SCHEDULED

ACS/HRC 10598

ACS Imaging of Fomalhaut: A Rosetta Stone for Debris Disks Sculpted by
Planets

The Sun and roughly 15% of stars are surrounded by dust disks
collisionally replenished by asteroids and comets. Disk structure can
be directly tied to the dynamical influence of more massive bodies
such as planets. For example, planetary perturbations offset the
center of our zodiacal dust disk ~0.01 AU away from the Sun and also
maintain a ~40 AU radius inner edge to our Kuiper Belt. Here we
propose follow-up observation to the first optical detection of
reflected light from dust grains surrounding the nearby star Fomalhaut
using HST/ACS. We find a belt of material between 133 and 158 AU
radius that has a center position offset ~15 AU from the stellar
position, and with a sharp inner edge. A tenuous dust component
interior to the belt is also detected in the southeast. Given
Fomalhaut's proximity to the Sun {7.7 pc}, these images represent the
closest and highest angular resolution view of an extrasolar analog to
our Kuiper Belt. The center of symmetry offset and the sharp inner
edge of Fomalhaut's belt are evidence for planet-mass objects orbiting
the star as predicted by dynamical theory and simulations. We propose
comprehensive follow-up ACS imaging to fully exploit this discovery
and map the disk around its entire circumference with higher
signal-to-noise and at multiple wavelengths. HST/ACS is certainly the
only facility capable of performing this relatively wide field optical
study at high contrast ratios and diffraction-limited resolution. The
Cycle 14 data will provide key measurements of belt width as a
function of azimuth, the scattered light color of the belt versus the
inner dust component, and the azimuthal structure of the belt. These
data will be used to constrain dynamical models of resonances and
shepherding that ultimately elucidate the dynamical properties of
planet-mass objects in the system.

ACS/HRC 10801

Direct Determination of Kuiper Belt Object Diameters with HST

When it comes to fundamental properties of an astronomical object, it
is difficult to think of a more fundamental physical property than its
size. Because of their distance, objects in the Kuiper Belt are
generally too small for their disks to be resolved. The heterogeneous
albedo and color of the Kuiper Belt population makes size estimates
from observed absolute magnitude highly uncertain. And the
long-awaited data from the Spitzer Space Telescope suffers from our
ignorance of crucial macro- and micro-physical properties such as spin
period, pole orientation, surface roughness, and thermal inertia. We
propose to add a new dimension to the measurement of KBO diameters by
employing two techniques that will directly measure the diameters of
three large KBOs. We expect to obtain diameter measurements with
uncertainties of 10% or better and utilize these to validate and cross
calibrate the growing web of diameter measurements for KBOs.

ACS/HRC 11004

The 2006 outburst of RS Oph - A rapidly evolving SNR analogue with
jets

We propose to use HST DD time to perform high resolution optical
imaging of the 2006 outburst of the Recurrent Nova RS Ophiuchi, which
underwent its last recorded outburst in 1985. In this system, high
velocity ejecta impact a red giant wind setting up shock systems
analogous to a SNR, but evolving on months timescales. HST
observations will complement our multi-frequency observing campaign,
in particular our unrivalled coverage of this event with VLBI. In the
radio, we have resolved on AU scales the expanding shock front
responsible for the X-ray emission seen in the data from 4 satellites.
We have also detected jets on 0.1 arcsec scales. HST ACS HRC imaging
will be uniquely valuable in disentangling different emission
components and deriving physical conditions.

ACS/HRC/WFC 10758

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. Changes from cycle 13:- The default
gain for WFC is 2 e- /DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period May, 31 2006- Oct, 1- 2006.
The first half of the program has a different proposal number: 10729.

ACS/HRC/WFC 10896

An Efficient ACS Coronagraphic Survey for Debris Disks around Nearby
Stars

We propose to finish our Cycle 11 optical survey for nearby debris
disks using the ACS/HRC coronagraph. Out of 43 orbits originally
proposed for the survey, 23 orbits were allocated, leading to a survey
of 22 stars, from which two new debris disks were imaged for the first
time. Our analysis of the initial survey gives an empirical estimate
for the detection rate of debris disks relative to heliocentric
distance and dust optical depth. Our target list for Cycle 15 is now
optimized to yield more frequent disk detections. Likewise our
observing strategy is improved to maximize sensitivity per telescope
orbit allocated. Therefore we present the most efficient survey
possible. The scientific motivation is to obtain scattered light
images of previously unresolved debris disks to determine their
viewing geometry and physical architecture, both of which may
characterize the underlying planetary system. We choose 25 debris disk
targets for which we predict a detection rate of 25% ? 5%. Four
targets have extrasolar planets from which the viewing geometry
revealed by a disk detection will resolve the v sin{i} ambiguity in
the planet masses. These targets present the remarkable opportunity of
finally seeing a debris disk in system with known planets.

ACS/WFC 10490

A Snapshot Survey of a Complete Sample of X-ray Luminous Galaxy
Clusters from Redshift 0.3 to 0.7 We propose to extend a public,
uniform imaging survey of a well-studied, complete, and homogeneous
sample of X-ray clusters. The sample of 72 clusters spans the redshift
range between 0.3-0.7 and almost 2 orders of magnitude of X-ray
luminosity, with a median luminosity of 10^44 erg/s {0.5-2.0 keV}.
These snapshots will be used to obtain a fair census of the
morphologies of cluster galaxies in the cores of intermediate redshift
clusters, to detect radial and tangential arc candidates, to detect
optical jet candidates, and to provide an approximate estimate of the
shear signal of the clusters themselves and a potential assessment of
the contribution of large scale structure to lensing shear.

ACS/WFC 10587

Measuring the Mass Dependence of Early-Type Galaxy Structure

We propose two-color ACS-WFC Snapshot observations of a sample of 118
candidate early-type gravitational lens galaxies. Our lens-candidate
sample is selected to yield {in combination with earlier results} an
approximately uniform final distribution of 40 early-type strong
lenses across a wide range of masses, with velocity dispersions {a
dynamical proxy for mass} ranging from 125 to 300 km/s. The proposed
program will deliver the first significant sample of low-mass
gravitational lenses. All of our candidates have known lens and source
redshifts from Sloan Digital Sky Survey data, and all are bright
enough to permit detailed photometric and stellar-dynamical
observation. We will constrain the luminous and dark-matter mass
profiles of confirmed lenses using lensed-image geometry and
lens-galaxy structural/photometric measurements from HST imaging in
combination with dynamical measurements from spatially resolved
ground-based follow- up spectroscopy. Hence we will determine, in
unprecedented detail, the dependence of early-type galaxy mass
structure and mass-to-light ratio upon galaxy mass. These results will
allow us to directly test theoretical predictions for halo
concentration and star-formation efficiency as a function of mass and
for the existence of a cuspy inner dark-matter component, and will
illuminate the structural explanation behind the fundamental plane of
early-type galaxies. The lens-candidate selection and confirmation
strategy that we propose has been proven successful for high-mass
galaxies by our Cycle 13 Snapshot program {10174}. The program that we
propose here will produce a complementary and unprecedented lens
sample spanning a wide range of lens-galaxy masses.

ACS/WFC 10624

Solving the Mystery of the Short-Hard Gamma-Ray Bursts

Eight years after the afterglow detections that revolutionized studies
of the long-soft gamma-ray bursts, not even one afterglow of a
short-hard GRB has been seen, and the nature of these events has
become one of the most important problems in GRB research. The Swift
satellite, expected to be in full operation throughout Cycle 14, will
report few- arcsecond localizations for short-hard bursts in minutes,
enabling prompt, deep optical afterglow searches for the first time.
Discovery and observation of the first short-hard optical afterglows
will answer most of the critical questions about these events: What
are their distances and energies? Do they occur in distant galaxies,
and if so, in which regions of those galaxies? Are they the result of
collimated or quasi-spherical explosions? In combination with an
extensive rapid-response ground-based campaign, we propose to make the
critical high-sensitivity HST TOO observations that will allow us to
answer these questions. If theorists are correct in attributing the
short-hard bursts to binary neutron star coalescence events, then they
will serve as signposts to the primary targeted source population for
ground-based gravitational-wave detectors, and short-hard burst
studies will have a vital role to play in guiding those observations.

ACS/WFC/NIC2 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily
pre-scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.

CAL/ACS/SBC 11006

SBC Filter Wheel Checkout

In the event of an ACS Side 1 electronics failure we will switch to
Side 2. Several tests will be performed before resuming normal
operations. The following proposal is one of these and should be held
until the Side2 switch becomes necessary. This proposal's purpose is
to command the SBC Filter Wheel to each of its positions in both
directions of motion and verify {via the mechanism's positional
encoding readout} proper execution of the commands.

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.

WFPC2 10748

WFPC2 CYCLE 14 Standard Darks

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.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10365 - Reacq(1,2,1) results in finelock backup @198/1007z

During LOS REacq(1,2,1) scheduled at 198/10:06:39 rsulted in finelock
backup (1,0,1) due to a stop flag (QF2STOPF) on FGS 2. Observations
affected: ACS 38-41

10366 - Error Received while processing SAC-97 Procedure @197/1620z

After generating the engineering file for the SAC-97 - Gyro Bias
Trending: On Board Bias Validation procedure, an error was received
running the 'Trending Option of RGACAL'. The original time frame for
the engineering file covered the period 2006/189 00:00:00 to 197
00:00:00Z. The title of the error received is 'RAW DATA PROCESSING
ERROR' - error 30 accessing raw data file - message #3840.

10367 - Correctable Edac Errors @199/0420z

During Science Playback on SSR-1 we received 1363 Edacs from an
expected area already containing 131 errors. This total was generated
during a block range of approximately 16479 - 18099. After the On Call
SE was notified, FOT proceeded to redump the anamolous area and
received 1347 Edacs. These errors did not occur during an SAA. Fot
will notify SE when this area is written over and redumped.

COMPLETED OPS REQUEST:
17838-0 - GenSlew for Proposal 10598 slot#13 @198/1531z
17839-0 - GenSlew for Proposal 10598 slot#14 @198/1533z
17840-0 - GenSlew for Proposal 10598 slot#1 @198/1534z
17841-0 - GenSlew for Proposal 10598 slot#2 @198/1535z
17842-0 - GenSlew for Proposal 10598 slot#3 @198/1537z
17843-0 - GenSlew for Proposal 10598 slot#4 @198/1539z
17844-0 - GenSlew for Proposal 10598 slot#5 @198/2050z
17845-0 - GenSlew for Proposal 10598 slot#6 @198/2053z
17846-0 - GenSlew for Proposal 10598 slot#7 @198/2055z
17847-0 - GenSlew for Proposal 10598 slot#8 @198/2057z
17848-0 - GenSlew for Proposal 10598 slot#9 @198/2059z
17849-0 - GenSlew for Proposal 10598 slot#10 @198/2101z
17850-0 - GenSlew for Proposal 10598 slot#11 @198/2103z
17851-0 - GenSlew for Proposal 10598 slot#12 @198/2136z
17837-0 - CONTINGENCY: Disconnect and Mask the +CC SPA @199/0120z


COMPLETED OPS NOTES:
1508-1 - Battery Temperature Reaches 8 degC @199/0120z

SCHEDULED SUCCESSFUL
FGS GSacq 12 12
FGS REacq 02 02
OBAD with Maneuver 26 26
LOSS of LOCK

SIGNIFICANT EVENTS:

Offlined +CC SPA (K1A Trim Relay on Battery 6) Flash Report At
approximately doy 199 / 01:20 GMT (Monday, 7/17, 920pm local), the +CC
SPA was offlined to reduce battery 6 temperature. Battery 6
temperature had exceeded +8.4degC. EPS SE verified that the benchmark
reset threshold was reached on the following orbit and that the
battery 6 temperature had decreased by about 2degC relative to battery
5.