Daily # 4184

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4184

PERIOD COVERED: UT August 23, 2006 (DOY 235)

OBSERVATIONS SCHEDULED

ACS/HRC 10738

Earth Flats

Sky flats will be obtained by observing the bright Earth with the HRC
and WFC. These observations will be used to verify the accuracy of the
flats currently in the pipeline and to monitor any changes. Weekly
coronagraphic monitoring is required to assess the changing position
of the spots.

ACS/HRC 10805

ACS Imaging of Uranus' Atmosphere Near Equinox

Uranus' 97-degree spin axis inclination results in the largest
fractional seasonal variation of solar insolation in the solar system.
Uranus is now close to its 7 December 2007 equinox, and we can now see
most of the northern hemisphere, which was in darkness when Voyager
provided our first detailed view of the planet in 1986. If Uranus'
seasonal response has the large phase shift expected from its long
radiative time constant, it should now exhibit nearly maximal
hemispheric contrast. Although the long time constant also suggests a
small physical response, significant hemispheric asymmetries in cloud
structure and dynamics are becoming apparent. We propose a detailed
characterization of Uranus' current response to this forcing with a
10-orbit program consisting of 4 orbits of WFC imaging with narrowband
ramp filters and 6 orbits of HRC imaging using both broadband and
narrowband filters. Nine narrow-band filters between 0.62 and 0.955
microns will provide vertical sensing depths scanning through the
pressure range where the putative methane and deeper H2S clouds might
plausibly exist and provide strong constraints on their optical
properties and parent gas mixing ratios. The high resolution HRC
images will characterize the dynamics of discrete features at the
15-30 hour time scale unavailable from the ground. Short wavelength
HRC images will enable a characterization of the stratospheric haze.
These observations have unique combinations of spectral range and
resolution with needed temporal and spatial resolution not available
from groundbased observations.

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/SBC 10184

A New Class of Bright Ultraviolet Variable Sources in the Globular
Cluster NGC 1851

Our reductions of archival STIS/FUV-MAMA data {AR9225} have discovered
13 completely unexpected and unexplained Ultraviolet bright variables.
Eleven of the variables have been identified with evolved stars
{Horizontal Branch or Asymptotic Giant Branch}. The total number and
nature of these systems is completely unknown. If these variables are
binaries the implication is that the binary fraction {up to 25%} in
NGC 1851 is the highest in all Galactic globular clusters. The radial
distributions of the variables and the blue horizontal branch stars
imply a common origin and perhaps an explanation of the bi-modal
morphology of the horizontal branch in the color magnitude diagrams of
globular clusters. These variables may be the tip of the iceberg and a
critical clue concerning the infamous "second parameter". We propose
to observe NGC 1851 on three occasions with the same setup as the
archival data to determine the total number and periods of the
ultraviolet variables.

ACS/WFC 10816

The Formation History of Andromeda's Extended Metal-Poor Halo

We propose deep ACS imaging in the outer spheroid of the Andromeda
galaxy, in order to measure the star formation history of its true
halo. For the past 20 years, nearly all studies of the Andromeda
"halo" were focused on the spheroid within 30 kpc of the galaxy's
center, a region now known to host significant substructure and
populations with high metallicity and intermediate ages. However, two
groups have recently discovered an extended metal-poor halo beyond 30
kpc; this population is distinct in its surface-brightness profile,
abundance distribution, and kinematics. In earlier cycles, we obtained
deep images of the inner spheroid {11 kpc on the minor axis}, outer
disk {25 kpc on the major axis}, and giant tidal stream, yielding the
complete star formation history in each field. We now propose deep ACS
imaging of 4 fields bracketing this 30 kpc transition point in the
spheroid, so that the inner spheroid and the extended halo populations
can be disentangled, enabling a reconstruction of the star formation
history in the halo. A wide age distribution in the halo, as found in
the inner spheroid, would imply the halo was assembled through ongoing
accretion of satellite galaxies, while a uniformly old population
would be a strong indication that the halo was formed during the early
rapid collapse of the Andromeda proto-galaxy.

ACS/WFC 10881

The Ultimate Gravitational Lensing Survey of Cluster Mass and
Substructure

We propose a systematic and detailed investigation of the mass,
substructure, and thermodynamics of one hundred X-ray luminous galaxy
clusters at 0.15z0.3. The primary goal is to test our recent
suggestion that this population is dominated by dynamically immature
disturbed clusters, and that the observed mass-temperature relation
suffers strong structural segregation. If confirmed, this would
represent a paradigm shift in our observational understanding of
clusters, that were hitherto believed to be dominated by mature,
undisturbed systems. The key observation to this endeavor is Hubble
imaging of cluster cores to identify robustly tangential and radial
multiple arcs and measure the shape of faint galaxies. These strong
and weak lensing signals will give an accurate measure of the total
mass and structure of the dark matter distribution that we will
subsequently compare with X-ray and Sunyaev Zeldovich Effect
observables. The broader applications of our project include 1} the
calibration of mass-temperature and mass-SZE scaling relations which
will be critical for the calibration of proposed dark energy
experiments, and 2} the low redshift baseline study of the
demographics of massive clusters to aid interpretation of future high
redshift {z1} cluster samples. For this ultimate cluster survey, we
request ACS SNAPSHOTS through the F606W filter drawn from a target
list of 143 clusters.

ACS/WFC 10886

The Sloan Lens ACS Survey: Towards 100 New Strong Lenses

As a continuation of the highly successful Sloan Lens ACS {SLACS}
Survey for new strong gravitational lenses, we propose one orbit of
ACS-WFC F814W imaging for each of 50 high- probability strong
galaxy-galaxy lens candidates. These observations will confirm new
lens systems and permit immediate and accurate photometry, shape
measurement, and mass modeling of the lens galaxies. The lenses
delivered by the SLACS Survey all show extended source structure,
furnishing more constraints on the projected lens potential than
lensed-quasar image positions. In addition, SLACS lenses have lens
galaxies that are much brighter than their lensed sources,
facilitating detailed photometric and dynamical observation of the
former. When confirmed lenses from this proposal are combined with
lenses discovered by SLACS in Cycles 13 and 14, we expect the final
SLACS lens sample to number 80--100: an approximate doubling of the
number of known galaxy-scale strong gravitational lenses and an
order-of-magnitude increase in the number of optical Einstein rings.
By virtue of its homogeneous selection and sheer size, the SLACS
sample will allow an unprecedented exploration of the mass structure
of the early-type galaxy population as a function of all other
observable quantities. This new sample will be a valuable resource to
the astronomical community by enabling qualitatively new strong
lensing science, and as such we will waive all but a short {3-month}
proprietary period on the observations.

ACS/WFC/NIC3 10632

Searching for galaxies at z6.5 in the Hubble Ultra Deep Field

We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the
area of the original Hubble Ultra Deep Field NICMOS parallel fields
and - through simultaneous parallel observations - deep NICMOS {F110W,
F160W} imaging of the ACS UDF area. Matching the extreme imaging depth
in the optical and near-IR bands will result in seven fields with
sufficiently sensitive multiband data to detect the expected typical
galaxies at z=7 and 8. Presently no such a field exist. Our combined
optical and near-IR ultradeep fields will be in three areas separated
by about 20 comoving Mpc at z=7. This will allow us to give a first
assessment of the degree of cosmic variance. If reionization is a
process extending over a large redshift interval and the luminosity
function doesn't evolve strongly beyond z=6, these data will allow us
to identify of the order of a dozen galaxies at 6.5z8.5 - using the
Lyman break technique - and to place a first constrain on the
luminosity function at z6.5. Conversely, finding fewer objects would
be an indication that the bulk of reionization is done by galaxies at
z=6. By spending 204 orbits of prime HST time we will capitalize on
the investment of 544 prime orbits already made on the Hubble Ultra
Deep Field {UDF}. We have verified that the program as proposed is
schedulable and that it will remain so even if forced to execute in
the 2-gyro mode. The data will be non-proprietary and the reduced
images will be made public within 2 months from the completion of the
observations.

FGS 10989

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric
elements {perturbation orbit semi-major axis and inclination} of
extra-solar planets orbiting six stars. These companions were
originally detected by radial velocity techniques. We have
demonstrated that FGS astrometry of even a short segment of reflex
motion, when combined with extensive radial velocity information, can
yield useful inclination information {McArthur et al. 2004}, allowing
us to determine companion masses. Extrasolar planet masses assist in
two ongoing research frontiers. First, they provide useful boundary
conditions for models of planetary formation and evolution of
planetary systems. Second, knowing that a star in fact has a plantary
mass companion, increases the value of that system to future
extrasolar planet observation missions such as SIM PlanetQuest, TPF,
and GAIA.

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 10744

WFPC2 Cycle 14 Decontaminations and Associated Observations

This proposal is for the WFPC2 decons. Also included are instrument
monitors tied to decons: photometric stability check, focus monitor,
pre- and post-decon internals {bias, intflats, kspots, & darks}, UV
throughput check, VISFLAT sweep, and internal UV flat check.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST:
17898-0 - Battery 4 Capacity Test Script & 5 Battery Pressure Limit
COP (Thru step 18)
17909-0 - Continuous Engineering Recording for Battery 4 BCT

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 11 11
FGS REacq 04 04
OBAD with Maneuver 30 30

SIGNIFICANT EVENTS:

Battery 4 Capacity Test Flash Report # 3

Final Bat 4 capacity result for 2006: 57.5Ah @ 5A (53.5Ah @ 9A).
Compare to 2004: 55.7Ah @ 5A (51.7 @ 9A).