Daily Report #4162

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4162

PERIOD COVERED: UT July 24, 2006 (DOY 205)

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/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/WFC 10258

Tracing the Emergence of the Hubble Sequence Among the Most Luminous
and Massive Galaxies

There is mounting evidence that the redshift range 1 z 2 was an
important era when massive galaxies assembled their stellar content
and assumed their present--day morphologies. Despite extensive HST
imaging surveys, however, there is very little data in the optical
rest frame {i.e., observed near--infrared} on the morphologies of the
most luminous galaxies at these redshifts. We propose to image a
carefully selected set of 20 of the most luminous, K--band selected
GOODS galaxies at 1.3 z 2, using NICMOS camera 2. This offers
diffraction--limited, critically sampled imaging at 1.6 microns to
ensure the best angular resolution for comparison to ACS. The galaxies
are chosen to span a simple 4--fold parameter space of morphological
and spectral type, in order to provide the most information about the
variety of massive galaxy properties in this redshift range. We will
investigate the emergence of large scale--length disks, stable spiral
structure, mature bulges with red stellar populations, central bar
structures, the incidence of disturbed morphology, the existence {or
lack thereof} of blue ellipticals, and other questions that concern
the evolution and maturation of the brightest, largest, and most
massive ordinary galaxies in this critical redshift range.

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.

NIC1 10889

The Nature of the Halos and Thick Disks of Spiral Galaxies

We propose to resolve the extra-planar stellar populations of the
thick disks and halos of seven nearby, massive, edge-on galaxies using
ACS, NICMOS, and WFPC2 in parallel. These observations will provide
accurate star counts and color-magnitude diagrams 1.5 magnitudes below
the tip of the Red Giant Branch sampled along the two principal axes
and one intermediate axis of each galaxy. We will measure the
metallicity distribution functions and stellar density profiles from
star counts down to very low average surface brightnesses, equivalent
to ~32 V-mag per square arcsec. These observations will provide the
definitive HST study of extra-planar stellar populations of spiral
galaxies. Our targets cover a range in galaxy mass, luminosity, and
morphology and as function of these galaxy properties we will provide:
- The first systematic study of the radial and isophotal shapes of the
diffuse stellar halos of spiral galaxies - The most detailed
comparative study to date of thick disk morphologies and stellar
populations - A comprehensive analysis of halo and thick disk
metallicity distributions as a function of galaxy type and position
within the galaxy. - A sensitive search for tidal streams - The first
opportunity to directly relate globular cluster systems to their field
stellar population We will use these fossil records of the galaxy
assembly process preserved in the old stellar populations to test halo
and thick disk formation models within the hierarchical galaxy
formation scheme. We will test LambdaCDM predictions on sub-galactic
scales, where it is difficult to test using CMB and galaxy redshift
surveys, and where it faces its most serious difficulties.

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 10847

Coronagraphic Polarimetry of HST-Resolved Debris Disks

We propose to take full advantage of the recently commissioned
coronagraphic polarimetry modes of ACS and NICMOS to obtain imaging
polarimetry of circumstellar debris disks that were imaged previously
by the HST coronagraphs, but without the polarizers. It is well
established that stars form in gas-rich protostellar disks, and that
the planets of our solar system formed from a circum-solar disk.
However, the connection between the circumstellar disks that we
observe around other stars and the processes of planet formation is
still very uncertain. Mid-IR spectral studies have suggested that disk
grains are growing in the environments of young stellar objects during
the putative planet- formation epoch. Furthermore, structures revealed
in well resolved images of circumstellar disks suggest gravitational
influences on the disks from co-orbital bodies of planetary mass.
Unfortunately, existing imaging data provides only rudimentary
information abou the disk grains and their environments. Our proposed
observations, which can be obtained only with HST, will enable us to
quantitatively determine the sizes of the grains and optical depths as
functions of their location within the disks {i.e., detailed
tomography}. Armed with these well-determine physical and geometrical
systemic parameters, we will develop a set of self-consistent models
of disk structures to investigate possible interactions between unseen
planets and the disks from which they formed. Our results will also
calibrate models of the thermal emission from these disks, that will
in turn enable us to infer the properties of other debris disks that
cannot be spatially resolved with current or planned instruments and
telescopes.

WFPC2 10608

Probing the star formation law in the extreme outer limits of M83, a
prototypical XUV-disk galaxy The Galaxy Evolution Explorer {GALEX} has
discovered a new sub-class of spiral galaxy, which we refer to as
extended UV-disk {XUV-disk} galaxies. They are distinguished by
conspicuous UV-bright star clusters located at galactocentric radii
extending to many times the optical {R25} extent, and appear to
represent a population of spiral galaxies still actively building, or
augmenting, their stellar disk. However, XUV-disks pose a mystery in
the form of a relative lack of HII regions {traced by H-alpha
emission} associated with outer disk, UV-bright stellar clusters. M83
is an XUV-disk prototype and the focus of this proposal. It has an
H-alpha surface brightness profile characterized by a steep decline at
the radius beyond which the gaseous disk is thought to become
dynamically stable {against collapse and ensuing star formation}, but
GALEX UV profiles show no "edge" at this location. Our HST study of
M83 aims to resolve this puzzling discrepancy, confirmed in several
XUV-disks, by searching for Lyman-continuum producing O stars that are
either absent or present without nebulosity. HST provides the only
means of resolving individual massive stars in the FUV band at M83's
distance. Without HST, we lose the critical ability to photometrically
classify O and B stars. Our multiwavelength observations will also
constrain the history of star formation in the outer disk over Gyr
timescales by characterizing the evolved stellar population, both
using resolved giants and color analysis of the diffuse background.

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: (None)

COMPLETED OPS REQUEST:
#17863-0 Place +CC SPA Back On-Line @ 205/18:54z

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 08 08
FGS REacq 08 08
OBAD with Maneuver 26 26

SIGNIFICANT EVENTS:

Flash Report: +CC SPA Back on-line

With suntime decreasing, battery temperatures are now at acceptable
levels and therefore the +CC SPA was placed back on-line at 205/1853
GMT in both hardware and in FSW. The +CC SPA will now be included in
HST's nominal charging scheme.