Daily 3891

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #3891

PERIOD COVERED: UT June 28, 2005 (DOY 179)

OBSERVATIONS SCHEDULED

ACS/HRC 10272

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for
supernovae {SNe}, most notably our Lick Observatory Supernova Search
{LOSS}, have found hundreds of SNe, many of them in quite nearby
galaxies {cz 4000 km/s}. Most of the objects were discovered before
maximum brightness, and have follow-up photometry and spectroscopy;
they include some of the best-studied SNe to date. We propose to
conduct a snapshot imaging survey of the sites of some of these nearby
objects, to obtain late-time photometry that {through the shape of the
light and color curves} will help reveal the origin of their lingering
energy. The images will also provide high- resolution information on
the local environment of SNe that are far superior to what we can
procure from the ground. For example, we will obtain color-color and
color-magnitude diagrams of stars in these SN sites, to determine
their progenitor masses and constraints on the reddening. Recovery of
the SNe in the new HST images will also allow us to actually pinpoint
their progenitor stars in cases where pre-explosion images exist in
the HST archive. Use of ACS rather than WFPC2 will make our snapshot
survey even more valuable than our Cycle 9 survey. This Proposal is
complementary to our Cycle 13 archival proposal, in which we outline a
plan for using existing HST images to glean information about SN
environments.

ACS/WFC 10120

The Formation Histories and Dynamical Roles of X-ray Binaries in
Globular Clusters

Close binaries are fundamental to the dynamical stability and
evolution of globular clusters, but large populations have been
extremely difficult to identify. Chandra X-ray images provide a
revolutionary resource, revealing a few to dozens of low-luminosity X-
ray sources in every cluster deeply examined; our own Chandra programs
uniformly study these ubiquitous X-ray sources {close binaries and
their progeny} in 11 clusters. However, definitive understanding of
the nature of the various X-ray subpopulations requires the
identification of optical counterparts, and HST is the demonstrated
key in these crowded environments. We thus propose a proven,
efficient, and uniform, HST multicolor imaging program for optical
identifications in 6 of our clusters with Chandra data on-hand, but
which lack adequate optical images in the HST archive. The proposed
ACS images will permit statistical classifications into the various
subtypes: CVs, qLMXBs, BY Dra's/RS CVn's {and MSPs}. A unique aspect
of our program is that our clusters span a range of physical
properties such as central concentration, cluster size, and
mass--essential ingredients in the formation, evolution, and dynamical
roles of cluster binaries. Exploiting this range of properties, we
have identified a relation that provides the first compelling link
between the number of X-ray sources and the predicted stellar
encounter frequency in globular cluster cores. But further progress in
understanding the details implicit in this relationship {e.g., whether
CVs and qLMXBs formed primarily via stellar encounters, while BY
Dra's/RS CVn's are mainly primordial binaries} demands uniform optical
identifications for multiple clusters, spanning the full range
physical properties.

ACS/WFC 10257

Astrometric and Photometric Study of NGC 6397 for Internal Motions,
Dark Binaries, and X-Ray Sources

We propose to observe the central regions of the globular cluster NGC
6397 with ACS/WFC once per month for the 10 months of its visibility
in Cycle 13. The project has three main goals: {1} Measure internal
motions for roughly 3000 stars within 150 arcseconds of the cluster
center, using archival WFPC2 as a first epoch. The motion of the
typical star will be measured to 10-20%. We will detect any central
black hole {BH} with a mass greater than 1000 solar masses, and will
also measure core-collapse signatures such as anisotropy. {2} Conduct
the first-ever search for heavy binaries by looking for the
astrometric "wobble" of the luminous secondary. We should find all
heavy binaries in the field with separations between 1 and 5 AU and
periods between 3 months and 5 years. {3} Search for opticall
counterparts to X-ray sources found by Chandra.

ACS/WFC 10421

Searching for Ancient Mergers in Early Type Host Galaxies of Classical
QSOs

Recent HST imaging of QSO host galaxies indicates that at least a
large fraction of QSOs reside in seemingly undisturbed elliptical
hosts. However, our deep Keck spectroscopy of a sample of these host
galaxies indicates that many of these objects were involved in a major
starburst episode between 0.6 and 1.6 Gyr ago. We propose to obtain
very deep ACS WFC observations of the five hosts in this sample that
have the most reliable age determinations to search for fine structure
indicative of a past merger event and to test the hypothesis that the
elliptical hosts are the products of relatively recent merger events
rather than old galaxies which formed at high redshifts. By
establishing a firm connection between ancient mergers and the aging
starbursts in these classical QSOs, we will be able to estimate the
fraction of the total QSO population that results directly from
mergers accompanied by massive starbursts and to place constraints on
the duty cycle for QSO activity.

ACS/WFC/WFPC2/NIC3 10395

Environmental drivers of galaxy evolution: an HST survey of dwarf
galaxy morphologies in the Abell

Galaxies in dense environments are subject to numerous physical
processes that leave a lasting impact, yet studies of galaxy evolution
to date have been limited to the most luminous galaxies -- those least
sensitive to environmental influence. We propose to explore the
environmental drivers of DWARF galaxy evolution: with a mosaic of 9x9
ACS pointings in F606W we will determine morphologies for ~1200
galaxies down to M_V=-14 in the A901/902 supercluster, spanning 3x3
Mpc at z=0.16. The deep ACS data will allow us to probe their surface
brightness profiles, shapes, sizes, asymmetry and fine structure such
as tidal features. With the addition of extensive existing multi-
wavelength data, we will probe the dependence of these important
parameters on dark matter content {from weak lensing maps}, the hot
intercluster medium {from deep XMM- Newton imaging}, and local galaxy
density {from hyper-accurate COMBO-17 photometric redshifts with delta
z=0.02 to m_R=24}, thus disentangling the various environmental
processes shaping dwarf galaxy evolution. Furthermore, the 8000+
background galaxies at 0.2z1.0 will be of enormous scientific
benefit for additional studies of weak lensing, AGN host galaxies, the
morphology-density relation, and the merger rate as a function of
redshift.

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration - CR Persistence Part 3

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.

NIC3/ACS/WFC 10404

The Nature of Protocluster Galaxies at z=2.16: Morphology-Density and
Color-Magnitude Relations

To establish the epoch when galaxy environment manifests itself as a
large-scale evolutionary process, we propose to extend the study of
galaxy colors and morphologies to a protocluster at z=2.16. Here the
universe is only 3 Gyrs old and significant differences are expected
between scenarios favoring a morphology-radius relation over a
morphology-density relation. In addition, because the fractional age
differences among cluster galaxies are larger, study of the
color-magnitude relation provides considerable leverage for
determining the epoch of early-type galaxy formation. To facilitate
direct comparison to studies at lower redshift, one must probe the
same rest-frame wavelengths with high photometric accuracy and at
similar physical scales. Its near- infrared photometric stability
{low, constant background} and ability to image large areas of sky at
high angular-resolution {compared to adaptive optics} makes HST/NICMOS
ideal for this program. Six pointings of NICMOS camera 3 will result
in rest-frame optical, high resolution images of 16 confirmed
protocluster members, and an additional 60 candidate protocluster
members including 29 EROs. These galaxies were selected with a variety
of techniques and span a range of projected radii within the
protocluster. The proposed observations constitute a unique
opportunity to extend the study of galaxies in overdense regions to an
early time in cosmic history.

WFPC2 10360

WFPC2 CYCLE 13 INTERNAL MONITOR

This calibration proposal is the Cycle 13 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
{gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a
monitor for possible buildup of contaminants on the CCD windows.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS

9867: GSacq(2,1,1) results in Fine Lock Backup (2,0,2) @
179/21:22:53z GSacq(2,1,1) scheduled at 179/21:19:21 - 21:26:38
resulted in fine lock backup (2,0,2) due to scan step limit exceeded
on fgs 1.


COMPLETED OPS REQUEST:
Operations Request #17457-0: Genslew for proposal 10425 - slot 4 @ 179/16:30z
Operations Request #17458-0: Genslew for proposal 10425 - slot 5 @ 179/16:32z


COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS Gsacq 10 10
FGS Reacq 05 05
FHST Update 15 15

SIGNIFICANT EVENTS: (None)