Status Report

NASA Hubble Space Telescope Daily Report # 3674

By SpaceRef Editor
August 17, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




NIC1/NIC2/NIC3 9993

Cycle 12 NICMOS dark current, shading profile, and read noise
monitoring program

The purpose of this proposal is to monitor the dark current, read
noise, and shading profile for all three NICMOS detectors throughout
the duration of Cycle 12. This proposal is an essentially unchanged
continuation of PID 9636 which cover the duration of Cycle 11.

WFPC2 9964

Dynamical Masses of White Dwarfs from Resolved Sirius-Like Binaries

In Cycle 8 we initiated a WFPC2 snapshot survey for resolved,
“Sirius-like” systems containing hot white-dwarf companions of
cooler main-sequence stars. Out of 17 systems observed to date, 8 have
been resolved with WFPC2 by using UV filters. Two of the resolved
systems—56 Persei and Zeta Cygni—have predicted or known orbital
periods short enough that dynamical masses can be determined for the
white dwarfs within reasonable times. These would thus add to the
extremely small number of white dwarfs presently having accurately and
directly measured masses. We propose to image them annually in the UV
with WFPC2. In addition, we will observe Zeta Cyg with FGS in order to
measure the absolute motion of the optical component, needed for the
mass solution. We also propose to observe Sirius itself with WFPC2
over the next 3 Cycles. The resulting astrometric data will not only
greatly improve the precision of the binary orbit and the dynamical
mass measurements for both the main-sequence and white-dwarf
components, but will also test definitively for the claimed presence
of a third body in this famous system.


Stellar Populations in the Outskirts of M33: A Unique Probe of Disk
Galaxy Formation

The fossil record of galaxy formation and evolution is imprinted on
the structure and composition of galactic stellar populations. We have
recently completed an extensive ground-based imaging survey of the low
mass Local Group spiral, M33. Our analysis of the global structure of
M33 suggests it is a ‘pure disk’ galaxy, with no discernible stellar
halo. Furthermore, the disk surface brightness declines very abruptly
beyond ~5 scalelengths. We propose here to obtain deep ACS imagery of
two fields in the far outer disk of M33, located at 4.5 and 6
exponential scalelengths. Deep colour-magnitude diagrams reaching main
sequence turn-offs of ~8 Gyr {corresponding to star formation episodes
since z< 1} will be constructed and used for quantitative modelling of
the star formation history. State-of-the-art cosmological simulations
of galaxy formation predict stars in the outer regions of galactic
disks should be predominantly young-to-intermediate age. The data we
propose to obtain will directly test this idea, and provide a
much-needed observational constraint on the epoch at which disk
galaxies were assembled. The proposed observations will provide an
excellent complement to an ongoing Cycle 11 program to study the outer
disk of the more massive system, M31.


Tracing the History of Cosmic Expansion to z~2 with Type Ia Supernovae

Type Ia supernovae {SNe Ia} provide the only direct evidence for an
accelerating universe, an extraordinary result that needs the most
rigorous test. The case for cosmic acceleration rests on the
observation that SNe Ia at z = 0.5 are about 0.25 mag fainter than
they would be in a universe without acceleration. A powerful and
straightforward way to assess the reliability of the SN Ia measurement
and the conceptual framework of its interpretation is to look for
cosmic deceleration at z > 1. This would be a clear signature of a
mixed dark-matter and dark-energy universe. Systematic errors in the
SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia
peak luminosity would not show this change of sign. We have obtained a
toehold on this putative “epoch of deceleration” with SN 1997ff at z
= 1.7, and 3 more at z > 1 from our Cycle 11 program, all found and
followed by HST. However, this is too important a test to rest on just
a few objects, anyone of which could be subject to a lensed
line-of-sight or misidentification. Here we propose to extend our
measurement with observations of twelve SNe Ia in the range 1.0 < z <
1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be
discovered as a byproduct from proposed Treasury and DD programs.
These objects will provide a much firmer foundation for a conclusion
that touches on important questions of fundamental physics.

ACS/WFC 9727

Exploration of the SN Ia Hubble Diagram at z > 1.2

In the spirit of a Treasury proposal, we propose to organize, and
deliver to the astronomical community, non-proprietary follow-up
observations of ~10 Type Ia supernovae at 1<z<1.7 that are expected to
be discovered in a Cycle 12 Treasury proposal. Together with the
currently available sample, this would provide a Hubble diagram with
over 20 SNe Ia in this redshift range, where it is possible to test
the current cosmological model in the epoch of deceleration: If z ~
0.5 SNe Ia are fainter due to evolution rather than an accelerating
expansion, they should continue to get fainter at even higher
redshifts. This size sample will show trends and outliers, and permit
a more rigorous treatment of the asymmetric amplification distribution
from gravitational lensing. This is a key redshift range for the
studies of dark energy that will be done with future surveys {and
future instruments now being designed}; this dataset will lay the
ground-work for these studies by establishing the simple properties of
the supernovae in this redshift range, including magnitudes, colors,
and timescales. If considered more appropriate, this proposal could be
treated as a part of a Treasury or Director’s Discretionary program,
since the data would be available to everybody immediately, and we
would welcome others who would want to work with us on it.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

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.


Accurately Mapping M31’s Microlensing Population

We propose to augment an existing microlensing survey of M31 with
source identifications provided by a modest amount of ACS {and WFPC2
parallel} observations to yield an accurate measurement of the masses
responsible for microlensing in M31, and presumably much of its dark
matter. The main benefit of these data is the determination of the
physical {or "Einstein"} timescale of each microlensing event, rather
than an effective {"FWHM"} timescale, allowing masses to be determined
more than twice as accurately as without HST data. The Einstein
timescale is the ratio of the lensing cross-sectional radius and
relative velocities. Velocities are known from kinematics, and the
cross-section is directly proportional to the {unknown} lensing mass.
We cannot easily measure these quantities without knowing the
amplification, hence the baseline magnitude, which requires the
resolution of HST to find the source star. This makes a crucial
difference because M31 lens mass determinations can be more accurate
than those towards the Magellanic Clouds through our Galaxy’s halo
{for the same number of microlensing events} due to the better
constrained geometry in the M31 microlensing situation. Furthermore,
our larger survey, just completed, should yield at least 100 M31
microlensing events, more than any Magellanic survey. A small amount
of ACS+WFPC2 imaging will deliver the potential of this large database
{about 350 nights}. For the whole survey {and a delta-function mass
distribution} the mass error should approach only about 15%, or about
6% error in slope for a power-law distribution. These results will
better allow us to pinpoint the lens halo fraction, and the shape of
the halo lens spatial distribution, and allow
generalization/comparison of the nature of halo dark matter in spiral
galaxies. In addition, we will be able to establish the baseline
magnitude for about 50, 000 variable stars, as well as measure an
unprecedentedly detailed color-magnitude diagram and luminosity
function over much of M31.

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

ACS/HRC 10255

A Never Before Explored Phase Space: Resolving Close White Dwarf / Red
Dwarf Binaries

We propose an ACS Snapshot imaging survey to resolve a well-defined
sample of highly probable white dwarf plus red dwarf close binaries.
These candidates were selected from a search for white dwarfs with
infrared excess from the 2MASS database. They represent unresolved
systems {separations less than approximately 2" in the 2MASS images}
and are distributed over the whole sky. Our HST+ACS observations will
be sensitive to a separation range {1-20 AU} never before probed by
any means. The proposed study will be the first empirical test of
binary star parameters in the post-AGB phase, and cannot be
accomplished from the ground. By resolving as few as 20 of our ~100
targets with HST, we will be able to characterize the distribution of
orbital semi-major axes and secondary star masses.


Globular Cluster Systems of Giant, Post-Starburst Shell Ellipticals

Mergers seem to have played a major role in determining the shapes and
dynamics of elliptical galaxies. A few galactic mergers still occur
and offer valuable clues to past evolutionary processes. Young
globular clusters formed during mergers hold strong promise for
age-dating such events, besides helping shed light on the
cluster-formation process itself. With young globulars in ongoing
mergers and ~0.5 Gyr old remnants now well studied {NGC 4038/39, 3256,
7252, and 3921}, we propose to observe 4 bona fide ellipticals
featuring ripples, tidal tails as well as post-starburst spectra {E+A
galaxies: strong Balmer absorption}, which are obvious candidates for
having undergone a dissipative merger 1-4 Gyr ago. If the globulars
formed during mergers are formed with a normal IMF, they should still
be around in large numbers in intermediate-age systems. If that is
indeed the case, it would constitute strong evidence in favor of the
scenario in which metal-rich globulars in ‘normal’ ellipticals are
formed in merging events. We plan to use these ACS observations to {1}
measure high-accuracy {g-I error of 0.1 mag} colors for clusters as
faint as the peak of the luminosity function {LF} of old globulars,
{2} use these colors to separate first- and second-generation
clusters, and {3} determine the LFs of the two kinds of clusters down
to 1.5 mag past the LF peak for old globulars. Deep dithered g&I-band
images form a crucial part of our observing strategy. When combined
with previous HST studies of globulars in mergers, this study will
yield about a dozen globular cluster systems with age estimates,
enough to make meaningful statements about the influence of mergers in
creating "red”, metal-rich globulars in giant E’s and the evolution
of the specific frequency of globular clusters during galactic

NIC/NIC3 10226

The NICMOS Grism Parallel Survey

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7<z<1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial–but poorly observed–redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

FGS 10202

Resolving OB Binaries in the Carina Nebula, Resuming the Survey

In March 2002 we carried out a small, high-angular resolution survey
of some of the brightest OB stars in the Carina Nebula with FGS1r in
an attempt to resolve binary systems which had thus far evaded
detection by other techniques. Of 23 stars observed, 5 new OB binaries
were discovered with component separations ranging from 0.015"
to0.325". This yield over the spatial domain of FGS1r’s angular
resolution, coupled with published statistics of the incidence of OB
stars in short-period spectroscopic, and long-period visual binaries
suggests that the fraction of binarity or multiplicity among OB stars
is near unity. Our unexpected resolution of the prototype O2 If* star
HD 93129A as a 55 milli-arcsecond double is a case in point that great
care must be exercised when one attempts to establish the IMF and
upper-mass cuttoff at the high-mass end of the HR diagram. We propose
to resume the survey to observe a larger, statistically meaningful
sample of OB stars to establish a firm assessment of multiplicity at
the high-mass end of the IMF in these clusters. We will also
investigate the single-star/binary-star status of several
astrophysically important, individual stars in order to enable a
better understanding of the evolution of high-mass stars.

ACS/HRC 10199

The Most Massive Galaxies in the Universe: Double Trouble?

We are proposing an HST snapshot survey of 70 objects with velocity
dispersion larger than 350 km/s, selected from the Sloan Digital Sky
Survey. Potentially this sample contains the most massive galaxies in
the Universe. Some of these objects may be superpositions; HST imaging
is the key to determining if they are single and massive or if they
are two objects in projection. The objects which HST imaging shows to
be single objects are interesting because they potentially harbor the
most massive black holes, and because their existence places strong
constraints on galaxy formation models. When combined with ground
based data already in hand, the objects which HST imaging shows are
superpositions provide valuable information about interaction rates of
early-type galaxies as well as their dust content. They also constrain
the allowed parameter space for models of binary gravitational lenses
{such models are currently invoked to explain discrepancies in the
distribution of lensed image flux ratios and separations}.

ACS/HRC 10198

Probing the Dynamics of the Galactic Bar through the Kinematics of
Microlensed Stars

The observed optical depths to microlensing of stars in the Galactic
bulge are difficult to reconcile with our present understanding of
Galactic dynamics. The main source of uncertainty in those comparisons
is now shifting from microlensing measurements to the dynamical models
of the Galactic bar. We propose to constrain the Galactic bar models
with proper motion observations of Bulge stars that underwent
microlensing by determining both the kinematic identity of the
microlensed sources and the importance of streaming motions. The
lensed stars are typically farther than randomly selected stars.
Therefore, our proper motion determinations for 36 targeted MACHO
events will provide valuable constraints on the dynamics of bulge
stars as a function of distance. The first epoch data for our proposed
events is already available in the HST archive so the project can be
completed within a single HST cycle. The exceptional spatial
resolution of HST is essential for completion of the project.
Constraints on the total mass in the bulge will ultimately lead to the
determination of the amount of dark matter in inner Galaxy.

FGS 10197

The Astrophysical Parameters of Very Metal-Poor Halo Binaries

Little is currently known concerning the mass-luminosity relation
{MLR} of Population II stars. In Cycle 10, we began an initial study
with FGS1 to resolve a sample of known spectroscopic binaries
preselected as high-velocity and/or low metallicity objects. This has
resulted in significant new information about the astrophysical
parameters of metal-poor stars, but was limited mainly to intermediate
metallicities, not to true Population II stars. A new sample of
metal-poor spectroscopic binaries identified by Latham and his
collaborators {e.g. Latham et al 2002} contains three new very
metal-poor objects resolvable with FGS. We propose to observe these
binaries and obtain additional observations of two very important
resolved targets from our initial sample. As with that program, we
will couple the already-known spectroscopic orbits with astrometric
information which only FGS can deliver at present. To ensure that the
most will be gained from these data, we also request observations of
three metal-poor single stars to be used as calibration objects. In
combination with results from our previous program, these observations
can be expected to resolve the question of the location of the
Population II main sequence and give valuable insight into the
accuracy of isochrone fitting for determination of globular clusters
ages. Due to the combination of target magnitudes and expected
separations, no object in this sample can be resolved without the
unique capabilities of FGS.

NIC2 10177

Solar Systems In Formation: A NICMOS Coronagraphic Survey of
Protoplanetary and Debris Disks

Until recently, despite decades of concerted effort applied to
understanding the formation processes that gave birth to our solar
system, the detailed morphology of circumstellar material that must
eventually form planets has been virtually impossible to discern. The
advent of high contrast, coronagraphic imaging as implemented with the
instruments aboard HST has dramatically enhanced our understanding of
natal planetary system formation. Even so, only a handful of evolved
disks {~ 1 Myr and older} have been imaged and spatially resolved in
light scattered from their constituent grains. To elucidate the
physical processes and properties in potentially planet-forming
circumstellar disks, and to understand the nature and evolution of
their grains, a larger spatially resolved and photometrically reliable
sample of such systems must be observed. Thus, we propose a highly
sensitive circumstellar disk imaging survey of a well-defined and
carefully selected sample of YSOs {1-10 Myr T Tau and HAeBe stars} and
{> app 10 Myr} main sequence stars, to probe the posited epoch of
planetary system formation, and to provide this critically needed
imagery. Our resolved images will shed light on the spatial
distributions of the dust in these thermally emissive disks. In
combination with their long wavelength SEDs the physical properties of
the grains will be discerned, or constrained by our photometrically
accurate surface brightness sensitivity limits for faint disks which
elude detection. Our sample builds on the success of the exploratory
GTO 7233 program, using two-roll per orbit PSF-subtracted NICMOS
coronagraphy to provide the highest detection sensitivity to the
smallest disks around bright stars which can be imaged with HST. Our
sample will discriminate between proposed evolutionary scenarios while
providing a legacy of cataloged morphologies for interpreting mid- and
far-IR SEDs that the recently launched Spitzer Space Telescope will

NIC2 10173

Infrared Snapshots of 3CR Radio Galaxies

Radio galaxies are an important class of extragalactic objects: they
are one of the most energetic astrophysical phenomena and they provide
an exceptional probe of the evolving Universe, lying typically in high
density regions but well-represented across a wide redshift range. In
earlier Cycles we carried out extensive HST observations of the 3CR
sources in order to acquire a complete and quantitative inventory of
the structure, contents and evolution of these important objects.
Amongst the results, we discovered new optical jets, dust lanes,
face-on disks with optical jets, and revealed point-like nuclei whose
properties support FR-I/BL Lac unified schemes. Here, we propose to
obtain NICMOS infrared images of 3CR sources with z<0.3 as a major
enhancement to an already superb dataset. We aim to deshroud dusty
galaxies, study the underlying host galaxy free from the distorting
effects of dust, locate hidden regions of star formation and establish
the physical characteristics of the dust itself. We will measure
frequency and spectral energy distributions of point-like nuclei,
expected to be stronger and more prevalent in the IR, seek spectral
turnovers in known synchrotron jets and find new jets. We will
strongly test unified AGN schemes and merge these data with existing
X-ray to radio observations. The resulting database will be an
incredibly valuable resource to the astronomical community for years
to come.

ACS/WFC 10146

Solving the problem of the White Dwarf Cooling Sequence End in M4: an
efficent approach

The end of the white dwarf {WD} cooling sequence {WDCS} has never been
observed, despite the importance that it has in providing an age
estimate of old stellar systems, independent from the standard method
of the main sequence turn off. The best targets for this investigation
are the closest stellar clusters, and, among them, globular clusters
are the most interesting ones. Being the oldest stellar aggregates,
they allow to probe the advanced WD cooling phases, and the
independent age estimate coming from the end of their WDCS has an
important cosmological impact. M4 is the best target for this
investigation. Despite huge observational efforts, we still miss the
end of its WDCS. The ACS camera offers a unique opportunity to
identify it. Coupled with already existing observations, we can
finally reach it with only 10 HST orbits. The data we are requesting
here, will also be used to complete other two programs of great
astrophysical impact: the observational detection of the main sequence
hydrogen burning limit, and the measurement of the geometrical
distance of M4.

ACS/HRC 10137

Cluster Archeology: The Origin of Ultra-compact Dwarf Galaxies

Ultra-compact dwarf {UCD} galaxies are a new type of galaxy we have
discovered in the central regions of the Fornax and Virgo galaxy
clusters. Our most recent observations in the Fornax Cluster show that
UCDs outnumber normal galaxies in the center of that cluster. Here we
propose snapshot imaging of UCDs in the Fornax and Virgo clusters to
test theories of how these fascinating objects formed. In particular
we wish to image Virgo cluster UCDs for which we have ground-based
Keck spectroscopy to test predictions that they formed more recently
than the Fornax UCDs.

ACS/HRC 10130

Systemic Proper Motions of the Magellanic Clouds from Astrometry with
ACS: II. Second Epoch Images

We request second epoch observations with ACS of Magellanic Cloud
fields centered on the 40 quasars in the LMC and SMC for which we have
first epoch Cycle 11 data. The new data will determine the systemic
proper motion of the Clouds. An extensive astrometric analysis of the
first epoch data shows that follow-up observations with a two year
baseline will allow us to measure the proper motion of the clouds to
within 0.022 mas/year in each of the two orthogonal directions
{assuming that we can image 25 quasars, i.e., with a realistic
Snapshot Program completion rate}. The best weighted combination of
all previous measurements has a seven times larger error than what we
expect. We will determine the proper motion of the clouds with 2%
accuracy. When combined with HI data for the Magellanic Stream this
will constrain both the mass distribution in the Galactic Halo and
theoretical models for the origin of the Magellanic Stream. Previous
measurements are too crude for such constraints. Our data will provide
by far the most accurate proper motion measurement for any Milky Way

FGS 10110

Parallaxes of Extreme Halo Subgiants: Calibrating Globular Cluster
Distances and the Ages of the Oldest Stars

The ages of the oldest stars are a key constraint on the evolution of
our Galaxy, the history of star formation, and cosmological models.
These ages are usually determined from globular clusters. However, it
is alternatively possible to determine ages of extreme Population II
subgiants in the solar neighborhood based on trigonometric parallaxes,
without any recourse to clusters. This approach completely avoids the
vexing issues of cluster distances, reddenings, and chemical
compositions. There are 3 known nearby, extremely metal-deficient Pop
II subgiants with Hipparcos parallax errors of 6-11% which are
available for such age determinations. At present, based on the latest
isochrones, the derived ages of these stars {HD 84937, HD 132475, and
HD 140283} are all close to 14 Gyr, uncomfortably close to or higher
than current estimates of the age of the universe. However, the errors
in the Hipparcos parallaxes imply uncertainties of at least 2 Gyr in
the ages of the 3 stars. We propose to measure parallaxes of these
three Pop II subgiants using HST’s Fine Guidance Sensor 1R. We expect
to reduce the Hipparcos parallax error bars by factors of 5-6,
providing the most stringent test yet of current theoretical stellar
models of Pop II stars and pushing the age uncertainties to below 0.5
Gyr. These data will also provide a major new constraint on the
distance scale of globular clusters, with wide implications for
stellar evolution and the calibration of Pop II standard candles.

ACS/WFC 10098

Probing the nature of Type Ia SNe through HST astrometry

Type Ia supernovae are of key importance in cosmology. Empirical
relations allow their use as cosmological standard candles. The
generally accepted picture is that the exploding star is a C+O white
dwarf which accretes matter from a companion in a binary system.
However, the nature of the companion is still unknown. It could either
be another WD, or be a giant, subgiant, or main-sequence star.
Calculations have shown that it is possible to distinguish among those
possibilities by the effect that the supernova explosion has on the
companion star. We propose to identify the companion star of the two
historical well-known SNeIa through ACS imaging of the targets
complemented by WFPC2 observations. A radial-velocity study of the
stars in those two Galactic SNeIa has been done from ground-based
facilities. To obtain the full motion vector of those stars, we plan
to use ACS for high-resolution astrometry in two different epochs.
That should allow to detect motion imparted during the explosion in
the direction perpendicular to the line of sight, down to a level of a
few milliarcsecs/yr.

WFPC2 10080

Wavelength Stability of Narrow Band and Linear Ramp Filters

Verify the mapping of wavelength as a function of CCD position on
LRFs; check for changes in central wavelengths of narrow band filters.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot


CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
development of hot pixels and test for any source of noise in ACS CCD
detectors. This programme will be executed once a day for the entire
lifetime of ACS.

ACS/WFC 10055

ACS Polarization Calibration

This proposal aims to address several specific issues for the
polarization calibration: {1} variations in calibration with position
on the detector {field dependence}, {2} dependence on telescope
roll-angle relative to the target, {3} orientation of the polarizer
axes, and {4} geometric distortion contributed by the polarizers.

ACS/WFC 10006

Black Hole X-ray Novae in M31

During A01-3 we found 22 Black Hole X-ray Novae {BHXN} in M31 using
Chandra, and with HST {WFPC2} found two optical counterparts. Our
results suggest either a surprisingly high ratio of BH to NS binaries,
or a surprisingly high duty cycle for BHXN. We propose to continue
this program, with the goals of understanding the relative number of
BH vs. NS X-ray binaries in the M31 bulge, and determining the orbital
period distribution and duty cycles of these BHXN. Continued
observations can determine the duty cycle. The new ACS will allow us
to go 2 mags deeper than the WFPC2, and could triple the number of
optical counterparts and therefore orbital period estimates. M31 is
the only galaxy near enough to allow this extragalactic survey for


Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.) None


  • 17245-2 Battery 1 Capacity Test ( Complete) @ 226/1433z)
  • 17251-0 GenSlew for Prop 10267 slot 14 @226/1458z
  • 17252-0 GenSlew for Prop 9987 slot 1 @226/1459z
  • 17253-0 GenSlew for Prop 9987 slot 2 @226/1501z
  • 17254-0 GenSlew for Prop 9987 slot 3 @226/1502z


FGS GSacq 31 31
FGS REacq 22 22
FHST Update 46 46


Completed Battery 1 Capacity Test @ 226/14:33Z (OR 17245-2). Battery 1
had sufficiently recovered from its discharge to 15 Volts, Voltage,
pressure, and loadshare were in family with the other batteries,
placed Battery 1 back online in FSW 6-battery system @ 226/14:25Z. The
new 6-battery BM SOC is 297 A-h. SOC 1 and SOC 2 safing test values
also required updating, modified SOC 1 to 225 A-h and SOC 2 to 170 A-h
for. Unmasked the K2 SPA Trim Relay and the proper optimization scheme
was reinstated. The EPS is now back in its nominal configuration. The
current integrated capacity for Battery 1, as measured through 5.1 Ohm
resistor, is 55.3 A-h. Battery 1 was last tested in September 2003 and
yielded a capacity of 60.7 A-h.

SpaceRef staff editor.