Status Report

NASA Hubble Space Telescope Daily Report #3863

By SpaceRef Editor
May 20, 2005
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT       # 3863



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.


ACS CCDs daily monitor – Cycle 13 – Part 2

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.

ACS/WFC 10119

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

Seven 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
forthcoming Swift satellite will report few-arcsecond localizations
for short-hard bursts in minutes, however, 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 the
short-hard bursts are 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
their observations.

ACS/WFC 10152

A Snapshot Survey of a Complete Sample of X-ray Luminous Galaxy
Clusters from Redshift 0.3 to 0.7

We propose a public, uniform imaging survey of a well-studied,
complete, and homogeneous sample of X-ray clusters. The sample of 73
clusters spans the redshift range between 0.3-0.7. The samples spans
almost 2 orders of magnitude of X-ray luminosity, where half of the
sample has X-ray luminosities greater than 10^44 erg/s {0.5-2.0 keV}.
These snapshots will be used to obtain a fair census of the the
morphology of cluster galaxies in the cores of 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 potentially an assessment of the
contribution of large scale structure to lensing shear.

ACS/WFC 10352

A Study of the Physics of Extended Relativistic X-ray Jets, Discovered
in our Chandra Survey

We will measure the changing flow speeds, magnetic fields, and energy
fluxes in well-resolved quasar jets found in our short-exposure
Chandra survey by combining new, deep Chandra data with radio and
optical imaging. We will image each jet with sufficient sensitivity to
estimate beaming factors and magnetic fields in several distinct
regions, and so map the variations in these parameters down the jets.
HST observations will help diagnose the role of synchrotron emission
in the overall SED, and may reveal condensations on scales less than
0.1 arcsec.

ACS/WFC 10417

Host Galaxies and Environments of the Most Massive Black Holes in the
Early Universe

The existence of luminous quasars with billion solar mass black holes
at high redshift poses important questions about the relation between
the formation and evolution of the earliest galaxies and quasars in
the universe: how could these high- redshift black holes accrete
matter so quickly and so efficiently? Is the quasar phase connected to
the formation of galactic bulge in the earliest epoch? Was the black
hole-bulge mass relation observed locally already established at
high-redshift? We will use ACS/WFC to obtain rest-frame UV imaging of
five quasars at z~4 with the highest estimated black hole mass, of the
order 10 billion solar masses. The goal of the HST observation is to
directly detect their host galaxies and to probe their galactic
environment. These quasars are likely among the most massive and
luminous host galaxies at high-redshift, providing ideal targets for
direct detection. The rest-frame UV properties measured with HST will
be combined with rest-frame optical, mid to far-IR oberservations of
these quasars to measure the star-formation rate, to estimate the
stellar age and mass of the host galaxy, and to probe the
quasar/starburst connection, quasar triggering mechanism and relation
between black hole and bulge formation at the highest possible
redshift. One of the targets, PSS 2322+1944 {z=4.17}, is a
gravitational lensed quasar with a nearly complete Einstein ring in CO
emission, providing a unique opportunity to study the small scale
structure of a high-redshift quasar host galaxy.

ACS/WFC 10427

A Deep Search for Companions in the Pluto-Charon System

We propose to perform a deep search for new satellites in the
Pluto-Charon system using the ACS in WFC mode. In a single orbit,
ACS/WFC imaging will reach a sensitivity that is ~5.5 mag fainter than
previous surveys, and we will be able to detect objects that are only
~5 km in diameter, if they have the same albedo as Pluto {50%}, and
~17 km if the albedo is similar to that of cometary nuclei {4%}. The
discovery of a satellite in the Pluto-Charon system would be an
exciting development in the burgeoning field of satellite formation
theory and would also provide critical mission support for the New
Horizons mission, which will be launched in January 2006 and will make
a close flyby of Pluto-Charon as early as July 2015. Pluto is
approaching the Milky Way, and observations near the time of this
year’s opposition will mitigate the background confusion problem,
which generally becomes worse during the coming decade. The high
spatial resolution of HST is ideal for this type of search in crowded
stellar fields, and the field-of-view of the ACS/WFC is almost
perfectly matched to the orbital stability radius of companions in the
Pluto-Charon system. One additional image, taken ~5 days after the
first, is needed to confirm that any detected objects are truly
members of the Pluto-Charon system. Thus, the entire program requires
a total of only 2 orbits.


The COSMOS 2-Degree ACS Survey

We will undertake a 2 square degree imaging survey {Cosmic Evolution
Survey — COSMOS} with ACS in the I {F814W} band of the VIMOS
equatorial field. This wide field survey is essential to understand
the interplay between Large Scale Structure {LSS} evolution and the
formation of galaxies, dark matter and AGNs and is the one region of
parameter space completely unexplored at present by HST. The
equatorial field was selected for its accessibility to all
ground-based telescopes and low IR background and because it will
eventually contain ~100, 000 galaxy spectra from the VLT-VIMOS
instrument. The imaging will detect over 2 million objects with I> 27
mag {AB, 10 sigma}, over 35, 000 Lyman Break Galaxies {LBGs} and
extremely red galaxies out to z ~ 5. COSMOS is the only HST project
specifically designed to probe the formation and evolution of
structures ranging from galaxies up to Coma-size clusters in the epoch
of peak galaxy, AGN, star and cluster formation {z ~0.5 to 3}. The
size of the largest structures necessitate the 2 degree field. Our
team is committed to the assembly of several public ancillary datasets
including the optical spectra, deep XMM and VLA imaging, ground-based
optical/IR imaging, UV imaging from GALEX and IR data from SIRTF.
Combining the full-spectrum multiwavelength imaging and spectroscopic
coverage with ACS sub-kpc resolution, COSMOS will be Hubble’s ultimate
legacy for understanding the evolution of both the visible and dark


The Formation and Evolution of Spirals: An ACS and WFPC2 Imaging
Survey of Nearby Galaxies

Over 50% of galaxies in the local universe are spirals. Yet the star
formation histories and evolution of this crucial population remain
poorly understood. We propose to combine archival data with new
ACS/WFC and WFPC2 observations of 11 galaxies, to tackle a
comprehensive investigation of nearby spirals covering the entire
spiral sequence. The new observations will fill a serious deficiency
in HST’s legacy, and maximize the scientific return of existing HST
data. The filter combination of UBVI, and Halpha is ideal for studying
stellar populations, dust properties, and the ISM. Our immediate
scientific objectives are: {i} to use the resolved cluster
populations, both young massive clusters and ancient globular clusters
as a chronometer, to understand how spirals assembled as a function of
time; {ii} study the rapid disruption properties of young clusters;
and {iii} understand dust distributions in spirals from pc to kpc
scales. Each of these goals provides an important step towards
charting the evolution of galaxies, and an essential baseline for
interpreting the galaxy populations being surveyed in both the early
and present universe. The resolution of our survey, which exploits the
excellent imaging capabilities of HST’s two optical cameras, will
enable us to understand the record of star cluster, and galaxy
formation in a level of detail which is not possible for more distant
systems. Finally, the proposed observations will provide a key to
interpret an extensive, multiwavelength archive of space- and ground-
based data at lower spatial resolution {SPITZER, CHANDRA, GALEX,
NICMOS P alpha and H band imaging} for local spirals.

NIC3 10702

The COSMOS 2-Degree ACS Survey NICMOS Parallels

The COSMOS 2-Degree ACS Survey NICMOS Parallels. This program is a
companion to program 10092.


NICMOS Post-SAA calibration – CR Persistence Part 1.

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.


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


9819 – GSAcq(1,2,1) returns to SSM control @129/1941z OTA SE review of
PTAS processing reveals that GSAcq(1,2,1) at 129/19:40:51, achieved
FL-DV on both FGS 1 and 2 by 19:45:31, but both FGSs returned to SSM
control at 19:47:14. Both FGSs successfully recovered to FL-DV at

9820 – ReAcq(1,2,2) requires multiple entries into Course Track
@130/2029z OTA SE review of PTAS processing revealed that ReAcq(1,2,2)  
at 130/20:28:50 required three entries into Coarse Track on FGS1
before achieving CT-DV.

9821 – ReAcq(1,2,2) requires two attempts to achieve FL-DV @130/2251z
OTA SE review of PTAS processing reveals that ReAcq(1,2,2) at
130/21:50:39 required two attempts to achieve FL-DV on FGS1 due to
scan step limit exceeded. ReAcq was successful. This is the same star
set as HSTAR 9820.

9822 – ReAcq(1,2,2) requires two attempts to achieve FL-DV @131/1038z
OTA SE review of PTAS processing reveals that ReAcq(1,2,2) at
131/10:38:17 required two attempts to achieve FL-DV on FGS1 due to
scan step limit exceeded. ReAcq was successful.

9823 – GSAcq(1,2,2) requires multiple entries into Course Track
@134/2021z OTA SE review of PTAS processing revealed that GSAcq(1,2,2)  
at 134/20:21:09 required seven entries into Coarse Track on FGS1
before achieving CT-DV.



                           SCHEDULED     SUCCESSFUL    FAILURE TIMES 
 FGS Gsacq                11                      11 
 FGS Reacq                 5                        5 
 FHST Update              18                      18 


SpaceRef staff editor.