Daily 3867

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3867

PERIOD COVERED: DOY 144

OBSERVATIONS SCHEDULED

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/HRC 10377

ACS Earth Flats

High signal 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 used by the pipeline and will provide
a comparison with flats derived via other techniques: L-flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronagraphic
monitoring is required to assess the changing position of the spots.

ACS/HRC/WFPC2 9827

UV extinction by dust in unexplored LMC environments

The ensemble of results from studies of the UV extinction in the Milky
Way, Magellanic Clouds {MC}, M31 and M33, indicates a complex
dependence of the dust properties with environment, where starburst
activity and metallicity are relevant factors. Work in the LMC to
date, based on IUE data, has several drawbacks: a} only supergiants
could be used, b} they all have moderate extinction, c} the IUE S/N is
limited, d} the large IUE slit may include light from other sources,
such as scattered light from dust or faint companion stars, e} studies
are confined to few {extreme} environments. We propose to obtain UV
extinction curves more accurate than previous ones, sampling four
environments in the LMC with different levels of star formation
activity, including the general field, hitherto unexplored. The
results will characterize the properties of dust in different
conditions, at the LMC metallicity, which is useful to interpret
integrated properties of distant galaxies, as well as GALEX upcoming
UV surveys. A complementary study is under way with FUSE in the far-UV
range. The combined results will provide insight on the properties of
small grains.

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/WFPC2 10402

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 a {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 10150

NICMOS observations of A1689

The potential of galaxy clusters as ``cosmic telescopes'' has been
known for a long time, but practical results in the pre-ACS era have
been scarce due to two main problems: the uncertainty in determining
the magnification distribution of the cluster {the ``optics'' of the
instrument} and the presence of numerous bright cluster galaxies which
cover the field of view and hinder the detection of background
galaxies. We have developed techniques to solve these two problems
working with our ACS observations of A1689, the most powerful lens in
the sky, and for the first time we have been able to determine the
"specifications" of a cosmic telescope with a useful level of
precision, thanks to the detection and identification of more than 100
multiple images with reliable redshift information. We propose to
observe the high magnification region in the A1689 field in the F110W
band with a 3x3 mosaic of NIC3 pointings; the resulting image will
reach a lens-corrected limiting magnitudes of 29.5 for point sources,
surpassing in depth the UDF NICMOS observations and providing an
unique dataset with multiple scientific returns.

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: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 11 11
FGS Reacq 05 05
FHST Update 17 17
LOSS of LOCK

SIGNIFICANT EVENTS: (None)