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Daily 3702



 
 
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Old September 24th 04, 08:56 PM
Dave
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Default Daily 3702

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3702

PERIOD COVERED: DOY 267

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 9733

Direct imaging of the progenitors of massive, core-collapse supernovae

Modern supernovae searches in the nearby Universe are discovering
large numbers of SNe which have massive star progenitors {Types II, Ib
and Ic}. The extensive HST {and ground-based} image archives of
galaxies within ~20Mpc enables their individual bright stellar content
to be resolved. As massive, evolved stars are the most luminous single
objects in a galaxy, the progenitors of core-collapse SNe should be
directly detectable on pre-explosion images. Within the last two
cycles we have set direct mass-limits on three type II-P supernovae
using HST images, and already these can be used to constrain
theoretical models of pre-supernova stellar evolution which predict
which stars cause which of the supernovae types. We request time to
continue this successful project, and require ACS observations of
future SNe which are discovered in galaxies closer than 20Mpc which
have pre-explosion HST archive images available. These ToO
observations will allow the SNe to be precisely positioned on the
pre-explosion frames with the required astrometric accuracy of around
0.05", and allow 3-colour photometry of the surrounding stellar
populations for reddening estimations. The goal of this project is to
directly identify the progenitor stars of core-collapse supernovae. We
will compare the progenitor detections or luminosity limits to our own
stellar evolutionary tracks in order to determine masses or
restrictive mass-limits for the progenitors.

ACS/HRC/WFC 10061

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 10166

ACS and WFPC2 Stellar Photometry in the Kepler Mission Target Field

We will observe three regions at the Galactic Equator {GE} to
determine the number of stars in the magnitude range from 18 to 25 in
the target field of the NASA Kepler mission. This mission will search
for Earth-size planets orbiting other stars. The field is a twelve by
twelve degree square in Cygnus. It abuts the GE. The detection
technique is to search photometrically for planetary transits. Faint
eclipsing binaries that are not spatially resolved from the target
star by Kepler may cause confusion, leading to false positive
detections. The HST is uniquely capable of determining the potential
magnitude of the issue in the region of the GE, where stellar
densities are extremely high.

ACS/WFC 10178

Imaging Polarimetry of Young Stellar Objects with ACS and NICMOS: A
study in dust grain evolution

The formation of planetary systems is intimately linked to the dust
population in circumstellar disks, thus understanding dust grain
evolution is essential to advancing our understanding of how planets
form. By combining {1} the high resolution polarimetric capabilities
of ACS and NICMOS, {2} powerful 3-D radiative transfer codes, and {3}
observations of objects known to span the earliest stellar
evolutionary phases, we will gain crucial insight into the initial
phases of dust grain growth: evolution away from an ISM distribution.
Fractional polarization is a strong function of wavelength, therefore
by comparing polarimetric images in the optical and infrared, we can
sensitively constrain not only the geometry and optical depth of the
scattering medium, but also the grain size distribution. By observing
objects representative of the earliest evolutionary sequence of YSOs,
we will be able to investigate how the dust population evolves in size
and distribution during the crucial transition from a disk+envelope
system to a disk+star system. The proposed study will help to
establish the fundamental time scales for the initial depletion of
ISM-like grains: the first step in understanding the transformation
from small submicron sized dust grains, to large millimeter sized
grains, and untimely to planetary bodies.

ACS/WFC 10207

Star Formation in Damped Lya Galaxies: Testing the Connection with the
Lyman Break Population

The principal challenge of damped Lya {DLA} research is to identify
and study the stellar components of these galaxies. Although two
decades of absorption-line research has yielded the HI gas content,
metallicity, velocity fields, molecular and dust content of these
galaxies only a handful have been studied in emission. Therefore, it
has been very difficult to compare the DLA galaxies with the
successful surveys of high z galaxies discovered in emission {e.g.
Lyman break galaxies; LBG}. This is particularly important given that
DLA systems are the probable precursors to galaxies like the Milky
Way. Because the DLA systems are identified toward bright background
quasars, deep observations at high spatial resolution with astable PSF
are essential and only HST provides the observing capability.
Recently, two major advances have greatly enhanced the prospects for
measuring emission from DLA host galaxies: {1} we have developed a new
spectroscopic technique for inferring the star formation rates {SFR}
of the DLA which enables one to pre-select the brightest candidates;
{2} the high spatial resolution and sensitivity of the ACS represents
a major improvement over previous capabilities. We will obtain deep
V-band images with the ACS of 5 high z DLA with the highest inferred
apparent optical magnitudes. The complete survey will offer a robust
statistical analysis of: {a} the extent and morphology of the DLA star
forming regions; {b} the likelihood that the DLA and LBG correspond to
the same population of protogalaxies; {c} a test of the protogalactic
clump models favored by CDM cosmology. We emphasize this program will
offer a major advance over all previous studies. Finally, we will
complement these HST observations with an extensive observing campaign
{IFU spectroscopy and deep IR imaging} on the Keck, VLT, and Magellan
telescopes to provide the most extensive dataset yet on the physical
properties of high z DLA.

ACS/WFC 10217

The ACS Fornax Cluster Survey

The two rich clusters nearest to the Milky Way, and the only large
collections of early-type galaxies within ~ 25 Mpc, are the Virgo and
Fornax Clusters. We propose to exploit the exceptional imaging
capabilities of the ACS/WFC to carry out the most comprehensive
imaging survey to date of early-type galaxies in Fornax: the ACS
Fornax Cluster Survey. Deep ACS/WFC images -- in the F475W {g'} and
F850LP {z'} bands -- will be acquired for 44 E, S0, dE, dE, N and dS0
cluster members. In Cycle 11, we initiated a similar program targeting
early-type galaxies in the Virgo Cluster {the ACS Virgo Cluster
Survey; GO-9401}. Our proposed survey of Fornax would yield an
extraordinary dataset which would complement that already in hand for
Virgo, and allow a definitive study of the role played by environment
in the structure, formation and evolution of early-type galaxies and
their globular cluster systems, nuclei, stellar populations, dust
content, nuclear morphologies and merger histories. It would also be a
community resource for years to come and, together with the ACS Virgo
Cluster Survey, constitute one of the lasting legacies of HST.

ACS/WFC 10342

Hubble Heritage Observations of NGC 1300

Observing NGC1300 in four bands for Hubble Heritage project.

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.

NIC2 10169

Star Formation in Luminous Infrared Galaxies: giant HII Regions and
Super Star Clusters

Luminous Infrared Galaxies {LIRGs, LIR = 10^11-10^12Lsol} and
Ultraluminous Infrared Galaxies {LIR10^12Lsol} account for
approximately 75% of all the galaxies detected in the mid-infrared in
the redshift range z=0-1.5. In the local universe it is found that
LIRGs are predominantly powered by intense star formation {SF}.
However, the physical conditions and processes governing such dramatic
activity over scales of tens to a few hundred parsecs are poorly
known. In the last decade HST has been playing a significant role,
mainly with the discovery of super star cluters {SSCs}, and more
recently, giant HII regions. Based on observations of a few LIRGs, we
found that these giant HII regions and associated SSCs appear to be
more common in LIRGs than in normal galaxies, and may dominate the
star formation activity in LIRGs. A larger sample is required to
address fundamental questions. We propose an HST/NICMOS targeted
campaign of a volume limited sample {v5200km/s} of 24 LIRGs. This
proposal will probe the role of giant HII regions in the overall
energetics of the current star formation, their relation to SSCs, and
the dependence of star formation properties on other parameters of
LIRGs. Such detailed knowledge of the SF properties of LIRGs in the
local universe is essential for understanding galaxies at high
redshift.

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
deliver.

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
pixels.

FLIGHT OPERATIONS SUMMARY:

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

Executed Ops Note 1271: Battery Pressure Limit Updates after 2004
Capacity Testing @ 267/22:10Z.

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 11 11
FGS REacq 5 5
FHST Update 15 15
LOSS of LOCK


SIGNIFICANT EVENTS: None



 




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