NASA Hubble Space Telescope Daily Report # 3421

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3421

PERIOD COVERED: DOY 218

OBSERVATIONS SCHEDULED

ACS/WFPC2 9488

Cosmic Shear – with ACS Pure Parallel Observations

The ACS, with greater sensitivity and sky coverage, will extend our ability
to
measure the weak gravitational lensing of galaxy images caused by the large
scale distribution of dark matter. We propose to use the ACS in pure
parallel
{non- proprietary} mode, following the guidelines of the ACS Default Pure
Parallel Program. Using the HST Medium Deep Survey WFPC2 database we have
measured cosmic shear at arc-min angular scales. The MDS image parameters,
in
particular the galaxy orientations and axis ratios, are such that any
residual
corrections due to errors in the PSF or jitter are much smaller than the
measured signal. This situation is in stark contrast with ground-based
observations. We have also developed a statistical analysis procedure to
derive
unbiased estimates of cosmic shear from a large number of fields, each of
which
has a very small number of galaxies. We have therefore set the stage for
measurements with the ACS at fainter apparent magnitudes and smaller, 10
arc-second scales corresponding to larger cosmological distances. We will
adapt
existing MDS WFPC2 maximum likelihood galaxy image analysis algorithms to
work
with the ACS. The analysis would also yield an online database similar to
that
in archive.stsci.edu/mds/

WFPC2 9589

WFPC2 Decontaminations and Associated Observations Pt. 1/3

This proposal is for the monthly WFPC2 decons. Also included are instrument
monitors tied to decons: photometric stability check, focus monitor, pre-
and
post-decon internals {bias, intflats, kspots, & darks}, UV throughput check,
VISFLAT sweep, and internal UV flat check.

WFPC2 9595

WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt3/3

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

STIS 9606

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS 9608

CCD Bias Monitor – Part 2

Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and
1×1
at gain = 4, to build up high-S/N superbiases and track the evolution of hot
columns.

STIS 9615

Cycle 11 MAMA Dark Monitor

This test performs the routine monitoring of the MAMA detector dark noise.
This
proposal will provide the primary means of checking on health of the MAMA
detectors systems through frequent monitoring of the background count rate.
The
purpose is to look for evidence of change in dark indicative of detector
problem
developing.

STIS 9633

STIS parallel archive proposal – Nearby Galaxies – Imaging and Spectroscopy

Using parallel opportunities with STIS which were not allocated by the TAC,
we
propose to obtain deep STIS imagery with both the Clear {50CCD} and
Long-Pass
{F28X50LP} filters in order to make color-magnitude diagrams and luminosity
functions for nearby galaxies. For local group galaxies, we also include
G750L
slitless spectroscopy to search for e.g., Carbon stars, late M giants and
S-type
stars. This survey will be useful to study the star formation histories,
chemical evolution, and distances to these galaxies. These data will be
placed
immediately into the Hubble Data Archive.

ACS 9675

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.

STIS 9708

STIS Pure Parallel Imaging Program: Cycle 11

This is the default archival pure parallel program for STIS during cycle 11.

WFPC2 9709

POMS Test Proposal: WFII parallel archive proposal

This is the generic target version of the WFPC2 Archival Pure Parallel
program.
The program will be used to take parallel images of random areas of the sky,
following the recommendations of the 2002 Parallels Working Group.

WFPC2 9710

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans.

ACS/HRC 9719

Metallicity Spreads in M31 Globular Clusters

Our recent deep HST photometry of the M31 halo globular cluster {GC}
Mayall~II,
also called G1, has revealed a red-giant branch with a clear spread that we
attribute to an intrinsic metallicity dispersion of at least 0.4 dex in
[Fe/H].
The only other GC exhibiting such a metallicity dispersion is Omega
Centauri,
the brightest and most massive Galactic GC, whose range in [Fe/H] is about
0.5
dex. These observations are obviously linked to the fact that both G1 and
Omega
Cen are bright and massive GC, with potential wells deep enough to keep part
of
their gas, which might have been recycled, producing a metallicity scatter
among
cluster stars. These observations dramatically challenge the notion of
chemical
homogeneity as a defining characteristic of GCs. It is critically important
to
find out how common this phenomenon is and how it can constrain
scenarios/models
of GC formation. The obvious targets are other bright and massive GCs, which
exist in M31 but not in our Galaxy where Omega Cen is an isolated giant. We
propose to acquire, with ACS/HRC, deep imaging of 3 of the brightest M31
GCs for
which we have observed velocity dispersion values similar to those observed
in
G1 and Omega Cen. A sample of GCs with chemical abundance dispersions will
provide essential information about their formation mechanism. This would
represent a major step for the studies of the origin and evolution of
stellar
populations.

STIS 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the integrated
light of galaxies and clusters. This program is using the low dispersion UV
and
optical gratings of STIS. The library will be roughly equally divided among
four
metallicities, very low {[Fe/H] lt -1.5}, low {[Fe/H] -1.5 to -0.5},
near-solar
{[Fe/H] -0.3 to 0.1}, and super-solar {[Fe/H] gt 0.2}, well-sampling the
entire
HR-diagram in each bin. Such a library will surpass all extant compilations
and
have lasting archival value, well into the Next Generation Space Telescope
era.
Because of the universal utility and community-broad nature of this venture,
we
waive the entire proprietary period.

STIS/CCD/MA1/MA2 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 {from STIS spectra of
main
sequence stars with higher reddening}, 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 intepret
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 9831

Multiplicity among brown dwarfs in the Pleiades cluster

We have compiled a sample of 32 confirmed brown dwarfs in the Pleiades
cluster.
We propose to observe this sample with HST/ACS in SNAPSHOT mode in order to
search for very low mass multiple systems. Our goals are: 1} to determine
the
occurrence and frequency of binary systems among substellar objects, which
hold
important clues to the formation and evolution mechanism{s} of ultracool and
brown dwarfs, 2} to get an estimate of the Initial Mass Function {IMF} at
very
low masses, which is still unknown and very much needed to be corrected for
binarity, 3} to compare the distribution of multiple systems in young open
clusters and in the field.

ACS/HRC 9853

A Search for Young Binary Brown Dwarfs: Constraining Formation Scenarios and
Masses Through Multiplicity

We propose to use the Advanced Camera for Surveys / High Resolution Camera
to
conduct a direct imaging multiplicity survey of 34 young brown dwarfs in the
nearest regions of recent star formation, the T association Taurus-Auriga
and
the OB association Upper Scorpius. The determined multiplicity fraction, the
separation distribution, and the mass ratio distribution will offer
stringent
observational constraints on proposed brown dwarf formation scenarios.
Moreover,
the small semi-major axes of known field and open cluster brown dwarf
binaries
suggest the exciting possibility of our identifying several very close
binaries
{< 15 AU}. Continued monitoring of these systems would yield, on a decade
timescale, the first dynamical mass estimates of T Tauri brown dwarfs. With
masses intermediate between those of stars and planets, brown dwarfs offer
our
best hope of relating the reasonably well understood processes of star
formation
to the less well understood processes of planet formation.

ACS/WFC 9872

Optical Counterpart of the Neutron Star 1E 1207.4-5209 in PKS 1209-51/52
Supernova Remnant

Chandra observations of the Compact Central Object 1E 1207.4-5209 in the PKS
1209-51/52 Supernova Remnant allowed us to discover the first absorption
lines
in the thermal spectrum of a neutron star and the 424 millisecond period of
this
object. This first discovery of spectral lines allows an opportunity to
measure
the gravitational redshift at the surface of a NS and constrain the Equation
of
State of the super-dense matter. The measured gravitational redshift depends
on
the correct identification of the spectral lines. Multiwavelength
observations
are needed to constrain the origin of the spectral lines. We propose deep
HST
imaging observations to search for the optical counterpart of this source
and
constrain the properties of this unique object.

ACS/WFC 9892

H-alpha Snapshots of Nearby Galaxies observed in F300W: Quantifying Star
Formation in a Dusty Universe

Previous studies of nearby galaxies show large discrepancies between
different
star formation {SF} indicators on large {>100 pc, or even global} scales:
the
strikingly complex interplay of young stars, dust and ionized gas are the
primary cause of this variance. The few galaxies in the HST Archive with
both
WFPC2 H-alpha and mid-UV {F255W or F300W} imaging show this complex geometry
extending down to <10 pc scales. We propose a SNAPshot survey in the ACS/WFC
H-alpha filter of 48 galaxies of all Hubble types, that are nearby but
beyond
the Local Group, and that were previously imaged with WFPC2 in the mid-UV
and in
F814W. We aim to provide a benchmark for understanding the SF processes in
both
normal and star-bursting galaxies, at spatial resolutions unattainable from
the
ground for a large and varied galaxy sample. These data can be applied to a
wide
range of astrophysical problems and will, therefore, be made public
immediately.
Our science goals are to: {1} spatially resolve the dust clouds and
filaments
which strongly affect mid-UV and H-alpha derived SF rates, {2} test how the
large-scale correlation between H-alpha and mid-UV flux breaks down on pc
scales, and {3} model the propagation of star formation by comparing the SF
over
time scales of ~100 Myr {via mid-UV} and ~5 Myr {via H-alpha}. This will {4}
significantly improve our insight into, and calibration of SF in UV-bright
galaxies at high z, and into the cosmic SF history.

FLIGHT OPERATIONS SUMMARY:

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

HSTAR 9108: GS Re-Acquisition (1,2,2) required 2 attempts to achieve FL
data on
FGS 2 @ 212/17:33Z. During the 1st FL attempt on
FGS 2, SSLE and Stop
flags came up during the FL walk down. Under
investigation.

COMPLETED OPS REQs:

• 17024-0 – Null genslew for proposal 8658 (slot 3) @ 218/1445z
• 17021-1 – MNCIINIV High Limits Adjustment @ 218/1705z
• 17022-0 – Configure History and Min/Max Buffer Collections Following 214 Circulator Anomaly @ 218/1722z
• 17025-0 – MNCICMDV Hight Limt Adjustment @ 218/2207z
• 17020-0 – Adjust NCS CPL Reservoir Setpoint @ 219/0000z

OPS NOTES EXECUTED: None

                        SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq            6                          6
FGS REacq            11                        11
FHST Update          12                        12
LOSS of LOCK

SIGNIFICANT EVENTS:

All Cooling System related commanding planned for DOY 218 has been
completed successfully. The commanding was performed in preparation for
the NCC Circulator and Compressor restart scheduled for 03/219 12:57.