NASA Hubble Space Telescope Daily Report # 3426

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3426

PERIOD COVERED: DOY 225

OBSERVATIONS SCHEDULED

WFPC2 9458

Probing the Formation & Evolution of M31’s Outer Disk and Halo

The fossil record of galaxy formation and evolution is imprinted on the
spatial
distribution, ages and metallicities of galactic stellar populations. The
observations proposed here build significantly upon our extensive
ground-based
and archival WFPC2 programs and aim to constrain the formation and evolution
of
our nearest large neighbor, M31. We propose deep imaging of 8 fields in the
outer disk and halo, several of which have been identified from our
panoramic
ground-based CCD survey {covering ~ 26 square degrees} to possess
significant
stellar density and/or potential metallicity variations. Deep
colour-magnitude
diagrams reaching ~2-3 magnitudes below the horizontal branch will be
constructed, allowing detailed characterization of the luminous evolved
stellar
populations via the red giant metallicity distribution, the luminous
asymptotic
giant branch, the horizontal branch morphology and the red clump, as well
as the
detection of a main-sequence that may be present from any younger
component. Our
primary goals are to: {i} quantify the stellar population variations
associated
with M31 halo substructure, including the newly- discovered giant stellar
stream, and {ii} derive stringent constraints on the age and metallicity of
stars in the far outer disk. These observations will directly address two
key
predictions of cold dark matter hierarchical galaxy formation models.

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 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 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 9658

ACS Earth Flats

This program will obtain sequences of flat field images by observing the
bright
Earth. Several UV filters from the interim calibration program {9564}
require
additional exposures to obtain the required illumination. A few UV filters
from
this program will be repeated to monitor for changes in the flat fields and
to
verify the interim results. Since no streaks are observed in the UV, the
wavelength coverage is extended to longer wavelengths in order to explore
the
severity of streaks in the flats from clouds in the FOV. We have added
exposures
for the HRC in the visible filters to verify the results derived from the
L-flat
campaign and to explore the severity of streaks. We have also added
exposures on
WFC using the minimum exposure time and using filters which will not
saturate
the brightest WFC pixel by more than 10 times the full well.

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.

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.

STIS/CCD/MA1 9784

The rarest of sightlines: probing the metallicity of a DLA with a nearby Low
Surface Brightness galaxy

We seek to measure the gas-phase metallicity, dust content, and gas
kinematics
in the interstellar medium {ISM} of the Low Surface Brightness {LSB} galaxy
SBS
1543+593, by observing absorption lines in the spectrum of the background
QSO HS
1543+5921. The QSO shines directly through the center of the LSB galaxy,
producing a damped Lyman-alpha {DLA} line. This is the lowest redshift DLA
system known outside of the local group. Specifically, we wish to use the
G140M
grating of STIS to: a} determine the metallicity of the interstellar gas in
the
LSB galaxy by accurately measuring the column densities of neutral hydrogen
and
sulphur; and b} estimate the amount of dust present from a precise measure
of
the nickel column density. The grating settings chosen to accomplish these
goals
will also allow us to: c} characterize the kinematics of cool gas in the
disk
and halo of the LSB galaxy by observing the line profiles of strong low
ionization species {Si II, O I, C I, C II, etc.}; and d} search for
absorption
from NV which may arise in any highly ionized component of the ISM due to
accretion of intragroup gas onto the galaxy.

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.

STIS 9855

Exploring Interstellar Krypton Abundance Variations at Kiloparsec Scales

We propose to obtain high-resolution STIS echelle observations of the
interstellar Kr I 1236 absorption toward eight stars situated in the
Galactic
disk beyond the Carina/Sagittarius or Perseus Arms. The measurement of
interstellar krypton abundances is a relatively simple way to investigate
elemental abundance variations in the Galaxy, since its dominant form is
neutral
and it is undepleted in the ISM. Furthermore, the intrinsic strengths of
krypton’s UV resonance lines combined with its low relative abundance to
hydrogen produce weak, unsaturated features in typical Galactic sight lines.
Previous GHRS and STIS measurements have demonstrated that Kr/H abundance
ratios
within the local spiral arm, the Orion Spur, are remarkably uniform;
however,
anomalously high krypton abundances have been measured for the only two
sight
lines extending also through gas outside the Orion Spur. This program is
designed to determine whether these sight lines are isolated cases of
enrichment, or if they are representative of large scale krypton abundance
variations outside the local arm. Since krypton is undepleted in the ISM,
these
observations will also be relevant to the study of total elemental
abundance and
depletion variations for a variety of elements with resonance lines between
1170
and 1372 Angstroms.

ACS/WFC 9891

A snapshot survey of rich stellar clusters in the Large and Small Magellanic
Clouds

Rich stellar clusters are vital to a wide variety of astrophysical research,
from stellar evolution studies to the formation and evolution of galaxies.
In
this context, it is important to understand how rich star clusters form and
evolve. The cluster systems in the LMC and SMC are particularly important in
achieving this, because they are the only systems which contain clusters at
all
stages of evolution while being close enough to be studied as fully resolved
stellar populations – although in general this requires the capabilities of
HST.
We have recently investigated the structural evolution of LMC and SMC
clusters
using archival WFPC2 data, and demonstrated a dramatic trend in the sizes of
these clusters with age. We have shown that this trend likely represents
genuine
structural evolution in these clusters, although it is not clear whether we
are
observing a dynamical process or the signature of changing formation
conditions.
This result has implications for all astronomical research involving massive
stellar clusters. To develop this work further requires the extension of
our two
samples, so that they are statistically quantifiable. This will allow a
number
of key questions regarding the structural evolution trend to be answered. We
propose a two-colour ACS/WFC SNAP survey of rich Magellanic Cloud clusters
to
achieve this aim. The unique resolution and sensitivity of ACS/WFC is
required
for success, because of the crowded nature of the targets. The SNAP data
will
have a large number of additional applications, both to globular cluster and
Magellanic Cloud research.

ACS 9984

Cosmic Shear With ACS Pure Parallels

Small distortions in the shapes of background galaxies by foreground mass
provide a powerful method of directly measuring the amount and distribution
of
dark matter. Several groups have recently detected this weak lensing by
large-scale structure, also called cosmic shear. The high resolution and
sensitivity of HST/ACS provide a unique opportunity to measure cosmic shear
accurately on small scales. Using 260 parallel orbits in Sloan textiti
{F775W}
we will measure for the first time: beginlistosetlength sep0cm
setlengthemsep0cm
setlength opsep0cm em the cosmic shear variance on scales <0.7 arcmin, em
the
skewness of the shear distribution, and em the magnification effect.
endlist Our
measurements will determine the amplitude of the mass power spectrum
sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20, and the mass density
Omega_m with s/n=4. They will be done at small angular scales where
non-linear
effects dominate the power spectrum, providing a test of the gravitational
instability paradigm for structure formation. Measurements on these scales
are
not possible from the ground, because of the systematic effects induced by
PSF
smearing from seeing. Having many independent lines of sight reduces the
uncertainty due to cosmic variance, making parallel observations ideal.

FLIGHT OPERATIONS SUMMARY:

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

COMPLETED OPS REQs: None

OPS NOTES EXECUTED: None

                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                7                          7
FGS REacq                7                          7
FHST Update              17                        17
LOSS of LOCK

SIGNIFICANT EVENTS

SMS SA223N02: This SMS recovers NICMOS from Safemode, monitors its dark
current (prop. 10064),
and runs the first part of the filter wheel test (prop. 10062). NICMOS in
Boot as of 226/0506z.

Partially completed CCS Release 5.0.3 D" String Exception and Compare
testing
224/14:00Z – 18:30Z using CCS D String with CCS Release 5.0.3 and SMPRD
S07200S and
CCS "B" String with CCS Release 4.0.3 and PRD S07200. Part 1 of the test
was completely
successful. CCS responded to erroneous logins as expected. Command
attempts without
privileges failed. The FTP of a file from Backbone to Core was
successful. Part 2 of
the test was completely successful. CCS handled command typos
correctly. Command Queue
and the Countdown Clock functionality were verified. SM/PART file transfer
will take
place at a later date due to SM/PART personnel unavailability. After
opening CCSLite,
it was found there were no user pages available. Part 3 of the test was
completed
successfully. CCS handled format changes, CRC errors, minor frame gaps,
and FEP mode
changes correctly. Commanding in various erroneous command modes were
handled
appropriately. During testing at 224/15:27:20Z, CCS experienced an
unexpected loss
of data. After HITT/SOC/CCS troubleshooting of the problem and an
investigation by
Sys Admin, it was determined Packet Filter 14 had an ethernet driver
failure. After
a switch to Packet Filter 15, data was ingested nominally. This test was
run in
parallel with the "B" String for comparison. Comparison was nominal. TSAR
2582
was written.