Status Report

NASA Hubble Space Telescope Daily Report #3420

By SpaceRef Editor
August 6, 2003
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HUBBLE SPACE TELESCOPE

DAILY REPORT # 3420

PERIOD COVERED: DOY 217

OBSERVATIONS SCHEDULED

NICMOS 8791

NICMOS Post-SAA calibration – CR Persistence Part 2

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.

STIS/FUV 9412

The Physical Parameters of the Hottest, Most Luminous Stars as a Function of
Metallicity

We have obtained excellent, new ground-based blue optical and HAlpha spectra
of
a sample of very early-type stars in the Magellanic Clouds in order to
measure
their physical properties, for comparison with the extensive data that
exists
for higher-metallicity Galactic stars. Our aim is to understand how
effective
temperatures depend upon metallicity {necessary in determining IMFs}, and to
explore the astrophysically interesting regime of stars of extreme
temperatures,
masses, and luminosities. In order to do this, we need to measure the
stellar
wind terminal velocities for our stars, necessary to constrain the stellar
models. These can only be measured with STIS/FUV on HST. In addition, we
will
obtain higher spatial resolution data on the HAlpha line for stars for which
nebular contamination is significant in our ground-based data. We also
include
several R136 stars with excellent STIS/CCD data but which lack UV line
measures.
These new HST data will provide important information about the strengths of
stellar winds at extreme luminosities and the calibration of the Wind
Momentum-
Luminosity Relationship at lower metallicities. This proposal was highly
rated
in Cycle 9, but only 4 snapshots were obtained. We have completed the
analysis
of these plus additional data from the archives, but need spectra of the
remaining objects if we are to answer the questions we pose.

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/CAL 9609

CCD Read Noise Monitor

This proposal measures the read noise of all the amplifiers {A, B, C, D} on
the
STIS CCD using pairs of bias frames. Full frame and binned observations are
made
in both Gain 1 and Gain 4, with binning factors of 1×1, 1×2, 2×1 and 2×2.
All
exposures are internals. Pairs of visits are scheduled for monthly
execution.

STIS 9612

STIS CCD Hot Pixel Annealing Cycle 11

The effectiveness of the CCD hot pixel annealing process is assessed by
measuring the dark current behavior before and after annealing and by
searching
for any window contamination effects. In addition CTE performance is
examined by
looking for traps in a low signal level flat. Follows on from proposal 8906.

STIS 9613

STIS CCD Spectroscopic Flats C11

Obtain CCD flats on the STIS CCD in spectroscopic mode.

STIS 9614

STIS CCD Imaging Flats C11

Investigate flat-field stability over a monthly period.

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.

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.

ACS/WFC/HRC 9771

The local Hubble flow and the density field within 6 Mpc

Great progress has been made recently in accurate distance measurements of
nearby galaxies beyond the Local Group based on the luminosity of the tip
of the
red giant branch {TRGB}. Over the last three years, snapshot surveys with
HST
have provided us with the TRGB distances for more than a hundred nearby
galaxies
obtained with an accuracy of about 10%. The local velocity field within 5
Mpc
exhibits a significant anisotropy which disagrees with a spherical
Virgo-centric
flow. The local Hubble flow is very cold, with 1-D rms deviations of ~30
km/s.
Cosmological simulations with Cold Dark Matter can only realize such low
dispersions with a combination of a low mean density of matter and a
substantial
component with negative pressure. There may be a constraint on the equation
of
state w=-p/rho. Our observations will concentrate on 116 galaxies whose
expected
distances lie within 4 – 6 Mpc, allowing us to trace a Dark Matter
distribution
in the Local Volume with twice the information currently available. The
program
is a good one for SNAP mode because the order and rate that the
observations are
made are not very important, as long as there is good completion over
several
years.

NIC2 9801

Are OH/IR Stars the Youngest post-AGB stars? A NICMOS Imaging Survey

Essentially all well-characterized preplanetary nebulae {PPNe}– objects in
transition between the AGB and planetary nebula evolutionary phases – are
bipolar, whereas the mass-loss envelopes of AGB stars are strikingly
spherical.
In order to understand the processes leading to bipolar mass-ejection, we
need
to know at what stage of stellar evolution does bipolarity in the mass-loss
first manifest itself. We have recently hypothesized that most OH/IR stars
{evolved mass- losing stars with OH maser emission} are very young PPNe. We
are
conducting a multiwavelength survey program of imaging and spectroscopic
observations of such objects, using a large, morphologically unbiased sample
selected using IRAS 12-to-25 micron colors. Our ongoing HST/SNAP imaging
survey
of the optically bright half of this sample with WFPC2 and ACS is highly
successful: 19/32 objects observed are extended with bipolar/multipolar
shapes
{remaining objects are unresolved}. Slightly more than 50% of our sample are
optically too faint or undetected but have strong near-IR counterparts — we
therefore propose a NICMOS SNAPshot imaging survey of these optically-faint
OH/IR stars. These observations are crucial for determining how and when the
bipolar geometry asserts itself. The results from our NICMOS survey
{together
with the WFPC2/ACS survey} will allow us to draw general conclusions about
the
onset of bipolar mass-ejection during late stellar evolution. Our
complementary
program of interferometric mapping of the OH maser emission in our sources
is
yielding kinematic information with spatial resolution comparable to that
in the
HST images. The HST/radio data will provide crucial input for theories of
post-AGB stellar evolution. In addition, these data will also indicate
whether
the multiple concentric rings, "searchlight beams”, and truncated
equatorial
disks recently discovered with HST in a few PPNe, are common or rare
phenomena.

ACS/WFC 9842

A Snapshot Search for Halo Very-Low-Mass Binaries

We propose a snapshot search for binary M subdwarf stars. These nearby stars
have high velocities and low metallicies that identify them as members of
the
old Galactic halo {Population II}. ACS imaging is requested to search for
secondary companions. This supplements a previous snapshot program that only
obtained 10 observations. The observed binary fraction will be compared to
the
disk M dwarf fraction to look for differences in star formation. It is
likely
that a system suitable for orbital mass determinations will be found. In
this
case, future HST observations could determine the first masses for
very-low-mass, low-metallicity stars.

WFPC2 9887

HST Observations of Astrophysically Important Visual Binaries

This is a continuation of a project begun in Cycle 7 and continued up
through
Cycle 11. The program consists of annual or biannual WFPC2 or FGS
observations
of three visual binary stars that will ultimately yield fundamental
astrophysical results, once their orbits and masses are determined. Our
targets
are the following: {1} Procyon {P = 41 yr}, for which our first WFPC2 images
yielded an extremely accurate angular separation of the bright F star and
its
much fainter white-dwarf companion. Combined with ground-based astrometry
of the
bright star, our observation significantly revised downward the derived
masses,
and brought Procyon A into excellent agreement with theoretical evolutionary
tracks for the first time. With the continued monitoring proposed here, we
will
obtain masses to an accuracy of better than 1%, providing a testbed for
theories
of both Sun-like stars and white dwarfs. {2} G 107-70, a close double white
dwarf {P = 19 yr} that promises to add two accurate masses to the tiny
handful
of white-dwarf masses that are directly known from dynamical measurements.
{3}
Mu Cas {P = 21 yr}, a famous metal-deficient G dwarf for which accurate
masses
will lead to the stars’ helium contents, with cosmological implications.

FGS 9971

FGS Astrometry of a Star Hosting an Extrasolar Planet: The Mass of Upsilon
Andromedae d

We propose observations with HST/FGS to determine the astrometric elements
{perturbation orbit semimajor axis and inclination} produced by the
outermost
extra-solar planet orbiting the F8V star Upsilon Andromedae. These
observations
will permit us to determine the actual mass of the planet by providing the
presently unknown sin i factor intrinsic to the radial velocity method which
discovered this object. An inclination, i = 30degrees, within the range of
one
very low precision determination using reanalyzed HIPPARCOS intermediate
data
products, would produce the observed radial velocity amplitude, K = 66 ms
with a
companion mass of ~8 M_Jupiter. Such a mass would induce in Upsilon
Andromedae a
perturbation semi-major axis, Alpha = 0arcs0012, easily within the reach of
HST/FGS fringe tracking astrometry. The proposed observations will yield a
planetary mass, rather than, as previous investigations have done, only
suggest
a planetary mass companion.

STIS/ACS/HRC 9975

Ozone, Condensates, and Dust in the Martian Atmosphere

We propose to utilize the unique UV capabilities of STIS and ACS/HRC in
order to
study the spatial and seasonal variations in ozone, condensates, and dust
in the
Martian atmosphere. The data obtained will be critical in addressing recent
breakthroughs in understanding the basic radiative, transport, and
microphysical
processes that provide for both long-term and short-term balance within the
global Mars climate system. The proposal includes both Cycle 11 & 12
observations in order to span the classic dust storm season on Mars and
provide
the first good opportunity for HST to observe a dusty atmosphere on the
planet.
The UV observations will complement visible and IR observations that will be
made during the Mars Global Surveyor Extended Mission and will provide
support
for the future UV observations of MARCI on the 2005 Mars Reconnaissance
Orbiter.

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:
0911-0 Limit Management During WFPC2 Decontamination (M001) @ 217/1128z

                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              12                       12
FGS REacq              06                        06
FHST Update            26                        26
LOSS of LOCK

SIGNIFICANT EVENTS:

Intercept SMS SA216N03_F1 received 217/1730z. First uplink completed
217/2020z

SpaceRef staff editor.