Status Report

NASA Hubble Space Telescope Daily Report # 3524

By SpaceRef Editor
January 6, 2004
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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
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.


CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
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 9744

HST Imaging of Gravitational Lenses

Gravitational lenses offer unique opportunities to study cosmology, dark
galactic structure, galaxy evolution and quasar host galaxies. They are
also the
only sample of galaxies selected based on their mass rather than their
luminosity or surface brightness. While gravitational lenses can be discovered
with ground-based optical and radio observations, converting them into
astrophysical tools requires HST. HST has demonstrated that it is the only
telescope that can in each case precisely locate the lens galaxy, measure its
luminosity, color and structure, and search for lensed images of the source
galaxy given the typical image separations of ~1”. We will obtain ACS/WFC
V and
I images and NICMOS H images of 21 new lenses never observed by HST and
images of 16 lenses never observed by HST in the IR. As in previous cycles, we
request that the data be made public immediately.

ACS/WFC 9772

Galaxy Populations at Very Large Cluster Radii: The Outskirts of MS1054-03 at

We propose to use the Advanced Camera for Surveys to image four selected fields
in the outskirts of the rich, X-ray luminous cluster MS1054-03 at z=0.83. The
high-resolution and sensitivity of ACS is required in order to study the
properties of the population of galaxies falling into the cluster for the first
time. By targeting regions of the cluster well beyond the virial radius, we
will: {1} study the transformation of infalling field spirals into cluster
early-types using, e.g., the morphology-density relation to large radii and
low local densities; {2} determine the star-formation histories of those field
galaxies most recently accreted by the cluster, using accurate colors,
morphologies, bulge-to- disk ratios, bulge and disk scale lengths, M/L ratios
and line strengths; and {3} measure the frequency of galaxy-galaxy mergers and
interactions in the infall region. By combining wide-field HST/ACS data with
wide-field multi-object spectroscopy from the Magellan and Keck telescopes, we
can test the predictions made by galaxy formation models, study how field
spirals become early-type cluster members, and better constrain the formation
and evolution of galaxies in both clusters and the field.

ACS/WFC 9860

ESSENCE: Measuring the Dark Energy Equation of State

The accelerating universe appears to be dominated by a dark energy with a
significant negative pressure. The ratio of the pressure to density of this
mysterious energy {its equation of state} is an observable which can
differentiate between the proliferating candidate theories. We propose to
estimate the dark energy equation of state by observing Type Ia supernovae at
redshifts near z=0.7 with HST in concert with the on-going ESSENCE NOAO Survey
program that is discovering and studying supernovae between 0.3<z<0.8. We show
that an interesting constraint on the equation of state can be made with
supernovae observed at modest redshifts given the current knowledge of the
matter density. We will follow 10 Type Ia supernovae discovered from the ground
and passed to HST without disrupting its schedule. The full data set will
constrain the equation of state to 10% and strictly limit the range of possible
dark energy models. In keeping with the ESSENCE policy, these observations will
available to the community immediately.

NIC/NIC3 9865

The NICMOS Parallel Observing Program

We propose to continue managing the NICMOS pure parallel program. Based on our
experience, we are well prepared to make optimal use of the parallel
opportunities. The improved sensitivity and efficiency of our observations will
substantially increase the number of line-emitting galaxies detected. As our
previous work has demonstrated, the most frequently detected line is Halpha at
0.7<z<1.9, which provides an excellent measure of current star formation rate.
We will also detect star-forming and active galaxies in other redshift ranges
using other emission lines. The grism observations will produce by far the best
available Halpha luminosity functions over the crucial–but poorly
observed–redshift range where galaxies appear to have assembled most of their
stellar mass. This key process of galaxy evolution needs to be studied with IR
data; we found that observations at shorter wavelengths appear to have missed a
large fraction of the star-formation in galaxies, due to dust reddening. We
also obtain deep F110W and F160W images, to examine the space densities and
morphologies of faint red galaxies. In addition to carrying out the public
parallels, we will make the fully reduced and calibrated images and spectra
available on-line, with some ground-based data for the deepest parallel fields

NIC2 9726

A NICMOS search for obscured supernovae in starburst galaxies

Recent near-IR monitoring campaigns were successful in detecting obscured
supernovae {SNe} in starburst galaxies. The inferred SN rate is much higher
that obtained in previous optical campaigns, but it is still significantly
than expected by the high level star formation of these systems. One possible
explanation for the shortage of SNe is that most of them occur in the nuclear
region, where the limited angular resolution of groundbased observations
prevents their detection. We propose NICMOS SNAP observations of a sample of
starburst galaxies already observed once by NICMOS, with the goal of exploiting
its sensitivity and angular resolution to detect nuclear obscured SNe which
might have been missed by groundbased surveys. These observation will allow to
assess the real SN rate in starbust galaxies and deliver a sample of SN
occurring in the extreme environment of galactic nuclei. We expect to detect
more than 55 SNe {if the whole sample is observed}. If the number of SNe
detected in the program is much lower than expected it would prompt for a
revision of our understanding of the relation between the star formation rate
and the SN rate.

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


NICMOS Post-SAA calibration – CR Persistence Part 1.

A new procedure proposed to alleviate the CR-persistence problem of NICMOS.
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
darks will be non-standard reference files available to users with a USEAFTER
date/time mark.


NICMOS Post-SAA calibration – CR Persistence Part 2

A new procedure proposed to alleviate the CR-persistence problem of NICMOS.
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
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
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


The Origin of Gamma-Ray Bursts

The rapid and accurate localization of gamma-ray bursts {GRBs} promised by a
working HETE-2 during the coming year may well revolutionize our ability to
study these enigmatic, highly luminous transients. We propose a program of HST
and Chandra observations to capitalize on this extraordinary opportunity. We
will perform some of the most stringent tests yet of the standard model, in
which GRBs represent collimated relativistic outflows from collapsing massive
stars. NICMOS imaging and STIS CCD spectroscopy will detect broad atomic
features of supernovae underlying GRB optical transients, at luminosities more
than three times fainter than SN 1998bw. UV, optical, and X-ray spectroscopy
will be used to study the local ISM around the GRB. Chandra spectroscopy will
investigate whether the GRB X-ray lines are from metals freshly ripped from the
stellar core by the GRB. HST and CTIO infra-red imaging of the GRBs and their
hosts will be used to determine whether `dark’ bursts are the product of
unusually strong local extinction; imaging studies may for the first time
the hosts of `short’ GRBs. Our early polarimetry and late-time broadband
will further test physical models of the relativistic blast wave that produces
the bright GRB afterglow, and will provide unique insight into the influence of
the GRB environment on the afterglow.

STIS/CCD 10017

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD.

STIS/CCD 10019

CCD Bias Monitor – Part 1

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

STIS/CCD 10021

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
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 bimonthly

STIS/CCD 10085

STIS Pure Parallel Imaging Program: Cycle 12

This is the default archival pure parallel program for STIS during cycle 12.

STIS/MA1/MA2 10039

Spectroscopic Sensitivity Workout: First-order modes

We will observe the primary flux standards G191B2B, GD71 and GD153, obtaining
first-order spectra in all L-modes {G191B2B only in the CCD modes due to its
high brightness in the UV}. By comparing observed and model spectra, we will
update calibration reference files describing spectroscopic sensitivity
{and CTE
loss} as a function of time. On visit of GD71 will be spent on verifying the
recently derived CTE formula for STIS Spectroscopic modes with the CCD, by
stepping the target along the slit {7 positions} with two {short} exposure
times. This will verify the results using the two-amplifier readout method, and
provide high-S/N data at low intensity levels and low background level.

WFPC2 10068

WFPC2 CYCLE 12 Standard Darks

This dark calibration program obtains dark frames every week in order to
data for the ongoing calibration of the CCD dark current rate, and to monitor
and characterize the evolution of hot pixels. Over an extended period these
will also provide a monitor of radiation damage to the CCDs.

WFPC2 10069

WFPC2 CYCLE 12 Supplemental Darks, Part 1/3

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

WFPC2 10072


This calibration proposal is the Cycle 12 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.

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.


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

HSTAR 9262: GS Reacquisition (1,3,1) @ 005/12:23:46Z failed to Gyro control
with SSLE four times on FGS 1, beginning @
005/12:25:59Z. Primary
GS acquisition @ 005/10:48:09Z was successful. Under

HSTAR 9264: NICMOS suspended @ 006/00:01:43Z, received NICMOS Status
Buffer message
104 which states "while in boot mode, a Control
Section reset was detected",
however, we were not in Boot mode, in SAA
Operate. The parameter is 2,
which is a software reset, page fault intel
exception. This error is referenced
in KDDL #65. SISE, NASA, CHAMP, and STScI was
notified. A NICMOS dump was
executed @ 006/01:23:15Z.

Note: Recovery will be performed today when no NICMOS
activities are scheduled.
This error has been seen previously and is documented
in KDDL #65.

HSTAR 9265: GS Acquisition (3,2,3) @ 006/02:19:34Z resulted in FL backup
FGS2 due
to SSLE on FGS 3. Prior FM Updates @ 006/01:59Z and
02:02Z showed
good attitude error vector. Following GS
Reacquisition @ 006/03:55Z
will also fail to FLBU on FGS 2. FHST Map @
006/02:53:52Z showed 3-axis
errors of 13.965, -2.188, and -3.539 arcsec. Under



                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                 07                       07
FGS REacq                 07                       06              005/1226 
FHST Update               15                       15


HST Command Generator Ops Acceptance Testing scheduled 006/10:00Z – 007/02:00Z
with GDOC, HITT, SE, and VEST using CCS "B" String with CCS Release
PRD O06300T. The purpose of this testing is to verify installation and
procedures for the RAM version of Command Generator work in an operational

Electrical Power Subsystem: Off-lining -E and -D SPAs first opportunity
scheduled 006/15:45:30Z – 16:35:50Z.
See Ops Request 17077 with attached scripts.

SpaceRef staff editor.