Status Report

HST Daily Report #3341

By SpaceRef Editor

April 15, 2003

Filed under Hubble Space Telescope, Space Telescope Science Institute, US

DAILY REPORT #3341

PERIOD COVERED: DOY 104

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.

ACS 9352

The Deceleration Test from Treasury Type Ia Supernovae at Redshifts 1.2
to 1.6

extraordinary result that needs a rigorous test. The case for cosmic
acceleration rests on the
observation that SNe Ia at z ~ 0.5 are ~ 0.25 mag fainter than they
would be in a universe without
acceleration. A powerful and straightforward way to assess the
reliability of the SN Ia measurement and
the conceptual framework of its interpretation is to look for cosmic
deceleration at z >= 1. This
would be a clear signature of a mixed dark-matter and dark-energy
universe. Systematic errors in the SN
Ia result attributed to grey dust or cosmic evolution of the SN Ia peak
luminosity would not show this
change of sign. We have demonstrated proof of this concept with a
single SN Ia, SN 1997ff at z = 1.7,
found and followed by HST. The results suggest an early epoch of
deceleration, but this is too
important a conclusion to rest on just one object. Here we propose to
use HST for observations of six
SNe Ia in the range 1.2 <= z <= 1.6, that will be discovered as a
byproduct from proposed Treasury
programs for high-latitude ACS surveys. Six objects will provide a much
firmer foundation for a
conclusion that touches on important questions of fundamental physics.

NICMOS 9386

Infrared Photometry of a Statistically Significant Sample of KBOs

While the discovery rate of Kuiper Belt objects is accelerating, the
physical study of this new region
of the solar system has been slowed by a lack of basic astrophysical
data. Photometric observations of
the majority of the more than 400 known KBOs and Centaurs are
rudimentary and incomplete, particularly
in the infrared. The multicolor optical-infrared photometry that exists
for a small subset of KBOs
often shows significant discrepancies between observations by different
observers. Their intrinsic
faintness puts them at the practical limits of ground-based systems. In
July 2001 we began what will be
the largest uniform sample of optical photometry of KBOs with a WFPC2
SNAPSHOT program that will
perform accurate photometry at V, R, and I on a sample of up to 150
targets. We seek to greatly enhance
the
value of this survey by obtaining J and H photometry on the same sample
using NICMOS. Combined optical
and infrared broad band photometry is a far more powerful tool for
physical studies than is either
alone. Our sample includes objects that will be observed at thermal
infrared wavelengths by SIRTF and
will be used with those data to derive the first accurate diameters,
albedos, and surface properties
for a large sample of KBOs.

NICMOS/STIS CCD 9405

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 locate the hosts of `short’
GRBs. Our early polarimetry and late-time broadband imaging 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.

ACS 9480

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.

WFPC2 9592

WFPC2 CYCLE 11 Standard Darks

calibration of the CCD dark current rate, and to monitor and
characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

WFPC2 9594

WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt2/3

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

WFPC2 9596

WFPC2 CYCLE 11 INTERNAL MONITOR

This calibration proposal is the Cycle 11 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.

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.

ACS 9649

ACS internal CTE monitor

The charge transfer efficiency {CTE} of the ACS CCD detectors will
decline as damage due to on-orbit
radiation exposure accumulates. This degradation will be closely
monitored at regular intervals,
because it is likely to determine the useful lifetime of the CCDs. All
the data for this program is
acquired using internal targets {lamps} only, so all of the exposures
should be taken during Earth
occultation time {but not during SAA passages}. This program emulates
the ACS pre-flight ground
calibration and post-launch SMOV testing {program 8948}, so that results
from each epoch can be
directly compared. Extended Pixel Edge Response {EPER} and First Pixel
Response {FPR} data will be
obtained over a range of signal levels for both the Wide Field Channel
{WFC}, and the High Resolution
Channel {HRC}.

ACS 9673

CCD Daily Monitor

for any source of noise in ACS CCD detectors. This programme will be
executed once a day for the
entire lifetime of ACS

FLIGHT OPERATIONS SUMMARY:

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

HSTARs: