Status Report

HST Daily Report # 3273

By SpaceRef Editor
January 6, 2003
Filed under , ,





ACS 9472

A Snapshot Survey for Gravitational Lenses among z >= 4.0 Quasars

Over the last few years, the Sloan Digital Sky Survey has revolutionized the
study of high-redshift quasars by discovering over 200 objects with redshift
greater than 4.0, more than doubling the number known in this redshift
The sample includes eight of the ten highest redshift quasars known. We propose
a snapshot imaging survey of a well-defined sample of 250 z > 4.0 quasars in
order to find objects which are gravitationally lensed. Lensing models
magnification bias predict that at least 4% of quasars in a flux-limited sample
at z > 4 will be multiply lensed. Therefore this survey should find of order 10
lensed quasars at high redshift; only one gravitationally lensed quasar is
currently known at z > 4. This survey will provide by far the best sample to
date of high-redshift gravitational lenses. The observed fraction of lenses can
put strong constraints on cosmological models, in particular on the
constant Lambda. In addition, magnification bias can significantly bias
estimates of the luminosity function of quasars and the evolution thereof; this
work will constrain how important an effect this is, and thereby give us a
better understanding of the evolution of quasars and black holes at early
epochs, as well as constrain models for black hole formation.

ACS 9647

CCD Daily Monitor Part I

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 9453

The Age of the Andromeda Halo

With the advent of the ACS, we can cross a critical threshold in the study of
galaxy formation: For the first time, we can resolve the old main sequence
in the Andromeda halo, and thus directly determine the ages of the halo
stars in
a giant galaxy other than our own. As the nearest giant galaxy, Andromeda
the best testing ground for understanding galaxy formation and evolution.
Resolution of its halo will tell us about its spread in age and metallicity,
thus providing a formation history. Via extensive simulations, we demonstrate
that we can unambiguously characterize the halo population via a deep
F606W/F814W color-magnitude diagram reaching below the main sequence turnoff.
The data will distinguish whether the halo formed quickly or through protracted
infall and merging episodes, and would detect even a few percent trace of
intermediate age stars. Our field was carefully chosen to meet two criteria: an
optimal stellar density ensuring adequate statistics while avoiding
overcrowding, and the inclusion of an Andromeda globular cluster matched to the
peak halo metallicity. We also propose very brief observations in the same two
bands of five Galactic globular clusters spanning a wide metallicity range,
establishing population templates in the ACS photometric system that will be
used to calibrate and interpret the Andromeda data.

ACS 9583

The Great Observatories Origins Deep Survey: Imaging with ACS

We propose a Treasury program of ACS imaging as part of the Great Observatories
Origins Deep Survey {GOODS}, covering 320{square}’, or 32* the area of the two
original WFPC2 HDFs, to within 0.5–0.8 mag of their depth in four ACS bands,
BViz. The two GOODS fields, the Hubble Deep Field North and Chandra Deep Field
South, are the premier deep survey areas from X– ray to radio wavelengths. ACS
data will provide unique angular resolution, sensitivity, and wavelength
coverage to close the gap between the deepest Chandra and SIRTF observations.
Supported by extensive imaging and spectroscopy from the VLT, Keck, Subaru,
NOAO, Gemini, VLA, JCMT, and other facilities, the combined GOODS data set will
make it possible to map the evolution of the Hubble sequence with redshift,
reconstruct the history of galaxy mass assembly, star formation and nuclear
activity from the epoch of reionization to the present, trace the growth of
density perturbations via cosmic shear, and, with properly phased z–band
observations, detect ~ 12 Type Ia supernovae at 1.2<z<1.8 to test the cosmic
acceleration and the presence of dark energy. All HST, SIRTF, Chandra, and
supporting GOODS data are non– proprietary, with science–quality images and
catalogs released on a timescale of months. This will constitute the deepest,
largest, and most uniform panchromatic data set ever assembled to study the
distant universe.


Cosmological Parameters from Type Ia Supernovae at High Redshift.

The Advanced Camera for Surveys (WFC and HRC) was used to obtain a Hubble
diagram of Type Ia supernovae {SNe Ia} that will be of long lasting value as a
record of the expansion history of the universe.

ACS/WFPC2 9481

Pure Parallel Near-UV Observations with WFPC2 within High-Latitude ACS Survey

In anticipation of the allocation of ACS high-latitude imaging survey{s}, we
request a modification of the default pure parallel program for those WFPC2
parallels that fall within the ACS survey field. Rather than duplicate the red
bands which will be done much better with ACS, we propose to observe in the
near-ultraviolet F300W filter. These data will enable study of the rest-frame
ultraviolet morphology of galaxies at 0<z<1. We will determine the
k-correction, and the location of star formation within galaxies, using a
that is likely to be nearly complete with multi-wavelength photometry and
spectroscopic redshifts. The results can be used to interpret observations of
higher redshift galaxies by ACS.

FGS 9347

FGS Astrometry of the Extrasolar Planet of Epsilon Eridani

We propose observations with HST/FGS in Position Mode to determine the
astrometric elements {perturbation orbit semimajor axis and inclination} of the
candidate extra-solar planet around the K2 V star Epsilon Eridani that has been
detected by Doppler spectroscopy. These observations will also permit us to
determine the actual mass of the planet by providing the sin{i} factor
which can
not be determined with the radial velocity method. High precision radial
velocity {RV} measurements spanning the years 1980.8–2000.0 for the nearby
{3.22 pc} star Epsilon Eri show convincing variations with a period of ~ 7 yrs.
These data represent a combination of six independent data sets taken with four
different telescopes. A least squares orbital solution using robust estimation
yields orbital parameters of period, P = 6.9 yrs, velocity K- amplitude = 19
m/s, eccentricity e = 0.6, projected companion mass M_B sin{i} = 0.83
An estimate of the inclination yields a perturbation semi-major axis, Alpha =
0arcs0022, easily within the reach of HST/FGS astrometry.

GO 9428

SINS: The Supernova Intensive Study– Cycle 11

Supernovae create the chemical history of the Universe, energize the
interstellar gas, form the spine of the extragalactic distance scale, and
provide the only direct evidence for an accelerating universe. SINS is a
to study supernovae, near and far. HST is the perfect match in field and scale
for spatially-resolved observations of SN 1987A. There, a violent encounter
between the fast-moving debris and the stationary inner ring is well underway.
Monitoring this interaction will help solve the riddles of stellar evolution
posed by the enigmatic three-ring system of SN 1987A. Our UV observations of
Ly-Alpha emission reveal a remarkable reverse shock that provides a unique
laboratory for studying fast shocks and a powerful tool for dissecting the
structure of the vanished star. For more distant events, we propose
Target-of-Opportunity observations. In addition to one bright new supernova in
Cycle 11 discovered by any search at any time, we propose to discover two
supernovae for study in the ultraviolet at times specified in advance,
using the
Lick Observatory Supernova Search. SINS will study the historic SN 1987A,
explore UV emission from supernovae, and press late-time observations of
supernovae into uncharted territory of infrared catastrophes, light echoes, and
stellar remnants.


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.


The NICMOS Parallel Observing Program

We propose to manage the default set of pure parallels with NICMOS. Our
experience with both our GO NICMOS parallel program and the public parallel
NICMOS programs in cycle 7 prepared us to make optimal use of the parallel
opportunities. The NICMOS G141 grism remains the most powerful survey tool for
HAlpha emission-line galaxies at cosmologically interesting redshifts. It is
particularly well suited to addressing two key uncertainties regarding the
global history of star formation: the peak rate of star formation in the
relatively unexplored but critical 1<= z <= 2 epoch, and the amount of star
formation missing from UV continuum-based estimates due to high extinction. Our
proposed deep G141 exposures will increase the sample of known HAlpha emission-
line objects at z ~ 1.3 by roughly an order of magnitude. We will also obtain a
mix of F110W and F160W images along random sight-lines to examine the space
density and morphologies of the reddest galaxies. The nature of the extremely
red galaxies remains unclear and our program of imaging and grism spectroscopy
provides unique information regarding both the incidence of obscured star
and the build up of stellar mass at intermediate redshifts. In addition to
out the parallel program we will populate a public database with calibrated
and images, and provide limited ground- based optical and near-IR data for the
deepest parallel fields.


A SNAPSHOT Survey of the Hot Interstellar Medium

We propose to obtain SNAPSHOT STIS echelle observations of key tracers of hot
interstellar gas {CIV, NV and SiIV} for selected FUSE Team OVI survey targets
with known UV fluxes. By taking advantage of the SNAPSHOT observing mode we
efficiently obtain a large number of spectra suitable for the study of the
highly ionized hot component of the interstellar medium {ISM}. Our goals are to
explore the physical conditions in and distribution of such gas, as well as to
explore the nature of the interfaces between the hot ISM and the other
interstellar gas phases. Using inter–comparisons of the various ionic ratios
for CIV, NV, OVI and SiIV, we will be able to discriminate between the various
models for the production of the highly ionized gas in the Galactic ISM. The
survey will also enable detailed studies of regions already known to
contain hot
gas through X-ray emission measurements {e.g., SNRs and radio loops}. The
proposed SNAPSHOT observations will extend our previous Cycle 9 survey {which
was compromised by the STIS side 1 failure}, and should roughly double the
number of stars for which high quality STIS observations of the important hot
gas tracers are available, enabling us to derive a truly global view of the hot

STIS 9607

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 9605

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD

STIS 9624

STIS FUV-MAMA Cycle 11 Flats

This program will obtain FUV-MAMA observations of the STIS internal Krypton
to construct an FUV flat applicable to all FUV modes

STIS 9625

STIS NUV-MAMA Cycle 11 Flats

This program will obtain NUV-MAMA observations of the STIS internal Deuterium
lamp to construct an NUV flat applicable to all NUV modes

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
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.

STIS 9706

STIS Pure Parallel Imaging Program: Cycle 10

This is the default archival pure parallel program for STIS during cycle 10.


MAMA Sensitivity and Focus Monitor Cycle 11

Monitor sensitivity of each MAMA grating mode to detect any change due to
contamination or other causes. Also monitor the STIS focus in a spectroscopic
and imaging mode.


Towards a global understanding of accretion physics –, Clues from an UV
spectroscopic survey of cataclysmic variables

Accretion inflows and outflows are fundamental phenomena in a wide variety of
astrophysical environments, such as Young Stellar Objects, galactic binaries,
and AGN. Observationally, cataclysmic variables {CVs} are particularly well
suited for the study of accretion processes. We propose to carry out a STIS UV
spectroscopic snapshot survey of CVs that fully exploits the diagnostic
potential of these objects for our understanding of accretion physics. This
survey will provide an homogenous database of accretion disc and wind outflow
spectra covering a wide range of mass transfer rates and binary
inclinations. We
will analyze these spectra with state-of-the-art accretion disc model spectra
{SYNDISK}, testing our current knowledge of the accretion disc structure, and,
thereby, providing new insight into the so far not well understood process of
viscous dissipation. We will use our parameterised wind model PYTHON for the
analysis of the radiation driven accretion disc wind spectra, assessing the
fundamental question whether the mass loss rate correlates with the disc
luminosity. In addition, our survey data will identify a number of systems in
which the white dwarf significantly contributes to the UV flux, permitting an
analysis of the impact of mass accretion on the evolution of these compact
stars. This survey will at least double, if not triple, the number of
high-quality accretion disc / wind outflow / accreting white dwarf spectra, and
we waive our proprietary rights to permit a timely use of this database.

WFPC2 9598

Earth Flats

This proposal monitors flatfield stability. This proposal obtains sequences of
Earth streak flats to construct high quality flat fields for the WFPC2 filter
set. These flat fields will allow mapping of the OTA illumination pattern and
will be used in conjunction with previous internal and external flats to
generate new pipeline superflats. These Earth flats will complement the Earth
flat data obtained during cycles 4-10.

WFPC2 9394

Halo Microlensing: Direct Detection of a Microlens

The MACHO project has recently released 5.7 years of LMC microlensing data,
presenting 17 candidate microlensing events. These events suggest an 8-50 MACHO
halo and a most likely MACHO mass of 0.2-0.9 M_odot. However, nearly a decade
after the first reported event {Alcock et al. 1993} there still remains much
debate about the nature and location of the lensing matter. MACHO has also
obtained WFPC2 follow-up data of the microlensing source stars, to date we have
observed 16 candidates with HST. The WFPC2 follow-up data of MACHO event LMC-5
provided unexpected insight into the nature of the lens. This image revealed a
very red, faint object displaced by 0.134^ from the source star which may well
be the first direct detection of the dark matter component {lens} of a
microlensing event. A second epoch of WFPC2 photometry will verify the proper
motion of the lens and allow for a parallax measurement of its distance.

WFPC2 9699

POMS Test Proposal: WFII backup parallel archive proposal

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

WFPC2 9676

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 9634

POMS Test Proposal: WFII targeted parallel archive proposal

The parallel opportunities available with WFPC2 in the neighborhood of bright
galaxies are treated in a slightly different way from the normal pure
Local Group galaxies offer the opportunity for a closer look at young stellar
populations. Narrow-band images in F656N can be used both to identify young
stars via their emission lines, and to map the gas distribution in star-forming
regions. Thus, the filter F656N is added to the four standard filters. Near
distant galaxies, up to about 10 Mpc, we can map the population of globular
clusters; for this purpose, F300W is less useful, and only F450W, F606W, and
F814W will be used.

WFPC2 9593


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

WFPC2 9599

WFPC2 Cycle 11 UV Earth Flats

Monitor flat field stability. This proposal obtains sequences of earth streak
flats to improve the quality of pipeline flat fields for the WFPC2 UV filter
set. These Earth flats will complement the UV earth flat data obtained during
cycles 8-10.


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


OPS NOTES EXECUTED: 1051-1 FGS #3-6 Temperature Increase @003/1946z

                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              24                        24
FGS REacq              24                        24
FHST Update            41                        40        @005/0945z 


SpaceRef staff editor.