Status Report

NASA Hubble Space Telescope Daily Report # 3394

By SpaceRef Editor
June 30, 2003
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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 interval. 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
including 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 cosmological
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 9482

ACS Pure Parallel Lyman-Alpha Emission Survey {APPLES}

Ly-alpha line emission is an efficient tool for identifying young
galaxies at high redshift, because it is strong in galaxies with young
stars and little or no dust — properties expected in galaxies
undergoing their first burst of star- formation. Slitless spectroscopy
with the ACS Wide-Field Camera and G800L grism allows an unmatched
search efficiency for such objects over the uninterrupted range 4 <~ z
<~ 7. We propose the ACS Pure Parallel Ly-alpha Emission Survey
{“APPLES”}, to exploit this unique HST capability and so obtain the
largest and most uniform sample of high redshift Ly-alpha emitters
yet. Parallel observations will allow this survey to be conducted with
minimal impact on HST resources, and we will place reduced images and
extracted spectra in the public domain within three months of
observation. We aim to find ~ 1000 Ly-alpha emitters, 5 times the
biggest current sample of Ly-alpha emitters. This unprecedented sample
will provide robust statistics on the populations and evolution of
Ly-alpha emitters between redshifts 4–7; a robust measurement of the
reionization redshift completely independent of the Gunn-Peterson
trough; spatial clustering information for Ly-alpha emitters which
would let us probe their bias function and hence halo mass as a
function of redshift; many galaxies at redshift exceeding 6; and lower
redshift serendipitous discoveries.

ACS 9674

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.

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

ACS 9409

The Evolution of Globular Cluster Systems in Merger Remnants

Mergers seem to have played a major role in determining the shapes and
dynamics of elliptical galaxies. A few galactic mergers still occur
and offer valuable clues to past evolutionary processes. Globular
clusters formed during mergers are crucial probes for age-dating such
events, and help shed light on the process of cluster formation and
evolution. With young globulars in ongoing mergers now well studied,
we propose to make deep ACS observations of intermediate-age globular
clusters in two bona fide ellipticals: NGC 1316 and 3610. These
ellipticals have line-strength indices, UBV colors, and fine structure
indicative of their being 2 — 4 Gyr old merger remnants. Past
HST+WFPC2 observations have shown that they also possess significant
numbers of intermediate-age globulars as part of their bimodal cluster
populations. We plan to use the new HST+ACS observations to {1}
measure high-accuracy BVI colors for clusters up to ~ 2 — 3 mag
fainter than ever before, {2} use these colors to separate first- and
second-generation clusters, and {3} determine the luminosity functions
of the two kinds of clusters to 3 — 4 mag past the peak for old
globulars. Deep dithered BVI images form a crucial part of our
observing strategy. This program should permit—for the first
time—to directly detect the predicted evolution of the cluster
luminosity function from a power law for young clusters to the
Gaussian distribution typical of old globulars.

ACS 9454

The Nature of the UV Continuum in LINERs: A Variability Test

LINERs may be the most common AGNs, and the signposts of accretion
onto the massive black holes present in most galaxies. However, the
LINER spectrum is the result of UV excitation, and, in at least some
LINERs, a nuclear cluster of hot stars, rather than an AGN, dominates
the energetics in the UV. Thus, it is still unknown if the UV
continuum, or the optical emission lines it excites, have anything to
do with an AGN. The demographics and accretion physics of
low-luminosity AGNs hinge on this question. We propose to search for
variability in a sample of 17 LINERs with compact UV nuclei.
Variability can reveal an AGN component in the UV continuum, even when
its light is not dominant. We will test systematically the handful of
non-definitive reports of UV variability, and potentially quantify the
AGN contribution to the UV emission. Variability in all or most
objects will be strong evidence that LINERs mark dormant AGNs in most
galaxies. Alternatively, a general null detection of variability will
suggest that, even in LINERs with additional AGN signatures, the UV
continuum is stellar in origin. Contemporaneous monitoring with the
VLA/VLBA of 11 objects which have radio cores {five of which we
already know are radio-variable} will reveal the relations between UV
and radio variations. The UV-variable objects will be targeted for
future, better-sampled, monitoring.

ACS/HRC 9805

OGLE-TR-56b: The Most Interesting Transiting Planet

Our team has recently succeeded in confirming spectroscopically the
discovery of the first extrasolar giant planet found in a transit
search: OGLE-TR-56b. Its main parameters are: mass = 0.9 Jupiters,
size = 1.3 Jupiters. Thus, OGLE-TR-56b appears to be similar to HD
209458b, the only other known transiting giant planet. Unfortunately,
our planet radius determination is uncertain due to the very limited
precision of the ground-based photometry, and does not allow for a
meaningful comparison with theoretical model predictions. We propose
HST observations with the ACS-HRC of the main transit of OGLE-TR-56b,
which will improve the precision and the accuracy of the planet
parameters by close to a factor of 10. In addition, we propose a
timing experiment for the planet’s extremely close orbit {1.2-day
period, 0.023 AU from the star}, which will allow us to detect the
orbital decay and test convection theories.


Tracing the History of Cosmic Expansion to z~2 with Type Ia Supernovae

Type Ia supernovae {SNe Ia} provide the only direct evidence for an
accelerating universe, an extraordinary result that needs the most
rigorous test. The case for cosmic acceleration rests on the
observation that SNe Ia at z = 0.5 are about 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
SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia
peak luminosity would not show this change of sign. We have obtained a
toehold on this putative “epoch of deceleration” with SN 1997ff at z
= 1.7, and 3 more at z > 1 from our Cycle 11 program, all found and
followed by HST. However, this is too important a test to rest on just
a few objects, anyone of which could be subject to a lensed
line-of-sight or misidentification. Here we propose to extend our
measurement with observations of twelve SNe Ia in the range 1.0 < z <
1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be
discovered as a byproduct from proposed Treasury and DD programs.
These objects will provide a much firmer foundation for a conclusion
that touches on important questions of fundamental physics.

ACS/WFC 9575

Default {Archival} Pure Parallel Program.

The Advanced Camera for Surveys (WFC) was used to test ACS pure
parallels in POMS.

ACS/WFPC2 9481

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

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 morphological
k-correction, and the location of star formation within galaxies,
using a sample 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

FOC 9340

Determination of the Distances and Masses of 3 Galactic Cepheids

We propose to continue a successful observing strategy which enabled
us to accurately measure angular separations < 10^-2” with the FOC
for binaries with Cepheid primaries and main sequence B or A star
secondaries {our accuracy should improve to ~10^-3” with STIS}. Once
measurements are available at two carefully selected phases and these
are combined with spectroscopic orbits, the angular information will
enable the masses and distances for the binaries to be determined from
Newton’s laws and Euclidean geometry. The distances determinations
amount to bypassing two rungs of the cosmic distance ladder: the
moving-cluster distance to the Hyades and main sequence fitting of
clusters containing Cepheids. The mass determinations will provide the
first direct dynamical mass measurements for Cepheids, providing
sorely needed quantitative information on this poorly understood stage
of massive star evolution.

HST 9382

A Large Targeted Survey for z < 1.6 Damped Lyman Alpha Lines in SDSS QSO
MgII-FeII Systems.

We have searched the first public release of SDSS QSO spectra for
low-z {z<1.65} metal absorption lines and found over 200 large rest
equivalent width MgII-FeII systems. Previously, we empirically showed
that such systems are good tracers of large neutral gas columns, with
~50% being classical damped Lyman alpha {DLA} systems {N_HI>=2*10^20
cm^-2}. Here we propose to follow up a well-defined subset of 79 of
them to search for DLAs with 0.47<z<1.60. Only QSOs brighter than
g’=19 were selected. The QSO emission and DLA absorption redshifts
were constrained to virtually eliminate data loss due to intervening
Lyman limit absorption. Consequently, we expect to discover ~40 new
DLAs, which is a three-fold increase in this redshift interval. This
will significantly improve our earlier low-z DLA statistical results
on their incidence, cosmological mass density, and N_HI distribution.
The results will also allow us to better quantify the empirical DLA —
metal-line correlation. With this improved understanding, the need for
follow-up UV spectroscopy will lessen and, with the release of the
final database of SDSS QSO spectra {an ~25-fold increase}, the number
of low-z DLAs could be increased arbitrarily. Thus, the power of the
large and statistically-sound SDSS database in combination with a
proven technique for finding low-z DLAs will, over the next few years,
essentially solve the problem of making an accurate determination of
the cosmic evolution of the neutral gas component down to z~0.4.


Cycle 11 NICMOS dark current, shading profile, and read noise monitoring

The purpose of this proposal is to monitor the dark current, read
noise, and shading profile for all three NICMOS detectors throughout
the duration of Cycle 11. This proposal is a continuation of PID 9321
which covers the period between the end of SMOV3B and the onset of
Cycle 11.


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.


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 bursts and the build up of stellar mass at intermediate
redshifts. In addition to carrying out the parallel program we will
populate a public database with calibrated spectra and images, and
provide limited ground- based optical and near-IR data for the deepest
parallel fields.

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 9606

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS 9708

STIS Pure Parallel Imaging Program: Cycle 11

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

STIS 9783

The Ages of Nuclear Star Clusters in Early-type Spiral Galaxies

We propose to obtain STIS G430L spectra of the previously identified
nuclear star cluster in a sample of 16 spiral galaxies of early to
intermediate Hubble type. HST’s spatial resolution is required to
separate the nuclear cluster from the underlying galaxy bulge.
Analysis of the spectra with population synthesis methods will reveal
the cluster ages. We will use the age distribution to constrain the
duty cycle of nuclear cluster formation. Comparison of the results to
those for a larger sample of nuclear clusters in late-type, bulgeless
galaxies will allow us to investigate possible differences between the
formation mechanisms of nuclear clusters in early and late Hubble
types. Such differences might be expected because galaxy bulges show a
dichotomy: in late Hubble types, the surface brightness profiles are
best described by an exponential, while they follow a de Vaucouleurs
law in earlier types. Although the reason for this dichotomy is still
unknown, it is plausible that galaxy bulges have different formation
mechanisms at the two ends of the Hubble sequence. We know that {1}
nuclear cluster formation is linked to the funneling of gas towards
the nucleus via gravitational torques from stellar bars, {2} a nuclear
mass concentration can make bars unstable, and {3} unstable bars can
form bulges. Therefore, the age distribution of nuclear star clusters
contains important clues to the evolution of galaxy centers and
promises new insight into the origin of the Hubble sequence.

STIS 9359

The Old Star CS 31082-001, the Age of the Universe, and the Nature of the

We propose to observe the newly discovered r-process-element enhanced
star, CS 31082-001 {Fe/H ~ -2.9}, in order to determine abundances of
the heaviest stable elements, using absorption lines that are only
reachable in the near UV. This star is the only halo star for which a
uranium detection has been reported, and for which the U/Th
chronometer has been used to specify an age limit. In order to improve
the accuracy of the age determination from U/Th we require abundance
estimates of the daughter nuclides –Pb & Bi– for which only upper
limits have been obtained from ground-based observations. Such
estimates will provide crucial constraints on the initial production
ratio of U/Th, resulting in a more strict lower limit on the age of
this star’s progenitor, hence on the age of the Universe. Measurements
of 3rd-peak neutron-capture elements, such as Pt, Os, Ir, and Au, all
with lines in the 2400-3100 Angstrom range, will expand our knowledge
of element synthesis in the early Galaxy. Our recent ESO-VLT data
indicate that the neutron-capture elements in this star exhibit
different enhancements as compared with the previously known “
r-process star” CS 22892-052, an apparent anomaly that must be
resolved. CS 31082-001 is the ideal HST target in its class — it is
4-times brighter than CS 22892-052, and less affected by molecular
line blending. Consequently, these HST data will become the reference
in all future studies of similar stars.


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 synoptically observe
a dusty atmosphere on the planet. The UV observations will complement
broad-band 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


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.


Metallicity Determination in a Narrow Line Seyfert 1 Galaxy Using
Joint Chandra & HST Observations

By virtue of their extreme properties, NLS1s have given us crucial
leverage on the key physical parameters underlying the AGN phenomenon.
There is also suggestive evidence of super-solar abundance in some
NLS1s, possibly as a result of rapid nuclear star formation in the
early/rejuvenated phase of galaxy evolution. The goal of this proposal
is to measure accurately the metallicity in a NLS1 with high
resolution X-ray and UV spectroscopy. Observations of elements with
multiple ionization states in the X-ray band, and abundance sensitive
lithium-like nitrogen {NV} in the UV allow accurate determination of
ionization parameter, and thus metallicity. This is not only important
for understanding the NLS1 phenomenon, but also for investigating
evolutionary aspects of AGNS.

STIS/MA1 9466

SBS 1150+599: A Population III Planetary Nebula?

SBS 1150+599 is a puzzling emission-line object. Optical spectra
reveal only strong Balmer, He II and Ne V lines, along with a hot,
featureless continuum. We have recently partially resolved the HAlpha
emission in a ground-based image, and believe the object to be a new
halo planetary nebula, one of only handful known in the Milky Way. If
correct, its lack of significant O III and other forbidden emission
means that SBS 1150+599 has the lowest metallicity of any known
planetary nebula. Our estimate of the oxygen abundance places it 40
times lower than that of K 648 in the globular cluster M15, the
previous record holder, and would make it one of the most metal-poor
objects in the Galaxy. We propose obtaining ACS images of SBS 1150+599
to confirm that it is a planetary nebula and to determine its
morphology. Planetary nebulae in old populations may occur due to
binary-star merging, and the morphology may test this hypothesis. We
will also study the UV spectrum of SBS 1150+599 using STIS to confirm
the O/H value and estimate carbon and nitrogen abundances unobtainable
in the optical.

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 9816

Proper motion kinematics in Galactic bulge/bar fields

With this proposal we continue a successful programme to measure
proper motions in fields in the galactic bulge. We are able to reach
accuracies of ca 10km/s in transverse motion at a distance of 8kpc,
for thousands of stars per WFPC2 field. In combination with VLT
spectroscopic radial velocities and metallicity indices, we will be
able to construct a full dynamical and stellar-population model for
our Bulge. Previous fields in this programme were on the minor axis;
the fields proposed here {using first epoch observations from
1995-1998 from the archive} lie in the first quadrant, on the near
side of the Galactic bar. We also wish to establish first-epoch
observations in the 4th quadrant, where no suitable data exist so far.

WFPC2 9595


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


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

HSTAR 9064: GS Acquisition (1,2,2) @ 178/11:54:38Z resulted in FL
backup on FGS 1 due to SSLE on FGS 2 @ 17Under



1115-0 CCC IP CONFIG Connections @ 178/11:10z

                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              20                        20
FGS REacq              17                        17
FHST Update            43                        43


SM-4 SMGT Systems Readiness 3.1.1 test scheduled 181/10:00Z –
182/02:00Z with HITT SE, SOC, VEST, GDOC, NISN, Sys Admin, PACOR-A and
STScI using CCS "B" String with CCS Release and PRD S07200.
The purpose of this testing is to verify the ground system
configurations and interfaces necessary to support SM-4 hardware
SMGTs. This test will verify command and telemetry between the STOCC,
VEST, and supporting elements, as required, in both HST Ops and SM
configurations in support of SM-4 activities.

SpaceRef staff editor.