Status Report

HST Daily Report # 3292

By SpaceRef Editor
February 3, 2003
Filed under , ,

HUBBLE SPACE TELESCOPE

DAILY REPORT        # 3292

PERIOD COVERED: DOYs 31-33

OBSERVATIONS SCHEDULED

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 9673

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 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.

ACS 9426

Jupiter’s Ring Plane Crossing of 2002-2003

Jupiter’s ring system consists of three components: the main band, the
vertically-extended inner halo and the exterior gossamer rings. Each
component
illustrates aspects of dust dynamics within Jupiter’s inclined magnetic
field
and its strong plasma environment. We will image all three components
with ACS
during an unusual, extended period of edge-on viewing, December 2002
through
February 2003. For faint planetary rings, this geometry improves the
signal-to-noise ratio considerably and permits an unambiguous decoupling
of
radial and vertical structure. Although the Jovian rings have been
examined by
four spacecraft and from the ground, we are still lacking in a systematic
set of
data that can distinguish between the ring’s prominent dust population
and its
embedded macroscopic source bodies. We also do not know the size
distribution of
dust with sufficient accuracy to test rival theories of ring origin.
Observations of the system at a range of wavelengths and phase angles
with ACS
will finally make this determination possible. Coordinated observations
at the
W. M. Keck Telescope will extend our wavelength coverage well into the
IR.

ACS 9401

The ACS Virgo Cluster Survey

We propose the most comprehensive imaging survey to date of low-redshift,
early-type galaxies. Our goal is to exploit the exceptional imaging
capabilities
of the ACS by acquiring deep images — in the SDSS g^ and z^ bandpasses
— for
163 E, S0, dE, dE, N and dS0 galaxies in Virgo, the nearest rich cluster.
This
extraordinary dataset would likely constitute one of the principal
legacies of
HST, and would have widespread applications for many diverse areas of
astrophysics. Our immediate scientific objectives are threefold: {1}
measure
metallicities, ages and radii for the many thousands of globular clusters
{GCs}
in these galaxies, and use this information to derive the protogalactic
mass
spectrum of each galaxy; {2} measure the central luminosity and color
profile of
each galaxy, and use this information to carry out a completely
independent
test
of the merging hierarchy inferred from the GCs, with the aid of N-body
codes
that simulate the merger of galaxies containing massive black holes; and
{3}
calibrate the z^ -band SBF method, measure Virgo’s 3-D structure, and
carry out
the definitive study of the GC luminosity function’s precision as a
standard
candle. Our proposed Virgo Cluster Survey will yield a database of
unprecedented
depth, precision and uniformity, and will enable us to study the record
of
galaxy and cluster formation in a level of detail which will never be
possible
with more distant systems.

ACS 9425

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

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/WFC 9433

The Size Distribution of Kuiper Belt Bodies

The Kuiper Belt is a population of remnant planetesimals from the
formation of
the Solar System. Since the planetesimals in extrasolar systems are too
faint to
see with present or planned telescopes, the Kuiper Belt is our best
chance to
test models of accretional/collisional evolution against observations.
Current
ground-based observations of Kuiper Belt Objects {KBOs} are consistent
with a
pure power law size distribution N{D}propto D^-q, q~4.3. Current
accretion
models predict a break to a shallower slope q=3.5 for objects of diameter
D<~100 km. We will conduct a survey of 6 ACS/WFC fields to detect KBOs with R<28.5, and diameters as small as D~10 km. The number of KBOs at these small sizes, unmeasurable from the ground, will test the existence of the predicted break with 95% confidence---we expect between 12 and 50 detections. A census of small KBOs is also important in confirming the idea that short-period comets are errant KBOs. With HST and ground- based followup, we can determine orbital parameters for the detected KBOs, and search for dynamical populations which may be deficient in D>100 km KBOs and hence not yet detected. In particular,
we
will
determine whether the current absence of objects with perihelia beyond 50
AU is
due to a truncation of the protoplanetary disk at some point in Solar
System
history, or just a failure to accrete D>150 km objects.

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

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
M_Jupiter.
An estimate of the inclination yields a perturbation semi-major axis,
Alpha =
0arcs0022, easily within the reach of HST/FGS astrometry.

FGS 9329

The Masses and Luminosities of Population II Stars

Very little is currently known concerning the mass-luminosity relation
{MLR} of
Population II stars. However, with the advent of the Hipparcos Catalogue,
improved distances to many spectroscopic binaries known to be Pop II
systems are
now available. After surveying the literature and making reasonable
estimates of
the secondary masses, we find 13 systems whose minimum separation should
be
larger than the resolution limit of FGS1. Because of the expected
magnitude
differences and separations, it is not possible to resolve the systems
from the
ground. We therefore propose FGS observations of the sample. In
combination
with
the known spectroscopic orbits and Hipparcos distances, these
observations will
yield up to 26 precise stellar mass determinations of metal-poor stars,
if all
systems are resolved and the relative orbits are determined. A
combination of
FGS data and ground-based observations will lead to component
luminosities and
effective temperatures. This program will allow for a significantly
better
understanding of the Pop II main sequence, which in turn will lead to
better
ages and distances of the galactic globular clusters, and a Pop II MLR
will be
constructed for the first time.

NICMOS 9485

Completing A Near-Infrared Search for Very Low Mass Companions to Stars
within
10 pc of the Sun

Most stars are fainter and less massive than the Sun. Nevertheless, our
knowledge of very low mass {VLM} red dwarfs and their brown dwarf cousins
is
quite limited. Unknown are the true luminosity function {LF},
multiplicity
fraction, mass function, and mass-luminosity relation for red and brown
dwarfs,
though they dominate the Galaxy in both numbers and total mass. The best
way to
constrain these relations is a search for faint companions to nearby
stars.
Such
a search has several advantages over field surveys, including greater
sensitivity to VLM objects and the availability of precise parallaxes
from
which
luminosities and masses can be derived. We propose to complete our
four-filter
NICMOS snapshot search for companions to stars within 10 pc. With a 10
sigma
detection limit of M_J ~ 20 at 10 pc, we can detect companions between 10
and
100 AU that are at least 9 mag fainter than the empirical end of the main
sequence and at least 6.5 mag fainter than the brown dwarf Gl 229B. When
completed, our search will be the largest, most sensitive, volume-limited
search
for VLM companions ever undertaken. Our four-filter search will permit
unambiguous identification of VLM-companion candidates for follow-up
observation. Together with IR speckle and deep imaging surveys, our
program
will
firmly establish the LF for VLM companions at separations of 1-1000 AU
and the
multiplicity fraction of all stars within 10 pc.

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 9702

NICMOS Parallel Thermal Background

NICMOS Camera 2 pure parallel exposures in the F222M and F237M filters to
establish the stability of the HST+NCS+Instrument thermal emission. This
data
will be compared against the already available Camera 3 measurements in
F222M
which show an increased thermal background.

NICMOS 8790

NICMOS Post-SAA calibration – CR Persistence Part 1.

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.

NICMOS 9484

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 stellarmass 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 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
columns.

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
lamp
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 9706

STIS Pure Parallel Imaging Program: Cycle 10

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

STIS 9505

The Evolution of Molecular Clouds.

The combined STIS, FUSE and ground-based results will yield information
needed
to understand the role of ablation in the evolution of the central
clouds.

STIS/CCD 9066

Closing in on the Hydrogen Reionization Edge of the Universe.

The Space Telescope Imaging Spectrograph (CCD) was used in parallel
constrain
the Hydrogen reionization edge in emission that marks the transition from
a
neutral to a fully ionized IGM at a predicted redshifts.

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 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

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: None

                        SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq            30                       30
FGS REacq            17                       17
FHST Update          53                       53
LOSS of LOCK

SIGNIFICANT EVENTS: None

SpaceRef staff editor.