Status Report

HST Daily Report # 3259 9 Dec 2002

By SpaceRef Editor
December 9, 2002
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 9669

ACS coronagraph stability and vignetting

This is a two-part activity for the purposes of {1} monitoring the
positions ACS
coronagraph’s occulting spots and the “Fastie Finger, ” and {2} determining the
vignetting effects and the ability to flat field images of both point and
extended sources near the edges of the spots and finger.

ACS 9463

Are OH/IR stars the youngest post-AGB stars? An ACS SNAPshot imaging survey

Essentially all well-characterized preplanetary nebulae {PPNs}– 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
propose an ACS/SNAPshot imaging survey of a large, morphologically unbiased
sample of these objects, selected using their IRAS 12-to-25micron colors. Our
ground-based imaging study of OH/IR stars has revealed a few compact bipolar
objects, supporting our hypothesis. However since most objects remain
unresolved, HST observations are needed to determine how and when the bipolar
geometry asserts itself. 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
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 PPNs, are common or rare phenomena.

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 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
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 9399

Insights into Elliptical Galaxy Formation from HST Imaging of Shell Galaxies

We propose to use ACS to carry out an imaging survey of the cores of shell
galaxies. Key to understanding several aspects of shell formation is to
determine how far in do shells exist. Photometric detection from the ground is
limited by seeing and sampling to radii of at best R ~ 10 – 15 arcsec. In
velocity maps derived from high spatial resolution long-slit and integral-field
ground-based spectra we have found shell-like features with distinct kinematics
in several shell galaxy cores {R ~ 3 – 5 arcsec ~ 1 kpc}. Hence we believe that
shells may extend further in than previously known. HST provides the spatial
resolution and sampling needed to map out shells in the pronounced surface
brightness gradients of elliptical galaxy cores. The data will allow us to
detect and map inner shells, to measure their colors, to establish their
dynamics with the help of ground-based kinematics, to compare the inner surface
brightness profiles of shell and non-shell ellipticals, and to measure the mass
and distribution of the dust. Where shells are found, combined spatial and
velocity information will establish the orbital structure of shell- producing
merger debris on the basis of data, and will allow useful checks of the models
for formation of shell systems in early-type galaxies.

ACS 9705

M87 Jet

As the nearest galaxy with an optical jet, M87 affords an unparallelled
opportunity to study extragalactic jet phenomena at the highest resolution.
Monitoring of the jet of M87 by Chandra and HST has detected massive
in one knot of M87’s jet. During March-July 2002, knot HST-1 brightened by a
factor of 2 in both X-rays and optical. Following those observations, M87
unobservable, as in August-October the Sun approaches to within 5 degrees.
Chandra monitoring resumes in November; however, there are no HST observations
of M87 scheduled until May 2003. We therefore request five HST observations
during the period November 2002-April 2003, scheduled to correspond with the
Chandra observations. Based on its track record of X-ray variability in the
year, and optical variability and superluminal motion {speeds of 6c} since
we expect continued variability, with comparable timescales. The proposed
observations will monitor the optical morphology, spectrum and magnetic field
configuration of the jet, and allow us to model the mechanisms responsible for
this variability, the first seen in a spatially resolved jet. The results of
this investigation are of key importance not only for understanding the nature
of the X-ray emission of the M87 and its relationship to the lower energy,
radio-optical continuum, but also for understanding flares in blazar jets,
are highly variable but where we have never before been able to resolve the
flaring region in the optical or X-rays. Given the SED observed in M87, the
flare emission is probably synchrotron radiation from a fresh particle
threshold. Not only will these observations allow us to check this hypothesis,
they will allow us to constrain the particle acceleration and loss
timescales as
well as the jet dynamics {which produce and affect the magnetic field
configuration} associated with this flaring component.

ACS 9656

Stability of the ACS CCD: geometry, flat fielding, photometry

A moderately crowded stellar field, located ~6′ West of the centre of the
cluster 47 Tuc, is observed repeatedly {every three weeks with the WFC, every
other month with the HRC} in various filters, spending 1 orbit per epoch.
Different filters will be used every time, so that over the course of the year
all filters will have been employed at least twice. The most common filters
be checked more frequently. The same field has been observed in the course of
the SMOV phase and the positions and magnitudes of the most prominent stars
been accurately measured. Although the field is neither a proper
astrometric nor
a proper photometric standard one, the positions and magnitudes of the objects
in it can be used to monitor any local and large scale variations in the
platescale and sensitivity of the detectors. It should be noted that for the
filters which have already been used during the SMOV phase it will be
to take one single image, without CR-SPLIT, since the exposure time is always
short {20-30 sec} and there will be so many stars that the few of them
which are
affected by cosmic rays can be discarded as outliers in the photometry. For
narrow and medium band filters not exercised on this target in the SMOV phase,
however, a baseline will have to be set. This expenditure of time will apply to
the current cycle only. At variance with the approach used in SMOV, there is no
need for large telescope slews to place the same objects on opposite sides of
the detectors, thence allowing the programme to remain compact and efficient.
All exposure level parameters are set to their default values, except for the
amplifier gain of the WFC exposures in the F606W band, which will be collected
with the gain value of 2 for the WFC for compatibility with the SMOV
observations. The exposure time is typically 30 seconds for the WFC, 60 sec for
the HRC. No attempt will be made to attain a predefined or the same orientation
on the sky amongst different epochs. Typically, for the WFC, five exposures
be accommodated in one orbit. For the HRC, about 10 exposures can be fitted
within one orbit

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

ACS/HRC 9379

Near Ultraviolet Imaging of Seyfert Galaxies: Understanding the Starburst-AGN

We propose a near-UV snapshot survey of 101 Seyfert galaxies using ACS/HRC and
the filter F330W, a configuration which is optimal to detect faint star forming
regions around their nuclei. These images will complement optical and near-IR
images available in the HST archive, thus providing a panchromatic atlas of the
inner regions of active galaxies, which we will use to study the starburst-AGN
connection. The main goals of this proposal are: {1} Determine the frequency of
circumnuclear starbursts in Seyferts, down to levels which cannot be observed
from the ground; {2} characterize the observational {fluxes, colors, structure,
sizes} and intrinsic {luminosities, masses, ages, global star-formation rate}
properties of these clusters; {3} derive the luminosity functions of young star
clusters around the nucleus of Seyferts and compare these results with those
from normal and starburst galaxies to determine their survival rate close
to the
AGN; {4} address questions about the relation between AGNs and starbursts, like
the possible connection between the masses and luminosities of black holes and
starbursts, and the implications for the evolution of the black holes and their
host galaxy bulges. By adding UV images to the existing optical and near-IR
ones, this project will create an extremely valuable database for astronomers
with a broad range of scientific interests, from the properties of the AGN to
the properties of their host galaxies.


Spatially-resolved polarimetry of Titan

Titan’s stratospheric haze not only hides the surface in visible light, it also
traces the progress of Titan’s seasons and controls the solar flux into the
troposphere. Since 1994, we have monitored the seasonal context on Titan. We
propose to continue this program and, with ACS and NICMOS, we can add important
new measurements. Spacecraft polarimetry has suggested small particles, while
high phase angle images suggest larger particles. Two types of models have been
used to successfully explain the discrepancy: larger particles held above
smaller particles by Titan’s atmospheric dynamics; or a more uniform
distribution of fluffy aggregate aerosols. The distinction is not just a
question of large particles vs. small, it is about the process that governs the
evolution of Titan’s haze. New constraints have been slow in coming. Titan’s
disk integrated polarization near zero-phase angle does not distinguish the
models. Intensity alone does not distinguish the models. We have the
to make a set of observations that can test the models. We propose to obtain
disk-resolved polarization measurements from 0.2 to 2 micron. We will use this
information to develop a set of constraints on the type of particles in Titan’s
stratosphere. We will also continue our program of monitoring seasonal
change on
Titan, and use the data sets to provide context to the Cassini mission

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

CAL/WF2 9597

Intflat Sweep, Visflat Sweep, and Filter Anomaly Check

No abstract available.

FGS 9229

Orbits of Pre-Main Sequence Binaries

Our goal is to dynamically measure the masses of low mass pre-main sequence
stars. This is important because there are still no such objects with an
accurately measured mass. In cycle 5 we began to map the orbits of young
multiple star systems in Taurus using FGS3. In cycle 8 we switched to the more
capable FGS1r. We propose to continue to observe these binary and triple
so that we can establish their visual orbits. In addition to our Transfer mode
observations, we include Position mode observations of reference field stars so
that the position of the multiple systems’ barycenter can be located,
giving the
relative masses of the components. In addition, the Position mode data will
allow us to determine accurate parallaxes for these systems, and hence the
physical, absolute masses of the young pre-main sequence stars along with
absolute magnitudes.


NICMOS Focus Stability

The purpose of this activity is to determine if the best focus determined in
SMOV is stable. This program will execute in approximately one month intervals
starting about 1 month after the last execution of proposal 8980.


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 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.

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 9604

STIS CCD Performance Monitor

This activity measures the baseline performance and commandability of the CCD
subsystem. Only primary amplifier D is used. Bias and Flat Field exposures are
taken in order to measure bias level, read noise, CTE, and gain. Numerous bias
frames are taken to permit construction of “superbias” frames in which the
effects of read noise have been rendered negligible. Full frame and binned
observations are made, with binning factors of 2 x 1, 1 x 2, 2 x 2, 4 x 1,
and 4
x 2. Dark images are taken in 2×2 binning mode; 1×1 binning darks are being
taken in the nominal CCD Dark Monitor. Bias frames are taken in subarray
readouts to check the bias level for ACQ and ACQ/PEAK observations. All
exposures are internals.

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 9692

STIS Pure Parallel Imaging Program: Cycle 10

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


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 analyse 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.


The Black Hole {?} in BG Gem.

The Space Telescope Imaging Spectrograph (CCD, MA1 and MA2) was used to acquire
low resolution ultraviolet spectra of the long period black hole binary
candidate BG Geminorum. These spectra allow an unambiguous test of the
nature of
the 4.5 M{sun} primary star, which makes no measurable contribution to the
optical spectrum. Detection of a strong ultraviolet continuum or ultraviolet
absorption lines from Si II and Si III {among others} would indicate a B-type
primary; failure to detect these features or detection of high ionization
emission lines would favor a black hole primary. If it contains a black
hole, BG
Gem would be the longest period black hole binary known {by a factor of ten},
challenging current theories of black hole formation. It would also be the only
eclipsing binary known to contain a black hole, which would provide a unique
laboratory for testing accretion disk models for black hole binary systems.

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 9593


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


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

HSTAR 8879: During ZOE, GS Acquisition (2,1,1) @ 342/21:12:38Z failed to
gyros only due to SRLE on FGS 2. FM Update on FHST 1,2 @
showed errors of 7.272, 7.303, and 13.247. Following FHST
Map @ 342/21:56:23Z
showed errors of 18.148, -0.009, and 15.261. Following GS
(2,1,1) @ 342/22:50:57Z also failed due to SRLEX on FGS 2.
The guide star
acquisition for this observation was non-nominal, further
analysis will
determine if a repeat observation is required.


16882-1 STIS Science Data Erase @340/1645z


1056-3 Change STIS Error Counter Limit @340/2141z, Closed 341/1140z

                             SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                 27                        26        342/2112z 
(HSTAR 8879)
FGS REacq                 23                        22        342/2251z 
(HSTAR 8879)
FHST Update               60                        60


Real Time Data Lost due to Event Reschedule 340/1626-1643z

SpaceRef staff editor.