Status Report

NASA Hubble Space Telescope Daily Report # 3481

By SpaceRef Editor
November 4, 2003
Filed under , ,





ACS/HRC 9987

Coronagraphic search for disks around nearby stars

We will use the coronagraphic and imaging modes of the High Resolution
camera to study of the role of circumstellar disks in planetary system
formation over timescales of ~1-1000 Myr. Our targets comprise pre
Main-Sequence {MS} and MS stars, selected by infrared excess, and
targets selected from SIRTF surveys. Some targets, like Beta Pictoris
have debris disks that have been detected at optical or near-IR
wavelengths, while others have disks inferred from mid-IR or ISO
observations. We will obtain multicolor images of each target’s
circumstellar environment for the purpose of {1} detecting and
characterizing disk morphologies over all scales {including warps and
regions of enhanced or depleted density}, and {2} seeking evidence of
embedded planets. Direct and occulted images will be recorded for
studying the disks within 2 arcseconds of these targets; the
coronagraph will be used to image the outer regions of the disks.
Together with existing infrared observations, we will provide
constraints on the sizes, distribution, and composition of dust

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 ideal.

ACS/HRC 9976

The Parallaxes and Proper Motions of Two Nearby Neutron Stars

We propose to measure the parallax of two nearby neutron stars to the
highest possible level of accuracy, ~.0.5 mas. The primary goal is to
determine the neutron-star radius at infinity with better than 1 km
precision, and therewith obtain a direct constraint on the equation of
state of matter at supra-nuclear density. The required flux and
temperature determinations are easiest for the so-called isolated or
radio-quiet neutron stars because of their apparently completely
thermal spectrum. We argue that the importance of the possible results
warrants a study to the best possible level of the best possible
sources, and request 24 orbits for the two brightest isolated neutron
stars, RX J1856.5-3754 and RX J0720.4-3125. We will also determine
whether the enigmatic RX J0720.4-3125 is an old magnetar or an
accreting source, based on its luminosity and proper motion.

WFPC2 9887

HST Observations of Astrophysically Important Visual Binaries

This is a continuation of a project begun in Cycle 7 and continued up
through Cycle 11. The program consists of annual or biannual WFPC2 or
FGS observations of three visual binary stars that will ultimately
yield fundamental astrophysical results, once their orbits and masses
are determined. Our targets are the following: {1} Procyon {P = 41
yr}, for which our first WFPC2 images yielded an extremely accurate
angular separation of the bright F star and its much fainter
white-dwarf companion. Combined with ground-based astrometry of the
bright star, our observation significantly revised downward the
derived masses, and brought Procyon A into excellent agreement with
theoretical evolutionary tracks for the first time. With the continued
monitoring proposed here, we will obtain masses to an accuracy of
better than 1%, providing a testbed for theories of both Sun-like
stars and white dwarfs. {2} G 107-70, a close double white dwarf {P =
19 yr} that promises to add two accurate masses to the tiny handful of
white-dwarf masses that are directly known from dynamical
measurements. {3} Mu Cas {P = 21 yr}, a famous metal-deficient G dwarf
for which accurate masses will lead to the stars’ helium contents,
with cosmological implications.

FGS 9881

Dynamical Masses and Radii of Four White Dwarf Stars

The cool white dwarf stars WD1639+153 and WD1818+126 were recently
resolved by HST FGS1r to be double degenerate binary systems with
projected separations of 112 mas and 174 mas respectively. At a
distance of less than 50 pc they may both have periods shorter than
about 20 years, making them ideal candidates for follow up studies for
dynamical mass determinations. This will increase the number of white
dwarfs with dynamical mass measurements from the current 4 up to 8.
Continued observations of these white dwarfs along with nearby field
stars with the FGS will accurately determine the orbital elements and
parallax of each system. The mass and radius of all four white dwarfs
can be determined to an unprecedented 1%, making it possible to test
and calibrate the theoretical white dwarf mass radius relation at the
cool end of the cooling curve for the DA and DC subclasses. Since the
components of the binary are coeval, once the mass and radius, and
hence the cooling age of each star is known, it will be possible to
estimate the relation between the initial mass and final mass for all
four white dwarfs. We are requesting a total of 4 HST orbits per year
for the next three cycles to initiate the process that will result in
a determination of the mass and radius of the four white dwarfs.

NIC/NIC3 9865

The NICMOS Parallel Observing Program

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at

ACS/WFC 9842

A Snapshot Search for Halo Very-Low-Mass Binaries

We propose a snapshot search for binary M subdwarf stars. These nearby
stars have high velocities and low metallicies that identify them as
members of the old Galactic halo {Population II}. ACS imaging is
requested to search for secondary companions. This supplements a
previous snapshot program that only obtained 10 observations. The
observed binary fraction will be compared to the disk M dwarf fraction
to look for differences in star formation. It is likely that a system
suitable for orbital mass determinations will be found. In this case,
future HST observations could determine the first masses for
very-low-mass, low-metallicity stars.

NIC1 9833

T Dwarf Companions: Searching for the Coldest Brown Dwarfs

Faint companions to known stars have historically led to the discovery
of new classes of stellar and substellar objects. Because these
discoveries are typically limited by the flux ratio of the components
in the system, the intrinsically faintest companions are most
effectively identified around the intrinsically faintest primaries. We
propose to use NICMOS to image a sample of 22 of the coolest known
{T-type} brown dwarfs in the Solar Neighborhood in order to search for
fainter and cooler brown dwarf companions. The high spatial resolution
of the NIC 1 detector enables us to distinguish binary systems with
apparent separations greater than 0″08, or physical separations
greater than 1.2 AU at the nominal distances of the objects in our
sample. Furthermore, the substantial sensitivity of NICMOS imaging
allows us to probe companion masses of 5-50 Jupiter masses and
companion effective temperatures of 250-1300 K in a maximally
efficient manner. Based on work to date, we expect that roughly 20% of
the objects in our sample will be binary, and that one or two of these
will likely harbor a significantly fainter secondary. Hence, we expect
to find a companion cooler than any currently known brown dwarf, a
potential prototype for the next spectral class. In addition, our
investigation will add substantially to the sample of known binary
brown dwarfs, allowing improved statistical analyses of the binary
fraction, separation distribution, and mass ratio distribution of
these systems, key quantities for probing brown dwarf formation. We
will also identify optimal substellar systems for astrometric mass
measurements, a critical check for theoretical models of brown dwarfs
and extrasolar planets.

ACS/WFC 9821

The Second Parameter Effect in Metal-Rich Globular Clusters: A
Snapshot Study of NGC 6388

While it has long been known that at least one parameter besides the
metallicity, [Fe/H], determines the horizontal branch {HB} morphology
of Galactic globular clusters {GCs}, our ignorance as to the nature of
this second parameter {or parameters} has been a major stumbling block
in understanding the formation history and age of the GC system. The
hot HB populations recently discovered by HST in the metal-rich GCs
NGC 6388 and NGC 6441 provide a unique opportunity for unraveling this
second-parameter effect. Many different theories have been proposed to
explain the pronounced upward slope of the HBs in these GCs, including
stellar rotation, metallicity spread, and a dwarf galaxy origin. We
propose to test these theories by obtaining B, V, I time-series
photometry of the RR Lyrae variables in the core of NGC 6388 in order
to determine whether, as predicted, the pulsation periods are
unusually long due to a high HB luminosity. If confirmed, this would
argue against age or mass loss as the second parameter in NGC 6388
and, more generally, would have implications for the use of RR Lyrae
stars as standard candles for determining GC distances and ages. Light
curves will also be obtained for the crowded Population II Cepheids
near the core of NGC 6388, the most metal-rich GC, along with NGC
6441, known to contain such stars. We waive proprietary rights to any
data obtained.


Deep NICMOS Images of the UDF

The ACS Ultra Deep Field {UDF} images will greatly enhance the rich
suite of deep multi-wavelength images in the Chandra Deep Field South
{CDF–S}. We propose to complete the image set with deep near-IR
NICMOS images at 1.1 and 1.6 microns over a significant fraction of
the UDF, providing a critical link between the HST ACS and SIRTF
observations. The timely addition of the near-IR images ensures that
investigators will have images that span the spectrum from X-ray to
far IR. In recognition of the value of the near IR images this
proposal is submitted as a Treasury proposal with no proprietary
period. The proposal team will deliver science quality images,
mosaiced images covering 4.9 sq arc min, and a photometric catalog
complete to an AB mag of 28.2 in both the F110W and F160W filters. The
program also delivers a parallel extremely deep ACS field, 8′ away,
that reaches to within 0.6 mag of the UDF in the same filters as the
UDF. The scientific program of the proposal team focuses on the star
formation history of the universe, evolved galaxies at high redshift,
galaxies at the epoch of reionization, and the redshift evolution of
AGNs and ULIRGs. The HDF-N is currently the only field with
spatially-coincident deep HST imaging in both the optical and near-IR.
The small size of the HDF-N means that large scale structure is the
dominant error in the results from the HDF-N. Providing observations
in a field that is spatially uncorrelated is critically important. The
UDF/CDF-S fulfills that goal. The depth of the UDF ACS imaging, and
the wealth of Great Observatory and ground based observations in the
CDF-S, make these NICMOS observations uniquely valuable. An
extraordinarily rich array of science opportunities await the
community from the NICMOS UDF data.

STIS 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters. This program is using the
low dispersion UV and optical gratings of STIS. The library will be
roughly equally divided among four metallicities, very low {[Fe/H] lt
-1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and
super-solar {[Fe/H] gt 0.2}, well-sampling the entire HR-diagram in
each bin. Such a library will surpass all extant compilations and have
lasting archival value, well into the Next Generation Space Telescope
era. Because of the universal utility and community-broad nature of
this venture, we waive the entire proprietary period.


Galaxy Evolution During Half the Age of the Universe: ACS imaging of
rich galaxy clusters

Detailed studies of nearby galaxies {z<0.05} have shown that galaxies have very complex histories of formation and evolution involving mergers, bursts of star formation, and morphological changes. Even so, the global properties of the galaxies {radii, luminosities, rotation velocities, velocity dispersions, and absorption line strengths} follow a number of very tight {empirical} scaling relations, e.g. the Tully-Fisher relation and the Fundamental Plane. These relations place constraints on models for galaxy evolution. The results for nearby galaxies rely on high signal-to-noise spectroscopy and multi-color photometry. With the Gemini Telescopes and the Hubble Space Telescope {HST} it is possible to carry out similar detailed studies of galaxies at much larger redshifts, up to z~1.0, equivalent to half the age of the Universe. We have started a project using the scaling relations and aimed at studying the galaxy evolution over the last half of the age of the Universe. The project is based on a large database of spectroscopy and photometry of galaxies in 15 X-ray selected clusters of galaxies with redshifts between 0.15 and 1.0. Spectroscopic observations are being obtained using both Gemini Telescopes; we have observed 6 clusters so far, covering from z=0.18 to z=0.83. We propose to use HST/ACS to image the clusters and determine the morphologies and measure the sizes of the galaxies. At this time we ask for 26 orbits to image four of the clusters in our sample.


Search for Black Holes in M31 Globular Clusters

Whether globular clusters contain a central massive black hole remains
a very controversial subject today, and yet is extremely important for
theoretical models for black hole and cluster formation. Furthermore,
the existence of intermediate-mass black holes has important
implications for supermassive black hole and galactic bulge formation,
as well as providing signatures in gravitational wave detectors. We
propose to obtain high spatial resolution, long-slit spectroscopy of
two globular clusters in M31, G78 and G280. These two clusters
represent the best ones in which to constrain a central black hole.
Most importantly, both of these clusters have long central relaxation
times, and thus confusion between a central black hole and a
collection of heavy stellar remnants is alleviated. We have considered
all globular clusters in our Galaxy and in M31; STIS observations of
these two will provide the strongest limits for a black hole in any
cluster, and better than the two claims made previously in the
literature. Combined with the data for G1, these three clusters have
the three highest central velocity dispersions for any cluster in the
Local Group and will shed light on possible connections between galaxy
and globular cluster formation.

ACS 9760

ACS Imaging of the Gemini Deep Deep Survey Fields: Galaxy Assembly at z = 1.5

We are presently carrying out the deepest redshift survey ever
undertaken {the Gemini Deep Deep Survey}. Spectra of extraordinary
quality have been taken in order to obtain redshifts in the so-called
“redshift desert” at 1

ACS/WFC 9744

HST Imaging of Gravitational Lenses

Gravitational lenses offer unique opportunities to study cosmology,
dark matter, galactic structure, galaxy evolution and quasar host
galaxies. They are also the only sample of galaxies selected based on
their mass rather than their luminosity or surface brightness. While
gravitational lenses can be discovered with ground-based optical and
radio observations, converting them into astrophysical tools requires
HST. HST has demonstrated that it is the only telescope that can in
each case precisely locate the lens galaxy, measure its luminosity,
color and structure, and search for lensed images of the source host
galaxy given the typical image separations of ~1”. We will obtain
ACS/WFC V and I images and NICMOS H images of 21 new lenses never
observed by HST and NICMOS H images of 16 lenses never observed by HST
in the IR. As in previous cycles, we request that the data be made
public immediately.

WFPC2 9712

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

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.

STIS 9633

STIS parallel archive proposal – Nearby Galaxies – Imaging and

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 S-type 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.

ACS/WFC 9575

Default {Archival} Pure Parallel Program.

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

ACS 9468

ACS Grism Parallel Survey of Emission- line Galaxies at Redshift z pl 7

We propose an ACS grism parallel survey to search for emission-line
galaxies toward 50 random lines of sight over the redshift interval 0
< z pl 7. We request ACS parallel observations of duration more than one orbit at high galactic latitude to identify ~ 300 HAlpha emission-line galaxies at 0.2 pl z pl 0.5, ~ 720 O IILambda3727 emission-line galaxies at 0.3 pl z pl 1.68, and pg 1000 Ly-alpha emission-line galaxies at 3 pl z pl 7 with total emission line flux f pg 2* 10^-17 ergs s^-1 cm^-2 over 578 arcmin^2. We will obtain direct images with the F814W and F606W filters and dispersed images with the WFC/G800L grism at each position. The direct images will serve to provide a zeroth order model both for wavelength calibration of the extracted 1D spectra and for determining extraction apertures of the corresponding dispersed images. The primary scientific objectives are as follows: {1} We will establish a uniform sample of HAlpha and O II emission-line galaxies at z<1.7 in order to obtain accurate measurements of co-moving star formation rate density versus redshift over this redshift range. {2} We will study the spatial and statistical distribution of star formation rate intensity in individual galaxies using the spatially resolved emission-line morphology in the grism images. And {3} we will study high-redshift universe using Ly-alpha emitting galaxies identified at z pl 7 in the survey. The data will be available to the community immediately as they are obtained.

STIS 9435

Systematic Search for Rotation at the Base of Outflows from T Tauri Stars

We wish to search for rotation signatures in the initial portion
{first 100 AU} of a sample of outflows emanating from T Tauri stars
{TTSs}. This project originates from our detection of systematic
transverse radial velocity shifts in STIS spectra of the DG Tau jet
{Bacciotti et al., 2002}. The shifts, observed in a region where the
flow is already collimated, but has not yet manifestly interacted with
its environment, are consistent with the predictions of magneto-
centrifugal launching models, and may constitute the first observed
indication for rotation in the initial portion of a jet flow. Rotation
is a fundamental ingredient in star formation theories, thus we
propose to confirm the above result by carrying out a systematic
survey in similar flows. We plan to take for each jet a STIS spectrum
in the 6300 — 6800 Angstrom range, with the slit perpendicular to the
flow direction and at a distance of about 0.”3 from the source {i.e.,
in our targets, 40 — 70 AU along the jet depending on inclination
angle}. Since the flows are resolved transversely with HST, the
proposed slit orientation allows for the direct detection of
systematic velocity shifts. Where found, we will check for
consistency between the sense of rotation observed and that of the
underlying disk through CO interferometric measurements. As a
by-product, estimates of the excitation conditions across the flow
{including ionization fraction} and of the mass outflow rates will be


Spectroscopy in the Inner Region of the 3C 48 Host Galaxy

As far as we are aware, there is only one host galaxy continuum
feature in a luminous QSO that is bright enough for practical STIS
spectroscopy: this is the bright peak ~1″ NE of the well-known quasar
3C 48. This feature {3C 48A} is enigmatic, with an apparently
distorted morphology. It may be the distended nuclear region of one of
the galaxies in this major merger. It might, instead, possibly be the
result of interaction of the compact-steep spectrum radio jet with
ambient material; but this seems unlikely because the correspondence
between the radio and optical morphologies is not very good. We also
know from ground-based and HST imaging that 3C 48A is overwhelmingly
dominated by continuum radiation, not line emission, and the colors
seem to be inconsistent with stars as young as the probable age of the
radio jet. Our previous high S/N ground-based spectroscopy of 3C 48
covered most regions of host galaxy beyond ~2″ from the QSO. From this
spectroscopy and spectral synthesis models, we have been able to
determine mean ages for recent starbursts in various parts of the host
galaxy as well as the velocity field of the stars. By tying the
proposed STIS spectroscopy of 3C 48A to our existing spectroscopy of
the host galaxy, together with archival PC images, we expect to be
able to determine the nature of this unusual inner structure and its
role in the evolutionary history of 3C 48.

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration – CR Persistence Part 3

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.

WFPC2 10082

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans

WFPC2 10069

WFPC2 CYCLE 12 Supplemental Darks, Part 1/3

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

ACS/HRC 10050

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth
with the HRC and WFC. These observations will be used to verify the
accuracy of the flats currently used by the pipeline and will provide
a comparison with flats derived via other techniques: L-flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronographic
monitoring is required to assess the changing position of the spots.

ACS/WFC 10049

ACS Internal Flat Field Stability

The stability of the CCD flat fields will be monitored using the
calibration lamps and a sub-sample of the filter set. High signal
observations will be used to assess the stability of the pixel-to-
pixel flat field structure and to monitor the position of the dust
motes. Shorter exposures will be used to identify charge traps and to
assess the stability of the DQ arrays. Only internal exposures with
the calibration lamps will be required.


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.

STIS/CCD 10030

STIS/CCD Spectroscopic Sensitivity Monitor for Cycle 12

Monitor sensitivity of each CCD grating mode to detect any change due
to contamination or other causes.

STIS/CCD 10019

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/CCD 10017

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD.

STIS/CCD 10000

STIS Pure Parallel Imaging Program: Cycle 12

This is the default archival pure parallel program for STIS during
cycle 12.


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

HSTAR 9184: STIS Target Acquisition image blank @ 268/07:44:10Z.
The OFINDSLT segment of the target acquisition sequence only contained
background noise counts. Under investigation.



                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                21                        21
FGS REacq                25                        25
FHST Update              50                        50


SpaceRef staff editor.