Status Report

HST Daily Report # 3276

By SpaceRef Editor
January 9, 2003
Filed under , ,






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.

ACS 9293

Massive Black Holes in Early Type Galaxies

Recently, a nearly perfect relation has been recognized between the masses of
the black holes {for 3×10^6 Msun < M_BH < 3×10^9 Msun} at the centers of
galaxies and the velocity dispersions of their bulges. However, uncertainties
over the exact slope of the correlation still remain, and it is not known if
such a relation extends to black holes of lower and higher masses. The
of small {r ~ a few hundred pc}, well defined, dust and gas disks in the nuclei
of some active elliptical galaxies opened a new avenue for measuring central
mass distributions. When ionized gas is present, a small number of high spatial
resolution {e.g. STIS} spectra are sufficient to characterize the disk dynamics
and the galaxy’s central mass {e.g., M87, M81, NGC 4374}. We propose to use
spectroscopy to measure black hole masses, using gas dynamics, in the
centers of
several brightest cluster galaxies {BCGs}, 2 nearby galaxies with low velocity
dispersions, and a number of elliptical galaxies known to harbor small nuclear
dust disks. The proposed targets encompass a wide range of black hole masses,
allowing us to fully examine the M_BH — sigma relationship. We will also
H-alpha and continuum images to fully characterize the gaseous and dust
morphology as well as stellar surface profile in the central regions.

WFPC2 9334

Dynamical Masses of White Dwarfs from Resolved Sirius-Like Binaries

In Cycle 8 we initiated a WFPC2 snapshot survey for resolved, “Sirius-like”
systems containing hot white-dwarf companions of cooler main-sequence
stars. Out
of 17 systems observed to date, 8 have been resolved with WFPC2 by using UV
filters. Two of the resolved systems—56 Persei and Zeta Cygni—have
or known orbital periods short enough that dynamical masses can be determined
for the white dwarfs within reasonable times. These would thus add to the
extremely small number of white dwarfs presently having accurately and directly
measured masses. We propose to image them annually in the UV with WFPC2. In
addition, we will observe Zeta Cyg with FGS in order to measure the absolute
motion of the optical component, needed for the mass solution. We also propose
to observe Sirius itself with WFPC2 over the next 3 Cycles. The resulting
astrometric data will not only greatly improve the precision of the binary
and the dynamical mass measurements for both the main-sequence and white-dwarf
components, but will also test definitively for the claimed presence of a third
body in this famous system.


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
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 Orbiter.

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
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
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 Imaging and STIS Spectroscopy of Binary Brown Dwarfs

We have compiled a sample of 9 spatially resolved binary brown dwarfs {18
objects}, and now propose ACS imaging and STIS spectroscopic follow-up
observations. While theoretical models on the interplay of chemical and
processes governing brown dwarf atmospheres have reached a high level of
sophistication, interpretation of observational data remains difficult. As
dwarfs never stabilize themselves on the hydrogen main sequence, there is
an ambiguity between the temperature or luminosity of any brown dwarf and its
mass or age. The individual components of brown dwarf binaries, however, are
expected to be coeval and have the same underlying chemical composition. This
provides crucial constraints on any model, thus greatly reducing the number of
the free parameters. The aim is to obtain photometric and spectroscopic data to
probe the physical and chemical properties of the brown dwarf atmospheres, as
well as second epoch astrometric data to characterize the orbital motion. The
study will provide important feedback on theoretical model atmospheres and
evolutionary tracks for brown dwarfs. As such, it will be an important step
towards a better understanding of objects with spectral properties intermediate
between those of giant planets and late-type stars.

WFPC2 9458

Probing the Formation & Evolution of M31’s Outer Disk and Halo

The fossil record of galaxy formation and evolution is imprinted on the spatial
distribution, ages and metallicities of galactic stellar populations. The
observations proposed here build significantly upon our extensive ground-based
and archival WFPC2 programs and aim to constrain the formation and evolution of
our nearest large neighbour, M31. We propose deep imaging of 8 fields in the
outer disk and halo, several of which have been identified from our panoramic
ground-based CCD survey {covering ~ 26 square degrees} to possess significant
stellar density and/or potential metallicity variations. Deep colour-magnitude
diagrams reaching ~2-3 magnitudes below the horizontal branch will be
constructed, allowing detailed characterization of the luminous evolved stellar
populations via the red giant metallicity distribution, the luminous asymptotic
giant branch, the horizontal branch morphology and the red clump, as well
as the
detection of a main-sequence that may be present from any younger
component. Our
primary goals are to: {i} quantify the stellar population variations associated
with M31 halo substructure, including the newly- discovered giant stellar
stream, and {ii} derive stringent constraints on the age and metallicity of
stars in the far outer disk. These observations will directly address two key
predictions of cold dark matter hierarchical galaxy formation models.

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.


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.
a search has several advantages over field surveys, including greater
sensitivity to VLM objects and the availability of precise parallaxes from
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
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
firmly establish the LF for VLM companions at separations of 1-1000 AU and the
multiplicity fraction of all stars within 10 pc.

ACS/WFC 9503

Milli-arcsec Registration of Nuclear Optical and Radio Structures in the
Seyferts NGC 1068 and NGC 4151

We propose to obtain accurate {as good as ~15 milli-arcsec} absolute positions
for the complex optical continuum and emission-line structures in the nuclei of
NGC 1068 and NGC 4151, by bootstrapping positions from Hipparcos catalog stars
in the same ACS/WFC field-of-view. This will also allow us to obtain accurate
absolute positions for the central engine – as traced by HST imaging
in NGC 1068, and by kinematics of emission-line clouds in NGC 4151. The
positions of the optical features will be compared with those of the complex
milli-arcsec-scale nuclear radio structures in order to: {a} identify the radio
component corresponding to the central engine or determine if it is absorbed;
{b} use the central engine position, in conjunction with already determined
nuclear radio structure and free-free- and H I- absorption to the nuclear radio
sources, to construct a more accurate model for the central engine and
torus in AGN; {c} look for detailed correlations {or lack thereof} between the
radio jets and the emission-line gas at the milli- arcsec level. An absolute
position determination makes all prior and future HST observations of these
galaxies more useful. Prompt observations are required as the position
uncertainties of the Hipparcos stars are increasing with time. In case of
technical problems with ACS, the goals of the project can be achieved with

WFPC2 9593


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

WFPC2 9598

Earth Flats

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

STIS 9605

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD

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 9624

STIS FUV-MAMA Cycle 11 Flats

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

STIS 9625

STIS NUV-MAMA Cycle 11 Flats

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

STIS 9633

STIS parallel archive proposal – Nearby Galaxies – Imaging and Spectroscopy

Using parallel opportunities with STIS which were not allocated by the TAC, we
propose to obtain deep STIS imagery with both the Clear {50CCD} and Long-Pass
{F28X50LP} filters in order to make color-magnitude diagrams and luminosity
functions for nearby galaxies. For local group galaxies, we also include G750L
slitless spectroscopy to search for e.g., Carbon stars, late M giants and
stars. This survey will be useful to study the star formation histories,
chemical evolution, and distances to these galaxies. These data will be placed
immediately into the Hubble Data Archive.

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 9658

ACS Earth Flats

This program will obtain sequences of flat field images by observing the bright
Earth. Several UV filters from the interim calibration program {9564} require
additional exposures to obtain the required illumination. A few UV filters from
this program will be repeated to monitor for changes in the flat fields and to
verify the interim results. Since no streaks are observed in the UV, the
wavelength coverage is extended to longer wavelengths in order to explore the
severity of streaks in the flats from clouds in the FOV. We have added
for the HRC in the visible filters to verify the results derived from the
campaign and to explore the severity of streaks. We have also added
exposures on
WFC using the minimum exposure time and using filters which will not saturate
the brightest WFC pixel by more than 10 times the full well.

ACS 9667

ACS PSF Characterization

This proposal will characterize well-exposed PSFs in ACS. This includes
measuring the "Red Halo" in the HRC caused by CCD substrate translucency. The
off-spot HRC coronagraphic PSF will also be characterized. This program
does not
need to be repeated in later cycles unless PSFs in other filters are needed.

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 9699

POMS Test Proposal: WFII backup parallel archive proposal

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


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.

STIS 9706

STIS Pure Parallel Imaging Program: Cycle 10

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


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





FGS2R Transient Response Test Visit 04974S1 scheduled to be executed from
SMS 009/19:11:00Z – 19:29:03Z, Visit 04974S2 scheduled 009/21:51:24Z –
Test macros are planned to be executed via real-time commanding during
these visits.
The last 17 minutes will be recorded on the SSR engineering partition.

Successfully completed the Venus Observation OAT 008/11:00Z – 19:35Z with
String and the VEST. Installed, regression tested, and backed-out Venus
Marco. After the OAT part of the test was completed, the Venus macro was
and the command "XINERALH" to executed SPC List Exhaustion Safemode test
was sent.
The Venus Macro put the spacecraft in Software Sunpoint Safemode, as expected.

SpaceRef staff editor.