Status Report

NASA Hubble Space Telescope Daily Report # 3645

By SpaceRef Editor
July 6, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science





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.


The Evolution and Assembly of Galactic Disks: Integrated studies of
mass, stars and gas in the Extended Groth Strip

This project is a 126-orbit imaging survey in F606W/F814W ACS to
measure the evolution of galaxy disks from redshift z = 1.4 to the
present. By combining HST imaging with existing observations in the
Extended Groth Strip, we can for the first time simultaneously
determine the mass in dark matter that underlies disks, the mass in
stars within those disks, and the rate of formation of new stars from
gas in the disks, for samples of >1, 000 objects. ACS observations are
critical for this work, both for reliable identifications of disks and
for determining their sizes and inclinations. Combining these data
with the kinematics measured from high-resolution Keck DEIMOS spectra
will give dynamical masses that include dark matter. Stellar masses
can be measured separately using ground-based BRIK and Spitzer IRAC
GTO data, while cross-calibrated star formation rates will come from
DEEP2 spectra, GALEX, and Spitzer/MIPS. The field chosen is the only
one where all multiwavelength data needed will be available in the
near term. These data will show how the fundamental properties of
disks {luminosity, rotation speed, scale length} and their scaling
relations have evolved since z~1, and also will measure the build-up
of stellar disks directly, providing fundamental tests of disk
formation and evolution. In addition to the above study of disk
galaxies, the data will also be used to measure the evolution of
red-sequence galaxies and their associated stellar populations. ACS
images will yield the number of red-sequence galaxies versus time,
together with their total associated stellar mass. ACS images are
crucial to classify red-sequence galaxies into normal E/S0s versus
peculiar types and to measure radii, which will complete the suite of
fundamental structural parameters needed to study evolution. We will
measure the zeropoints of major scaling laws {Fundamental Plane,
radius versus sigma}, as well as evolution in characteristic
quantities such as L*, v*, and r*. Stellar population ages will be
estimated from high-resolution Keck DEIMOS spectra and compared to SED
evolution measured from GALEX, HST, Spitzer, and ground-based colors.
Important for both disk and red-galaxy programs are parallel exposures
to be taken with both NIC3 {J and H} and WFPC2 {B}. These are arranged
so that ACS, WFPC2, and NIC3 all overlap where possible , providing a
rich data set of galaxies imaged with all three HST cameras from B to
H. These data will be used to measure restframe visible morphologies
and UV star-formation rates for galaxies near the edge of the survey,
to discover and count EROs below the Keck spectroscopic limit of R =
24, and to provide an improved database of photometric redshifts for
galaxies in the overlap regions.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

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.


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.

STIS/CCD 10018

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 10020

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.


The Properties of Highly Ionized High Velocity Gas in the Distant
Galactic Corona and Local Group

We propose to observe two bright AGNs {NGC7469 and Mrk 335} with the
E140M grating of STIS to study the properties of highly ionized high
velocity O VI absorption systems associated with the Magellanic Stream
and several Local Group clouds. Unlike most high velocity cloud
studies, we know that these absorbers are located at large distances
from the Sun. The observations will allow us to perform detailed
studies of the ionization properties of the O VI absorbers and
discriminate between competing models for the production of the highly
ionized gas. We will analyze the component velocity structure of the
absorption to quantify the relationship of the highly ionized gas and
the neutral gas in this region of the sky, and determine if the
properties of the high velocity gas are consistent with an origin in
interfaces between warm clouds and a low-density hot {T > 10^6 K}
Galactic corona or Local Group medium. The results of this
investigation are directly relevant to studies of high velocity
clouds, the production of hot gas associated with galaxies, the
intergalactic medium, and the formation and evolution of galaxies.
Secondary science programs that will be undertaken with the proposed
observations include a study of the Galactic halo, analysis of the
intergalactic absorption along the sight lines, and an investigation
of the intrinsic AGN absorption in NGC 7469.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

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 9459: GS Acquisition (2,3,2) @ 182/13:22:35Z resulted in FL
backup (2,0,2) due to SRLE on FGS 2. Prior GS Acquisition (1,3,1),
scheduled @ 182/12:53:28Z, was successful. FHST Map @ 182/14:05:30Z
showed vehicle errors of 9.219, -6.061, and -5.704 arcsec.
Subsequent GS Reacquisitions @ 182/14:26:58Z, 17:38:58Z, 19:14:57Z,
and 20:50:56Z resulted in FL backup. Under investigation.

HSTAR 9460: GS Reacquisition (2,3,2) @ 182/19:14:57Z failed due to
SSLE on FGS. GS Reacquisition @ 182/20:50:56Z failed to Gyro hold.
GS Acquisition (2,3,2) resulted in FL backup. Under investigation.



                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                06                           06
REacq                12                           10 
182/19:14:57z,  182/20:50:56z
FHST Update              05                          05


Battery 5 discharge began @ 181/11:03Z with entry into orbit night.
Discharge at the high rate continued until 181/20:17Z, where Battery 5
Voltage dropped to 26.23 Volts and the FSW ACR autonomously switched
to the low rate, as planned.

SpaceRef staff editor.