Status Report

NASA Hubble Space Telescope Daily Report # 3698

By SpaceRef Editor
September 20, 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.

ACS/WFC 10121

The Core Dynamics of the Dense Globular Cluster NGC 6752

NGC 6752 is one of the best-studied dense globular clusters, and a
wide variety of intriguing and anomalous results have been obtained.
We propose ACS imaging of the core of this cluster. This will increase
the accuracy of our previous internal proper motion measurements by
almost an order of magnitude, providing an unprecedented probe of the
central potential. The data will also greatly increase the radial
extent of previous work on the binary frequency and luminosity
function of this cluster. Together, the data will provide a new level
of constraints on the dynamics of a dense globular cluster.


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.


Globular Cluster Systems of Giant, Post-Starburst Shell Ellipticals

Mergers seem to have played a major role in determining the shapes and
dynamics of elliptical galaxies. A few galactic mergers still occur
and offer valuable clues to past evolutionary processes. Young
globular clusters formed during mergers hold strong promise for
age-dating such events, besides helping shed light on the
cluster-formation process itself. With young globulars in ongoing
mergers and ~0.5 Gyr old remnants now well studied {NGC 4038/39, 3256,
7252, and 3921}, we propose to observe 4 bona fide ellipticals
featuring ripples, tidal tails as well as post-starburst spectra {E+A
galaxies: strong Balmer absorption}, which are obvious candidates for
having undergone a dissipated merger 1-4 Gyr ago. If the globulars
formed during mergers are formed with a normal IMF, they should still
be around in large numbers in intermediate-age systems. If that is
indeed the case, it would constitute strong evidence in favor of the
scenario in which metal-rich globulars in ‘normal’ ellipticals are
formed in merging events. We plan to use these ACS observations to {1}
measure high-accuracy {g-I error of 0.1 mag} colors for clusters as
faint as the peak of the luminosity function {LF} of old globulars,
{2} use these colors to separate first- and second-generation
clusters, and {3} determine the LFs of the two kinds of clusters down
to 1.5 mag past the LF peak for old globulars. Deep dithered g&I-band
images form a crucial part of our observing strategy. When combined
with previous HST studies of globulars in mergers, this study will
yield about a dozen globular cluster systems with age estimates,
enough to make meaningful statements about the influence of mergers in
creating "red”, metal-rich globulars in giant E’s and the evolution
of the specific frequency of globular clusters during galactic

NIC/NIC3 10226

The NICMOS Grism Parallel Survey

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
0.7<z<1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial–but poorly observed–redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

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.

NIC2 10176

Coronagraphic Survey for Giant Planets Around Nearby Young Stars

A systematic imaging search for extra-solar Jovian planets is now
possible thanks to recent progress in identifying "young stars near
Earth". For most of the proposed young {<~ 30 Myrs} and nearby {<~ 60
pc} targets, we can detect a few Jupiter-mass planets as close as a
few tens of AUs from the primary stars. This represents the first time
that potential analogs of our solar system – that is planetary systems
with giant planets having semi-major axes comparable to those of the
four giant planets of the Solar System – come within the grasp of
existing instrumentation. Our proposed targets have not been observed
for planets with the Hubble Space Telescope previously. Considering
the very successful earlier NICMOS observations of low mass brown
dwarfs and planetary disks among members of the TW Hydrae Association,
a fair fraction of our targets should also turn out to posses low mass
brown dwarfs, giant planets, or dusty planetary disks because our
targets are similar to {or even better than} the TW Hydrae stars in
terms of youth and proximity to Earth. Should HST time be awarded and
planetary mass candidates be found, proper motion follow-up of
candidate planets will be done with ground-based AOs.

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 9534: GS Acquisition (1,3,1) @ 261/21:45:29Z resulted in FL
backup (3,0,3) due to SSLE on FGS 1. Previous FHST Roll Delay Update
was successful with small axis errors. There was no FHST Map
scheduled after the GS Acquisition. The following GS acquisition
passed with no problem. Under investigation.

HSTAR 9535: GS Acquisition (3,1,3) @ 261/23:45:26Z failed to RGA
control due to SRLE on FGS 1 and FGS 3. Two FHST FM Updates scheduled
prior to the GS acquisition both succeeded and had a very low vehicle
error observed. Search Radius for GS acquisition was 55 arcsec.
Following GS acquisition was successful. FHST Map @ 261/23:53:14Z
showed errors of -12.874, -3.777 and -5.104 arcsec. Under

HSTAR 9536: GS Acquisition (3,1,3) @ 262/04:43:34Z succeeded after
failing multiple attempts at FL walkdown for SRLE on FGS 1.
Subsequent FHST Map @ 262/04:56:16Z had 3-axis (RSS) value
approximately 12.00 arcsec. Reference HSTAR 9535, had GS ID: Primary
FGS 0848300909, Secondary 0848300233. Under investigation.

HSTAR 9537: GS Acquisition (2,1,2) @ 262/11:13:11Z resulted in FL
backup (2,0,2)due to SSLE on FGS 1. GS Reacquisition (2,1,2) @
262/12:27:49Z will also result in FL backup (2,0,2). Under


1259-0 Battery 3 Capacity test ground limits @ 262/21:59z

                           SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS Gsacq                35                        34               See 
Hstar # 9535
FGS Reacq                19                        19
FHST Update              41                        41


SpaceRef staff editor.