Status Report

NASA Hubble Space Telescope Daily Report # 3480

By SpaceRef Editor
October 31, 2003
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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<z<2. This
redshift range corresponds to the epoch of peak galaxy formation. In this
proposal we request 40 orbits of ACS imaging to determine the morphologies of
100-120 candidate early-type galaxies with known redshifts in our survey
We seek to determine if these systems are indeed elliptical galaxies and to
their morphological states to their spectroscopically determined ages, recent
star-formation histories, and to the evolving global stellar mass function at
the peak epoch of galaxy assembly.

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
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 9835

Shooting Stars: Looking for Direct Evidence of Massive Central Black Holes in
Globular Clusters

We propose to make observations that directly test the proposition that
clusters contain massive black holes. Our targets are the bulge globular
clusters NGC 6388 and NGC 6441. These are probably among the most massive
in the
galaxy, but are understudied compared to more familiar objects such as M15. Our
analysis suggests that these two clusters are the most likely to show
unambiguous evidence for a central massive black hole if such things exist in
globular clusters. The observations proposed will give us the first thorough
kinematic and photometric studies of these two clusters. The combination of the
two epochs will give us proper motions good to of order 6 km/s. In addition,
they will provide us with the first good, deep, color-magnitude diagrams for
these clusters. These diagrams will be used to investigate the make up of the
stellar population in the clusters, to more firmly establish their distances,
ages, and metallicities, and to search for a binary sequence.


CCD Daily Monitor

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.

FGS 9888

Trigonometric Calibration of the Period- Luminosity Relations for Fundamental
and First-Overtone Galactic Cepheids

Cepheids are the primary distance indicators for the extragalactic distance
scale and the Hubble constant. The Hubble Constant Key Project set the
zero-point for their Cepheid distance scale by adopting a distance to the LMC,
averaged over a variety of techniques. However, different methods give an LMC
distance modulus ranging from 18.1 to 18.8, and the uncertainty in the Cepheid
zero-point is now the largest contributor to the error budget for H_0.
the low metallicity of the LMC raises additional concerns, since the PL
probably depends on metallicity. The zero-point can be determined from
parallaxes of Galactic Cepheids out to several hundred parsecs, but with a
typical parallax error of 0.5-1 mas, the Hipparcos error bars are uncomfortably
large for this demanding application. By contrast, HST’s FGS1R interferometer
can achieve astrometric accuracy of 0.2 mas. We propose to use FGS1R to
determine trigonometric parallaxes for a sample of 9 nearby Cepheids, including
both fundamental {F} and first-overtone {FO} pulsators. We show that the
improvement in the PL relations for F and FO Cepheids will be dramatic. We will
determine the PL slopes from our nearby solar- metallicity sample alone,
recourse to nearby galaxies and the issue of [Fe/H] dependence. The zero-point
will be determined robustly to about 0.05 mag, based on accurate, purely
geometrical measurements. All of this can be achieved in the next few years
HST, without having to wait for the technically demanding and risky SIM and
missions well into the next decade.

FGS1R 9408

Calibrating the Mass-Luminosity Relation at the End of the Main Sequence

We propose to use HST-FGS1R to calibrate the mass-luminosity relation {MLR} for
stars less massive than 0.2 Msun, with special emphasis on objects near the
stellar/brown dwarf border. Our goals are to determine M_V values to 0.05
magnitude, masses to 5 than double the number of objects with masses determined
to be less than 0.20 Msun. This program uses the combination of HST-FGS3/FGS1R
at optical wavelengths and ground-based infrared interferometry to examine
nearby, subarcsecond binary systems. The high precision measurements with
HST-FGS3/FGS1R {to 1 mas in the separations} for these faint targets {V =
10–15} simply cannot be equaled by any ground based technique. As a result of
these measurements, we are deriving high quality luminosities and masses
for the
components in the observed systems, and characterizing their spectral energy
distributions from 0.5 to 2.2 Mum. Several of the objects included have M < 0.1
Msun, placing them at the very end of the stellar main sequence. Three of the
targets are brown dwarf candidates, including the current low mass record
holder, GJ 1245C, with a mass of 0.062 +/- 0.004 Msun. The payoff of this
proposal is high because all 10 of the systems selected have already been
resolved with HST- FGS3/FGS1R during Cycles 5–10 and contain most of the
reddest objects for which masses can be determined.

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
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
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

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration – CR Persistence Part 3

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. 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
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

STIS/CCD 10000

STIS Pure Parallel Imaging Program: Cycle 12

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

STIS/CCD 10017

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD.

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

STIS/CCD 10022

STIS CCD Hot Pixel Annealing Cycle 12

The effectiveness of the CCD hot pixel annealing process is assessed by
measuring the dark current behavior before and after annealing and by searching
for any window contamination effects. In addition CTE performance is
examined by
looking for traps in a low signal level flat. Follows on from proposal 9612.

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 pixels.

WFPC2 10082

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans

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.


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

HSTAR 9183: GS Acquisition (2,1,2) @ 304/06:15:47Z failed to Gyro hold due to
SRLE on FGS 1 and 2. Previous FHST FM Update passed
with errors of -15.22, -1.063, and -11.415 arcsec. STIS 710 Status Buffer
message was due
to this failure. Under investigation.

17058-0 – Genslew for proposal 9987 – slot 8 @ 303/1926z
17059-0 – Genslew for proposal 9987 – slot 9 @ 303/1930z


                         SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              8                         7              304/0616z 
(HSTAR 9183)
FGS REacq              6                         6
FHST Update            19                       19


SpaceRef staff editor.