Status Report

NASA Hubble Space Telescope Daily Report # 3606

By SpaceRef Editor
May 10, 2004
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NASA Hubble Space Telescope Daily Report # 3606

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




ACS 9476

Galaxy Evolution in the Richest Clusters at z=0.8: the EDisCS Cluster

The study of distant cluster galaxies requires two key ingredients:
{1} deep high-resolution imaging, to constrain galaxy structure; and
{2} 8m-class spectroscopy, to measure stellar content, star-formation
rates, dynamics, and cluster membership. We will reach both conditions
with the addition of HST/ACS imaging to our suite of VLT {36 nights}
and NTT {20 nights} observations of 10 confirmed clusters at z~0.8,
drawn from the ESO Distant Cluster Survey {EDisCS}. The proposed
HST/ACS data will complement our existing optical/IR imaging and
spectroscopy with quantitative measures of cluster galaxy morphologies
{i.e. sizes and shapes, bulge-disk decompositions, asymmetry
parameters}, and with measurements of cluster masses via weak lensing.
Major advantages unique to the EDisCS project include: {i} uniform
selection of clusters; {ii} large enough sample sizes to characterize
the substantial cluster-to-cluster variation in galaxy populations;
{iii} large quantities of high quality data from 8m telescopes; {iv}
uniform measurements of morphologies, spectroscopic and photometric
redshifts, SEDs, star-formation/AGN activities, and internal
kinematics; {v} optical selection of clusters to complement the X-ray
selection of almost all high-z clusters in the ACS GTO programs; {vi}
forefront numerical simulations designed specifically to allow
physical interpretation of observed differences between the high-z and
local clusters.


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.


HST / Chandra Monitoring of a Dramatic Flare in the M87 Jet

As the nearest galaxy with an optical jet, M87 affords an unparalleled
opportunity to study extragalactic jet phenomena at the highest
resolution. During 2002, HST and Chandra monitoring of the M87 jet
have detected a dramatic flare in knot HST-1 located ~1" from the
nucleus. Its brightness has increased ten-fold in the optical band,
and continues to increase, and the X-rays show a similarly dramatic
outburst. In both bands this HST-1 now rivals the nucleus in
brightness. To our knowledge this is the first incidence of an optical
or X-ray outburst from a jet region which is spatially distinct from
the core source; this presents an unprecedented opportunity to study
the processes responsible for non-thermal variability and the X-ray
emission. We propose four epochs of HST/ACS monitoring during Cycle
12, as well as seven epochs of Chandra/ACIS observation {5ksec each}.
We also include a brief STIS observation that will be used with prior
STIS data to measure proper motions, and ACS polarimetry to map the
magnetic field structure. The results of this investigation are of key
importance not only for understanding the nature of the X-ray emission
of the M87 jet, but also for understanding flares in blazar jets,
which are highly variable, but where we have never before been able to
resolve the flaring region in the optical or X-rays. These
observations will allow us to test synchrotron emission models for the
X-ray outburst, constrain particle acceleration and loss timescales,
and study the jet dynamics associated with this flaring component.

ACS/WFC 9727

Exploration of the SN Ia Hubble Diagram at z > 1.2

In the spirit of a Treasury proposal, we propose to organize, and
deliver to the astronomical community, non-proprietary follow-up
observations of ~10 Type Ia supernovae at 1<z<1.7 that are expected to
be discovered in a Cycle 12 Treasury proposal. Together with the
currently available sample, this would provide a Hubble diagram with
over 20 SNe Ia in this redshift range, where it is possible to test
the current cosmological model in the epoch of deceleration: If z ~
0.5 SNe Ia are fainter due to evolution rather than an accelerating
expansion, they should continue to get fainter at even higher
redshifts. This size sample will show trends and outliers, and permit
a more rigorous treatment of the asymmetric amplification distribution
from gravitational lensing. This is a key redshift range for the
studies of dark energy that will be done with future surveys {and
future instruments now being designed}; this dataset will lay the
ground-work for these studies by establishing the simple properties of
the supernovae in this redshift range, including magnitudes, colors,
and timescales. If considered more appropriate, this proposal could be
treated as a part of a Treasury or Director’s Discretionary program,
since the data would be available to everybody immediately, and we
would welcome others who would want to work with us on it.

ACS/WFC 9766

The Globular Cluster Systems of Spiral Galaxies along the Hubble

While the globular cluster {GC} systems of ellipticals and ongoing
mergers have been relatively well-studied with HST, very little is
known about the GC systems of spirals besides the Milky Way and M31.
To constrain GC/galaxy formation models, especially where spirals are
the merger progenitors of ellipticals, it is crucial to understand
their GC properties. We propose to obtain ACS images of three edge-on
spirals, spanning the Hubble sequence, with Keck spectroscopic
follow-up. This will effectively double the number of well-studied
spiral systems. We will detect 100-200 GCs per galaxy, sufficient to
reveal GC subpopulations, their relative numbers, radial trends, and
dependences on Hubble type {e.g., a bulge vs. disk origin for red
GCs}. For half of our GCs we will be able to measure individual sizes.
By providing a much-needed comparative benchmark, these data will
allow researchers to better exploit the large existing HST database of
GCs in E/S0 galaxies.

ACS/WFC 9899

Geometrical Distance of NGC 2808 and NGC 6752

This is a proposal to establish a globular cluster distance scale of
unprecedented accuracy and reliability, with far-reaching impact on
the distance scales of cosmology. Our method is to compare internal
dispersion proper motions with ground-based determination of the
dispersion of the radial velocities {with time already allocated at
VLT}. The prospect is a geometrically based distance with an accuracy
of better than 2%. Results already in hand for M4 and 47 Tuc,
establish our ability to make such measurements of proper motions. Our
projects has two parts: {1} use archival observation for both epochs
when available, {2} The present proposal cover an external field of
NGC 2808 and give a second epoch for the cluster NGC6752. Thanks to
the ACS features, we will be able to extend the sample in just 2-4


The COSMOS 2-Degree ACS Survey

We will undertake a 2 square degree imaging survey {Cosmic Evolution
Survey — COSMOS} with ACS in the I {F814W} band of the VIMOS
equatorial field. This wide field survey is essential to understand
the interplay between Large Scale Structure {LSS} evolution and the
formation of galaxies, dark matter and AGNs and is the one region of
parameter space completely unexplored at present by HST. The
equatorial field was selected for its accessibility to all
ground-based telescopes and low IR background and because it will
eventually contain ~100, 000 galaxy spectra from the VLT-VIMOS
instrument. The imaging will detect over 2 million objects with I> 27
mag {AB, 10 sigma}, over 35, 000 Lyman Break Galaxies {LBGs} and
extremely red galaxies out to z ~ 5. COSMOS is the only HST project
specifically designed to probe the formation and evolution of
structures ranging from galaxies up to Coma-size clusters in the epoch
of peak galaxy, AGN, star and cluster formation {z ~0.5 to 3}. The
size of the largest structures necessitate the 2 degree field. Our
team is committed to the assembly of several public ancillary datasets
including the optical spectra, deep XMM and VLA imaging, ground-based
optical/IR imaging, UV imaging from GALEX and IR data from SIRTF.
Combining the full-spectrum multiwavelength imaging and spectroscopic
coverage with ACS sub-kpc resolution, COSMOS will be Hubble’s ultimate
legacy for understanding the evolution of both the visible and dark

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
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 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.

NIC2 9856

A near-IR imaging survey of submm galaxies with spectroscopic

Submillimeter {submm} surveys with SCUBA have identified a population
of obscured star-forming and active galaxies at high redshift. Our
recent spectroscopic campaigns with the Keck-10m telescope have
uncovered redshifts for 37 SCUBA galaxies. The wide redshift range of
the radio identified submm population {z=1-4} implies that many
varieties of sources driven by different physical processes may be
selected in a submm survey. We propose to use HST-NICMOS, ACS to
obtain 2-filter images of a sample of 15 SCUBA galaxies with redshifts
spanning z=0.8-3.5. Our goal is to understand what physical process
{major mergers?} drive their strong evolution and great luminosities,
and what the implications are for galaxy evolution models.

NIC3 9999

The COSMOS 2-Degree ACS Survey NICMOS Parallels

The COSMOS 2-Degree ACS Survey NICMOS Parallels. This program is a
companion to program 9822.

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.

WFPC2 10070

WFPC2 CYCLE 12 Supplemental Darks Part 2/3

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
investigated.) None



  • 1234-0 TDW Cross-support tracking (T77 CODE) @ 126/1951z
  • 1234-0 TDW Cross-support tracking (T77 CODE) @ 127/0217z

                           SCHEDULED     SUCCESSFUL    FAILURE TIMES
GSacq               09                           09
FGS REacq               06                           06
FHST Update            13                           13


SpaceRef staff editor.