Status Report

NASA Hubble Space Telescope Daily Report # 3848

By SpaceRef Editor
April 29, 2005
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT        # 3848



ACS/HRC 10199

The Most Massive Galaxies in the Universe: Double Trouble?

We are proposing an HST snapshot survey of 70 objects with velocity
dispersion larger than 350 km/s, selected from the Sloan Digital Sky
Survey. Potentially this sample contains the most massive galaxies in
the Universe. Some of these objects may be superpositions; HST imaging
is the key to determining if they are single and massive or if they
are two objects in projection. The objects which HST imaging shows to
be single objects are interesting because they potentially harbor the
most massive black holes, and because their existence places strong
constraints on galaxy formation models. When combined with ground
based data already in hand, the objects which HST imaging shows are
superpositions provide valuable information about interaction rates of
early- type galaxies as well as their dust content. They also
constrain the allowed parameter space for models of binary
gravitational lenses {such models are currently invoked to explain
discrepancies in the distribution of lensed image flux ratios and

ACS/HRC 10255

A Never Before Explored Phase Space: Resolving Close White Dwarf / Red
Dwarf Binaries

We propose an ACS Snapshot imaging survey to resolve a well-defined
sample of highly probable white dwarf plus red dwarf close binaries.
These candidates were selected from a search for white dwarfs with
infrared excess from the 2MASS database. They represent unresolved
systems {separations less than approximately 2″ in the 2MASS images}
and are distributed over the whole sky. Our HST+ACS observations will
be sensitive to a separation range {1-20 AU} never before probed by
any means. The proposed study will be the first empirical test of
binary star parameters in the post-AGB phase, and cannot be
accomplished from the ground. By resolving as few as 20 of our ~100
targets with HST, we will be able to characterize the distribution of
orbital semi- major axes and secondary star masses.


SAINTS – Supernova 1987A INTensive Survey

SAINTS is a program to observe SN 1987A, the brightest supernova in
383 years, as it transforms into supernova remnant {SNR} 1987A, the
youngest supernova remnant. HST is the unique and perfect match in
scale and in field for spatially-resolved observations of SN 1987A.
Rapid changes are taking place in a violent encounter between the
fastest-moving debris and the circumstellar ring. This one-time-only
event, leading to suddenly appearing hotspots and new emission that
can reveal previously hidden gas, is powered by shocks that can be
studied simultaneously with HST and with Chandra to great advantage.
Both the optical and X-ray flux from the ring are rising rapidly so
prompt observations are needed in Cycle 13. Our previous observations
reveal a remarkable reverse shock moving upstream through the
expanding debris. The reverse shock provides a powerful tool for
dissecting the radial structure of the vanished star. The debris from
the explosion itself, still excited by radioactivity, is now well
resolved by ACS and seen to be aspherical, providing direct clues to
the mechanism of the explosion. Many questions about SN 1987A remain
unanswered. SAINTS is a comprehensive attempt to use HST to establish
the facts of SN 1987A, help to answer interesting questions, and to
observe the birth of SNR 1987A.


ACS CCDs daily monitor – Cycle 13 – Part 2

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS.


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

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.

NIC3 10337

The COSMOS 2-Degree ACS Survey NICMOS Parallels

The COSMOS 2-Degree ACS Survey NICMOS Parallels. This program is a
companion to program 10092.


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

HSTAR 9790:  GSAcq(2,3,2) returns to SSM control @ 113/22:42:13z. OTA
SE review of PTAS processing reveals GSAcq(2,3,2) at 113/22:42:13
required two attempts to successfully acquire. It reached Fine Lock on
both FGS’s at 22:46:44 and returned to SSM control at 22:47:42. It
successfully achieved fine lock at 22:48:38.

HSTAR 9791: ReAcq(2,3,3) requires multiple entries into CT to achieve
DataValid @ 110/00:18:30z. OTA SE review of the PTAS processing found
that the ReAcq(2,3,3) at 110/00:18:30 required 2 CT entries on FGS2
before achieving CT-DV. The ReAcq was successful and no science impact
should have been seen.

17430-0 Genslew for Proposal 10263  Slot # 6 @ 117/14:51z


                            SCHEDULED     SUCCESSFUL    FAILURE TIMES 
 FGS Gsacq                 12                       12 
 Reacq                  05                       05 

FHST Update               16                        16 LOSS of LOCK


SpaceRef staff editor.