Status Report

NASA Hubble Space Telescope Daily Report # 3697

By SpaceRef Editor
September 17, 2004
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




ACS/HRC 10182

Towards a Comprehensive Understanding of Type Ia Supernovae: The
Necessity of UV Observations

Type Ia supernovae {SNe Ia} are very important to many diverse areas
of astrophysics, from the chemical evolution of galaxies to
observational cosmology which led to the discovery of dark energy and
the accelerating Universe. However, the utility of SNe Ia as
cosmological probes depends on the degree of our understanding of SN
Ia physics, and various systematic effects such as cosmic chemical
evolution. At present, the progenitors of SNe Ia and the exact
explosion mechanisms are still poorly understood, as are evolutionary
effects on SN Ia peak luminosities. Since early-time UV spectra and
light curves of nearby SNe Ia can directly address these questions, we
propose an approach consisting of two observational components: {1}
Detailed studies of two very bright, young, nearby SNe Ia with HST UV
spectroscopy at 13 epochs within the first 1.5 months after discovery;
and {2} studies of correlations with luminosity for five somewhat more
distant Hubble-flow SNe Ia, for which relative luminosities can be
determined with precision, using 8 epochs of HST UV spectroscopy
and/or broad-band imaging. The HST data, along with extensive
ground-based optical to near-IR observations, will be analyzed with
state-of-the-art models to probe SN Ia explosion physics and constrain
the nature of the progenitors. The results will form the basis for the
next phase of precision cosmology measurements using SNe Ia, allowing
us to more fully capitalize on the substantial past {and future}
investments of time made with HST in observations of high-redshift SNe

ACS/HRC 10238

The nature of quasar host galaxies: combining ACS imaging and VLT
Integral Field Spectroscopy.

We propose to perform ACS/F606W imaging of a complete sample of 29
quasar host galaxies {0.08<z<0.34}. The spatial resolving power of the
ACS HRC, in combination with the acquisition of empirical PSFs and
advanced deconvolution techniques, will allow to study in detail
structures on scales of a few tens of parsecs, and to access the inner
regions of the host galaxies, even in the presence of bright nuclei.
We demonstrate that combining deep spectroscopy with high resolution
imaging in stable PSF conditions definitely constitutes the solution
to characterize the complex physical properties of quasar host
galaxies, from their outer regions to the inner 0.1 kpc, where most of
the information on the interplay between quasars and their hosts is
hidden. We propose to combine new ACS images with existing Integral
Field VLT Spectra. We will map the stellar and gas velocity fields in
2D, constrain the mass models, derive the radial host M/L ratios, map
and characterize the stellar populations and the ionization state of
the gas.

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.


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.


Star Clusters and Stellar Populations in M81

We propose a quick imaging survey of the nearby luminous spiral galaxy
M81with the ACS in F814W. After Andromeda, M81 is the nearest big
intermediate type spiral galaxy and is thus a primary candidate for
stellar population studies. At 3.8 Mpc, 1ACS WFC pixel is 1 pc. We
will cover the inner part of the galaxy where confusion is the
greatest problem in cluster studies, with 24 ACS fields. This survey
will provide the sample and spatial information necessary to study the
globular and open cluster systems of M81, spatial distribution,
metallicity, object size distribution, the GCLF, etc., in exquisite
detail especially when combined with our existing ground-based
multicolor imaging and planned spectroscopy.

ACS/WFC 10216

Co-evolution of spheroids and black holes

The masses of the giant black holes in galaxies are correlated with
the luminosities, masses, and velocity dispersions of their host
spheroids. This empirical connection of phenomena on widely different
scales {from sub-parsec to kiloparsec} suggests that the evolution of
a galaxy and its central black hole are closely linked. We propose to
test various unified formation models, by measuring the cosmic
evolution of the black hole/spheroid relations, back to z=0.37 {a
lookback time of 4 Gyrs}. We will obtain 1-orbit ACS images of a
sample of 20 Seyfert 1 galaxies, for which we already have extensive
new ground-based measures of the black hole masses and the stellar
velocity dispersions. HST resolution is required for accurate
measurement of the nonstellar AGN continuum, and the luminosity and
effective radius of the bulge of each host galaxy. This will complete
the set of observables needed to map the co-evolution of spheroids and
black-holes. The proposed sample is the minimum required to make the
first measure of the black hole mass/bulge correlation and of the
fundamental plane for active galaxies outside the local Universe.

ACS/WFC/NIC3 10340


Type Ia supernovae {SNe Ia} provide the only direct evidence for an
accelerating universe, an extraordinary result that needs the most
rigorous test. The case for cosmic acceleration rests on the
observation that SNe Ia at z = 0.5 are about 0.25 mag fainter than
they would be in a universe without acceleration. A powerful and
straightforward way to assess the reliability of the SN Ia measurement
and the conceptual framework of its interpretation is to look for
cosmic deceleration at z > 1. This would be a clear signature of a
mixed dark-matter and dark-energy universe. Systematic errors in the
SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia
peak luminosity would not show this change of sign. We have obtained a
toehold on this putative “epoch of deceleration” with SN 1997ff at z
= 1.7, and 3 more at z > 1 from our Cycle 11 program, all found and
followed by HST. However, this is too important a test to rest on just
a few objects, anyone of which could be subject to a lensed
line-of-sight or misidentification. Here we propose to extend our
measurement with observations of twelve SNe Ia in the range 1.0 < z <
1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be
discovered as a byproduct from proposed Treasury and DD programs.
These objects will provide a much firmer foundation for a conclusion
that touches on important questions of fundamental physics.

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.

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 9533: FHST Roll Delay Update (U1,2RD) @ 260/22:06:44Z failed
with Error Box results indicating "1FAILED" for mnemonics QEBSTFG0,
QEBSTFG1, and QEBSTFG2. Subsequent GS Acquisition (1,2,2) @
260/22:12:08Z was successful. Under investigation.


17274-0 Off-line AA and +CC SPAs @ 260/12:58z

17276-0 Turn FGS3 Stop Flag Limit on @ 260/19:46z


                           SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS Gsacq                14                       14
FGS Reacq                 03                       03
FHST Update              16                       15              See Hstar 
# 9533


Successfully completed EPS reconfiguration to bring the +B SPA back
online and to take the -AA and +CC SPAs offline in the PCU-R and 486
FSW (TRSWCC table and Macros). Commanding was completed during the
planned uplink opportunity at 260/12:58Z. (OR 17274 with attached
IP-063 and IP-067 scripts). Following the uplink, EPS SEs monitored
the power system operations from the MOR for two orbits to verify
nominal operation of TRSWCC (-AA and +CC SPA Trim Relay disconnected
and proper order of TRSWCC commanded relay openings upon Trickle
Charge initiation). Immediately following the reconfiguration, the
batteries were in Trickle Charge during the first and second orbits
for 16 minutes and 26 minutes, respectively. EPS SEs continued to
closely monitor the power system performance, especially battery
temperatures and pressures and to assess the effects of the

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