Status Report

NASA Hubble Space Telescope Status Report # 3701

By SpaceRef Editor
September 23, 2004
Filed under , ,

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 10253

A UV Survey of Quiescent Black Holes and Neutron Stars

Existing STIS observations of quiescent Galactic black hole and
neutron star binaries suggest a striking difference between them. The
spectra of black holes appear to drop off steeply in the near-UV,
whereas those of neutron stars continue to rise, at least down to
1700A. This difference has been interpreted in terms of advective
accretion models, and may indicate a fundamental signature of the two
types of object. The existing data do not include enough objects to
form a representative sample, however. We will exploit the faint
source sensitivity of ACS to perform a survey of the UV spectral
shapes across a larger sample containing both black holes and neutron
stars. This survey will test the assertion that their UV spectra are
strikingly different; allow modelling of the broad band spectral
energy distribution; test for variability in the UV flux; and identify
suitable targets for subsequent spectroscopic follow-up..


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 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 10217

The ACS Fornax Cluster Survey

The two rich clusters nearest to the Milky Way, and the only large
collections of early-type galaxies within ~ 25 Mpc, are the Virgo and
Fornax Clusters. We propose to exploit the exceptional imaging
capabilities of the ACS/WFC to carry out the most comprehensive
imaging survey to date of early-type galaxies in Fornax: the ACS
Fornax Cluster Survey. Deep ACS/WFC images — in the F475W {g’} and
F850LP {z’} bands — will be acquired for 44 E, S0, dE, dE, N and dS0
cluster members. In Cycle 11, we initiated a similar program targeting
early-type galaxies in the Virgo Cluster {the ACS Virgo Cluster
Survey; GO-9401}. Our proposed survey of Fornax would yield an
extraordinary dataset which would complement that already in hand for
Virgo, and allow a definitive study of the role played by environment
in the structure, formation and evolution of early-type galaxies and
their globular cluster systems, nuclei, stellar populations, dust
content, nuclear morphologies and merger histories. It would also be a
community resource for years to come and, together with the ACS Virgo
Cluster Survey, constitute one of the lasting legacies of HST.

ACS/WFC 10342

Hubble Heritage Observations of NGC 1300

Observing NGC1300 in four bands for Hubble Heritage project.


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.

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

WFPC2 10080

Wavelength Stability of Narrow Band and Linear Ramp Filters

Verify the mapping of wavelength as a function of CCD position on
LRFs; check for changes in central wavelengths of narrow band filters.

WFPC2 10360


This calibration proposal is the Cycle 13 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a
monitor for possible buildup of contaminants on the CCD windows.


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

HSTAR 9545: At AOS at 267/02:26:30Z, HST was in FL backup on FGS 3
only, GS Acquisition (3,1,1) @ 267/02:16:55Z did not acquire on FGS 1.
GS Reacquisition @ 267/03:51:55Z also ended up in FL backup on FGS 3
only. Further information will be available after engineering
recorder dump. Under investigation.

17277-0 HGA Offset Test @ 267/0824z


                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS Gsacq                 08                       08
FGS Reacq                 08                       08
FHST Update              16                        16


HST VEST Testing of Safemode Recovery Procedures for HWSP scheduled
267/10:00Z – 22:00Z with GDOC, HITT, SE, and VEST using CCS "D" String
with CCS Release xx (intentionally removed) and PRD xx (intentionally
removed). The purpose of this testing is to verify Safemode Recovery
Procedures in the event of an HST safing event in to HWSP.

SpaceRef staff editor.