NASA Hubble Space Telescope Daily Report #3924

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT       # 3924

PERIOD COVERED: UT August 15, 2005 (DOY 227)

OBSERVATIONS SCHEDULED

ACS/HRC 10377

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth
with the HRC and WFC. These observations will be used to verify the
accuracy of the flats currently used by the pipeline and will provide
a comparison with flats derived via other techniques: L-flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronagraphic
monitoring is required to assess the changing position of the spots.

ACS/HRC/NIC2 10244

Coronagraphic imaging of Eta Corvus: a newly discovered debris disk at
18 pc

Debris disks are one of the final stages in the evolution of planetary
systems. High resolution imaging of debris disks has been instrumental
to our understanding of the status of planet formation in these
systems. The detection of clumps and asymmetries has even led to the
detection of unseen planets. However, just six resolved disks exist in
the literature. Eta Crv is now the seventh debris disk confirmed with
imaging, and was discovered in a recent sub-mm survey of nearby stars.
Its proximity {18 pc} and similarity to Beta Pic, one of the “big
four” Vega-type disks, makes it an excellent candidate for a high
resolution coronagraphic study of its disk structure. Modeling of this
structure at many wavelengths will set hard constraints on its unseen
planetary system and the distribution of particles from micron to
kilometer in size, thus significantly extending our understanding of
the planet formation processes in debris disks

ACS/HRC/NIC3 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
Ia.

ACS/HRC/WFC 10389

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 program will be
for the entire lifetime of ACS.

ACS/WFC 10349

A Uniform Study of Globular Cluster X-ray Sources: the Keys to Cluster
Dynamical Evolution

We propose to extend our ongoing studies of the dynamical evolution of
globular clusters by observing their populations of low-luminosity
X-ray sources. Many of these sources are binary systems {or have
evolved from them} and hold the key to the cluster’s dynamical
evolution. We propose observations of a variety of clusters with
widely different physical properties such as central concentration,
cluster size and mass, which are all key ingredients in the formation
and evolution of binaries. To make this study as uniform as possible,
the clusters will be observed to the same limiting luminosity. Joint
observations with HST will allow for definitive source identification.

ACS/WFC 10588

The Host Galaxies of Post-Starburst Quasars

We propose to use ACS to conduct a snapshot imaging survey of
post-starburst quasars now being discovered in signficant numbers by
the Sloan Digital Sky Survey. Post-starburst quasars are broad-lined
AGN that also possess Balmer jumps and high-n Balmer absorption lines
indicative of luminous stellar populations on order of 100 Myr old.
These objects, representing a few percent of the z < 0.5 quasar population, may be an evolutionary stage in the transition of ultraluminous infrared galaxies into normal quasars, or a type of galaxy interaction that triggers both star formation and nuclear activity. These sources may also illustrate how black hole mass/bulge mass correlations arise. Ground-based imaging of individual poststarburst quasars has revealed merger remnants, binary systems, and single point sources. Our ACS snapshots will enable us to determine morphologies and binary structure on sub-arcsecond scales {surely present in the sample and impossible to do without HST}, as well as basic host galaxy properties. We will be looking for relationships among morphology, particularly separation of double nuclei, the starburst age, the quasar black hole mass and accretion rate, that will lead to an understanding of the triggering activity and mutual evolution. This project will bring quantitative data and statistics to the previously fuzzy and anecdotal topic of the "AGN-starburst connection" and help test the idea that post-starburst quasars are an early evolutionary stage of normal quasars.

ACS/WFC/NIC3 10405

Probing the establishment of galaxy morphologies in the best-studied
high-redshift structure

We propose deep ACS I-band imaging of arguably the best-studied
high-redshift proto-cluster environment, a high-contrast structure in
the SSA22 field at z=3.1. Our on-going study of this region has
identified over 400 probable members of this structure across a
16-arcmin-square field, selected through narrow-band Lyman-alpha
emission, Lyman-break photometric criteria and far-infrared/radio
emission. Our proposed high-resolution imaging of galaxies in the
z=3.1 structure and in the nearby field, will provide morphological
information on galaxies over nearly two-orders of magnitude in local
density at this early epoch. This will allow us for the first time to
test whether galaxy morphology is defined at the formation of a galaxy
or reflects processes acting on it during its lifetime.

FGS 10610

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric
elements {perturbation orbit semi-major axis and inclination} of
extra-solar planets orbiting six stars. These companions were
originally detected by radial velocity techniques. We have
demonstrated that FGS astrometry of even a short segment of reflex
motion, when combined with extensive radial velocity information, can
yield useful inclination information {McArthur et al. 2004}, allowing
us to determine companion masses. Extrasolar planet masses assist in
two ongoing research frontiers. First, they provide useful boundary
conditions for models of planetary formation and evolution of
planetary systems. Second, knowing that a star in fact has a plantary
mass companion, increases the value of that system to future
extrasolar planet observation missions such as SIM PlanetQuest, TPF,
and GAIA.

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.

NIC1/Spacecraft 10382

NICMOS Focus Stability

The purpose of this activity is to determine the best focus. This
program will execute in one month intervals starting about 1 month
after the last execution of proposal 9994 {the previous focus
monitoring program}. The program starts with a focus sweep using only
the NIC1 camera {visit 11}. The following observation is with the NIC2
camera {visit 12} after about 45 days. This pattern is repeated
throughout the period except for Feb 15 where also the NIC3 camera is
used. In total this will result in 9 orbits. Notice that VISIT #1 #2
refers to visits for #1 sequential visit number for a given camera #2
camera in question visit 32 is therefore the third visit for camera 2.

WFPC2 10359

WFPC2 CYCLE 13 Standard Darks

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

                          SCHEDULED     SUCCESSFUL 
 FGS Gsacq               11                      11 
 FGS Reacq               08                       08 
 FHST Update             10                      10 

COMPLETED OPS NOTES: (None)

SIGNIFICANT