Daily #4013

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4013

PERIOD COVERED: UT December 21, 2005 (DOY 355)

OBSERVATIONS SCHEDULED

ACS/HRC/WFC 10729

ACS CCDs daily monitor

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. Changes from cycle 13:- The default
gain for WFC is 2 e-/DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period Oct, 2 2005- May, 29-2006. The
second half of the program has a different proposal number: 10758.

ACS/WFC 10497

Cepheid Calibrations of the Luminosity of Two Reliable Type Ia
Supernovae and a Re- determination of the Hubble Constant

We propose to determine the luminosity of two type Ia supernovae {SNe
Ia}, 1995al in NGC 3021 and SN 2002fk in NGC 1309, by observing
Cepheids in their spiral hosts. Modern CCD photometry yields an
extremely tight Hubble diagram for SNe Ia with a precisely determined
intercept {i.e., Delta H_0/H_0}. Yet, the measurement of the true
Hubble constant via SNe Ia is limited by the calibration derived from
problematic and unreliable SN data. Most of the SNe Ia calibrated by
HST to date are significantly compromised by the systematics of
photographic photometry, high reddening and SN peculiarity, and by the
photometric anomolies associated with WFPC2. The extended reach of ACS
now provides opportunities to more reliably calibrate SNe Ia and H_0.
Our Cepheid calibration of a reliable SN Ia dataset, SN 1994ae, using
ACS in Cycle 11 resulted in a 15% increase in H_0 from the value
derived by the HST SN Ia Calibration Program. Yet, there remains a
terribly small sample of reliable SN Ia data sets on which to base
such a crucial cosmological result. SN 1995al and SN 2002fk are two of
the best observed SNe Ia both with little reddening. They provide two
opportunities to use ACS for placing the calibration of H_0 via SN Ia
on firmer footing and potentially improve its precision.

ACS/WFC 10582

Probing The Galaxy-wide Globular Cluster - Low Mass X-ray Binary
Connection in Early-type Galaxies

The combination of high-resolution imaging from Hubble {HST} and
Chandra {CXO} has completely revolutionized our understanding of
extragalactic low-mass X-ray binaries {LMXBs} and globular clusters
{GCs}; however, studies have been limited by short X-ray exposures and
relatively small fields. NGC 4697 amd NGC 4365 are relatively simple
elliptical galaxies in the X- ray that will have deep CXO
observations. We propose ACS observations in six flanking fields per
galaxy to provide a study of the GC-LMXB connection in normal
early-type galaxies with unprecedented depth, spatial resolution and
areal coverage. Combined with existing central field observations, we
will detect ~900 and ~2700 GCs GCs in most of NGC 4697 and all of NGC
4365. These two galaxies will have the greatest number of detected
GC-LMXBs to date {~70 & 120}. We will measure the fraction of LMXBs
found in GCs, and the fraction of GCs which contain LMXBs, as a
function of X-ray luminosity, galactocentric distance, color, GC
half-light radius, and local GC specific frequency. We will test
existing models of GC formation/evolution and LMXB
formation/evolution. Using the radial profile of optical light, GCs,
and LMXBS, we will determine the percentage of field LMXBs which may
have originated in GCs.

ACS/WFC 10592

An ACS Survey of a Complete Sample of Luminous Infrared Galaxies in
the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
`luminous infrared galaxies' {LIRGs} are primarily interacting or
merging disk galaxies undergoing enhanced star formation and Active
Galactic Nuclei {AGN} activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
ACS/WFC imaging of a complete sample of 88 L_IR 10^11.4 L_sun
luminous infrared galaxies in the IRAS Revised Bright Galaxy Sample
{RBGS: i.e., 60 micron flux density 5.24 Jy}. This sample is ideal
not only in its completeness and sample size, but also in the
proximity and brightness of the galaxies. The superb sensitivity,
resolution, and field of view of ACS/WFC on HST enables a unique
opportunity to study the detailed structure of galaxies that sample
all stages of the merger process. Imaging will be done with the F439W
and F814W filters {B and I-band} to examine as a function of both
luminosity and merger state {i} the evidence at optical wavelengths of
star formation and AGN activity and the manner in which instabilities
{bars and bridges} in the galaxies may funnel material to these active
regions, {ii} the relationship between star formation and AGN
activity, and {iii} the structural properties {AGN, bulge, and disk
components} and fundamental parameters {effective radius and surface
brightness} of LIRGs and their similarity with putative evolutionary
byproducts {elliptical, S0 and classical AGN host galaxies}. This HST
survey will also bridge the wavelength gap between a Spitzer imaging
survey {covering seven bands in the 3.6-160 micron range} and a GALEX
UV imaging survey of these galaxies, but will resolve complexes of
star clusters and multiple nuclei at resolutions well beyond the
capabilities of either Spitzer or GALEX. The combined datasets will
result in the most comprehensive multiwavelength study of interacting
and merging galaxies to date.

FGS 10612

Binary Stars in Cyg OB2: Relics of Massive Star Formation in a
Super-Star Cluster

We propose to make a high angular resolution SNAP survey of the
massive stars in the nearby, super-star cluster Cyg OB2. We will use
FGS1r TRANS mode observations to search for astrometric companions in
the separation range of 0.01 to 1.00 arcsec and in the magnitude
difference range smaller than 4 magnitudes. The observations will test
the idea that the formation of very massive stars involves mergers and
the presence of nearby companions. Discovery of companions to massive
stars in this relatively nearby complex will provide guidance in the
interpretation of apparently supermassive stars in distant locations.
The search for companions will also be important for verification of
fundamental parameters derived from spectroscopy, adjustments to main
sequence fitting and distance estimations, determining third light
contributions of eclipsing binaries, identifying wide colliding wind
binaries, studying the relationship between orbital and spin angular
momentum, and discovering binaries amenable to future mass
determinations. The massive star environment in Cyg OB2 may be similar
to the kinds found in the earliest epoch of star formation, so that a
study of the role of binaries in Cyg OB2 will help us understand the
formation processes of the first stars in the Universe.

FGS 10757

Monitoring FGS1r's Interferometric Response as a Function of Spectral
Color

This proposal obtains reference point source Transfer Functions
{S-Curves} for FGS1r through the F583W filter and the F5ND attenuator
at the center position of the FGS1r FOV for a variety of stars of
different spectral types. These Transfer Functions are needed to
support the analysis of GO science data for the study of close and
wide binary star systems and for determining the angular size and
shape of extended sources. This proposal observes stars that have been
observed in previous cycles to monitor the long term evolution of the
FGS1r S-curves. This proposal also {1} monitors the FGS1r Lateral
Color response {using stars Latcol-A and Latcol-B}, {2} calibrates the
"Pos/Trans" bias of a star's position as determined from Transfer mode
and Position mode observations, and {3} calibrates the shift of a
star's centroid when observed with F5ND relative to that when observed
with F583W.

NIC2 10527

Imaging Scattered Light from Debris Disks Discovered by the Spitzer
Space Telescope Around 20 Sun-like Stars

We propose to use the high contrast capability of the NICMOS
coronagraph to image a sample of newly discovered circumstellar disks
associated with sun-like stars. These systems were identified by their
strong thermal infrared emission with the Spitzer Space Telescope as
part of the Spitzer Legacy Science program titled, "The Formation and
Evolution of Planetary Systems {FEPS}." Modelling of the thermal
excess emission in the form of spectral energy distributions alone
cannot distinguish between narrowly confined high opacity disks and
broadly distributed, low opacity disks. However, our proposed NICMOS
observations can, by imaging the light scattered from this material.
Even non- detections will place severe constraints on the disk
geometry, ruling out models with high optical depth. Unlike previous
disk imaging programs, our program contains a well defined sample of
solar mass stars covering a range of ages from ~10Myrs to a few Gyrs,
allowing us to study the evolution of disks from primordial to debris
for the first time. These results will greatly improve our
understanding of debris disks around Sun- like stars at stellar ages
nearly 10x older than any previous investigation. Thus we will have
fit a crucial piece into the puzzle concerning the formation and
evolution of our own solar system.

NIC3/ACS/WFC 10504

Characterizing the Sources Responsible for Cosmic Reionization

Our group has demonstrated the role that massive clusters, acting as
powerful cosmic lenses, can play in constraining the abundance and
properties of low-luminosity star-forming sources beyond z~6; such
sources are thought to be responsible for ending cosmic reionization.
The large magnification possible in the critical regions of
well-constrained clusters brings sources into view that lie at or
beyond the limits of conventional exposures such as the UDF, as well
as those in imaging surveys being undertaken with IRAC onboard
Spitzer. We have shown that the combination of HST and Spitzer is
particularly effective in delivering the physical properties of these
distant sources, constraining their mass, age and past star formation
history. Indirectly, we therefore gain a valuable glimpse to yet
earlier epochs. Recognizing the result {and limitations} of the UDF
exposure, we propose a systematic search through 6 lensing clusters
with ACS and NICMOS for further z~6-7 sources in conjunction with
existing deep IRAC data. Our survey will mitigate cosmic variance and
extend the search both to lower luminosities and, by virtue of the
NICMOS/IRAC combination, to higher redshift. The goal is to count and
characterize representative sources at z~6-10 and to delineate the
redshift range of activity for the planning of future observations.

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)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 08 08
FGS REacq 06 06
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS: (None)