Daily 3741

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3741

PERIOD COVERED: DOYs 324-326

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 9993

Cycle 12 NICMOS dark current, shading profile, and read noise
monitoring program

The purpose of this proposal is to monitor the dark current, read
noise, and shading profile for all three NICMOS detectors throughout
the duration of Cycle 12. This proposal is an essentially unchanged
continuation of PID 9636 which cover the duration of Cycle 11.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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.

ACS/HRC 10441

Characterizing a Newly-Found Extrasolar Planet

We propose to observe transits of the newly-discovered extrasolar
planet TRES-1 using {1} ACS/HRC to obtain precise time-series
photometry of the transit, and {2} NICMOS to measure the strength of
water vapor absorption in the planetary atmosphere. The visible light
curve will permit an accurate estimate of the planet's diameter by
resolving uncertainty concerning the diameter of the parent star, and
the water vapor observation can be used to test models of the
structure, clouds and composition in the planet's upper atmosphere.

FGS 10432

Precise Distances to Nearby Planetary Nebulae

We propose to carry out astrometry with the FGS to obtain accurate and
precise distances to four nearby planetary nebulae. In 1992, Cahn et
al. noted that ``The distances to Galactic planetary nebulae remain a
serious, if not THE most serious, problem in the field, despite
decades of study.'' Twelve years later, the same statement still
applies. Because the distances to planetary nebulae are so uncertain,
our understanding of their masses, luminosities, scale height, birth
rate, and evolutionary state is severely limited. To help remedy this
problem, HST astrometry can guarantee parallaxes with half the error
of any other available approach. These data, when combined with
parallax measurements from the USNO, will improve distance
measurements by more than a factor of two, producing more accurate
distances with uncertainties that are of the order of ~6%. Lastly,
most planetary nebula distance scales in the literature are
statistical. They require several anchor points of known distance in
order to calibrate their zero point. Our program will provide "gold
standard" anchor points by the end of 2006, a decade before any
anticipated results from future space astrometry missions.

ACS/HRC/WFC 10367

ACS CCDs daily monitor- cycle 13 - part 1

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.

ACS/HRC 10272

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for
supernovae {SNe}, most notably our Lick Observatory Supernova Search
{LOSS}, have found hundreds of SNe, many of them in quite nearby
galaxies {cz 4000 km/s}. Most of the objects were discovered before
maximum brightness, and have follow-up photometry and spectroscopy;
they include some of the best-studied SNe to date. We propose to
conduct a snapshot imaging survey of the sites of some of these nearby
objects, to obtain late-time photometry that {through the shape of the
light and color curves} will help reveal the origin of their lingering
energy. The images will also provide high- resolution information on
the local environment of SNe that are far superior to what we can
procure from the ground. For example, we will obtain color-color and
color-magnitude diagrams of stars in these SN sites, to determine
their progenitor masses and constraints on the reddening. Recovery of
the SNe in the new HST images will also allow us to actually pinpoint
their progenitor stars in cases where pre-explosion images exist in
the HST archive. Use of ACS rather than WFPC2 will make our snapshot
survey even more valuable than our Cycle 9 survey. This Proposal is
complementary to our Cycle 13 archival proposal, in which we outline a
plan for using existing HST images to glean information about SN
environments.

ACS/WFC 10237

Low-Ionization BALs: Evolution or Orientation?

We propose to test the hypothesis that Low-Ionization Broad Absorption
Line Quasars {LoBALs} represent a special stage of quasar evolution:
young quasars in systems with strong interaction and star-formation.
We will carry out high resolution imaging using ACS/WFC and NICMOS to
measure the properties of the host galaxies of four LoBAL quasars at z
= 0.9 - 2.0 that show strong overlapping FeII absorption troughs. The
ACS imaging will be carried out in the passband with the strongest BAL
absorption, acting as a natural coronagraph. This results in a
reduction of quasar light by a factor of 15 - 26 in these passbands,
providing arguably the best view of the host galaxies of luminous,
high-redshift quasars. This method allows efficient detection and
detailed modeling of the host galaxy morphology in the rest-frame
ultraviolet, which is most sensitive to star formation and galaxy
interaction. We will also use NICMOS imaging to measure the rest-
frame light from the host galaxy to probe the old stellar populations
where the host galaxy is likely to be brighter. It has been suggested
that LoBALs might not be explained simply as an orientation effect but
rather as an early phase of quasar evolution. Such a phase is
typically associated with large amounts of dust and gas, and young
galaxies with strong star formation. With HST observations, we will
study the color and morphology of the FeLoBAL quasar host galaxies,
and measure the age of their dominant stellar populations. We will
also measure the density of close companions, and, in particular, look
for signs of ongoing or recent mergers. These measurements will be
compared to those of control samples of normal quasars at similar
redshift. If LoBALs are indeed young systems, then their host galaxies
are expected to show stronger interactions and merger activity,
younger stellar ages, and regions with strong star formation. If the
LoBAL host galaxies show no significant difference from those of
normal quasars, it will support the view that LoBAL quasars are not a
distinct population and that all quasars have BAL outflows along some
lines of sight.

NIC/NIC3 10226

The NICMOS Grism Parallel Survey

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7z1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial--but poorly observed--redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

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/HRC/NIC1/WFC 10190

The Star Formation History and Metallicity Evolution of M33: A
Comprehensive Study of Disk Evolution

We will obtain deep, panchromatic imaging photometry of stellar
populations in four fields ranging from 0.5 to 4 scale lengths across
the disk of the Local Group spiral M33. The observations are designed
to detect the oldest main-sequence turnoffs in three outer disk
fields, and to reach the crowding limit in the innermost field. We
will combine the photometry data with information we already have
in-hand on abundances from stars and H II regions in M33 to derive the
star formation history and metallicity evolution of the M33 disk. The
information from our four fields will allow us to obtain {1} the ages
of the oldest disk stars and the radial variation of their ages; {2}
the radial variation of the star formation history and its nature
{e.g., constant, declining, or bursting}; and {3} the metallicity
distribution in each field and the time evolution of the metallicity
gradient. Our team, an experienced mix of photometrists,
spectroscopists, and galaxy evolution theorists, will use the results
from this program to construct a comprehensive chemo- dynamical model
for the M33 disk. This detailed study of M33 will be a key in
developing an understanding of the formation and evolution of disks
that can be applied to studies of disks at both low and high redshift,
and will also yield a wealth of information on stellar populations,
chemical evolution, and star clusters that will be of great value to
future investigators.

ACS/WFC 10181

ACS/NICMOS Imaging of Bright Lyman Break Galaxy Candidates from SDSS

The recent surprising discovery of six unusually bright {r~20 mag}
Lyman break galaxy {LBG} candidates with z=2.45-2.80 in the Sloan
Digital Sky Survey {SDSS} raises a number of questions that only HST
can address. Specifically, what is the true nature of these objects,
and what role if any is played by gravitational lensing? We propose to
use the superior resolution and sensitivity of ACS and NICMOS to
obtain deep images of these objects and their environments. Compared
to SDSS images, HST will allow us to determine their morphologies
{extended, point-source, or lensed}, the appearance of their
environments {rich or poor}, and to detect any faint foreground groups
or clusters that might be responsible for lensing these objects. All
outcomes would be intriguing. If the objects are lensed, it increases
from 1 {MS1512-cB58} to 7 the number of normal LBGs bright enough to
study individually. If they are instead unlensed point sources, they
will represent a new class of previously unidentified absorption-line
quasars. Finally, if they are unlensed and extended star-forming
galaxies, they are at least 4mag brighter than L_* LBGs, thus making
them the most luminous star-forming objects yet seen, representing a
heretofore unknown extreme population of objects.

ACS/HRC 10180

Ultracompact Blue Dwarfs: Galaxy Formation in the Local Universe?

Recent observations suggest that very low-mass galaxies in the local
universe are still in the process of formation. To investigate this
issue we propose to obtain deep ACS HRC images in the U, V and I bands
of a sample of 11 "ultracompact" blue dwarf galaxies {UCBDs}
identified in the Sloan Digital Sky Survey. These objects are nearby
{z 0.009}, actively star-forming, and have extremely small angular
and physical sizes {d 6" and D 1 kpc}. They also tend to reside in
voids. Our WFPC2 images of the prototype object of this class, POX
186, reveal this tiny object to have a highly disturbed morphlogy
indicative of a recent {within 10^8 yr} collision between two small {~
100 pc} clumps of stars that could represent the long-sought building
blocks predicted by the Press-Schechter model of hierarchical galaxy
formation. This collision has also triggered the formation of a
"super" star cluster {SSC} at the object's core that may be the
progenitor of a globular cluster. POX 186 thus appears to be a very
small dwarf galaxy in the process of formation. This exciting
discovery strongly motivates HST imaging of a full sample of UCBDs in
order to determine if they have morphologies similar to POX 186. HST
images are essential for resolving the structure of these objects,
including establishing the presence of SSCs. HST also offers the only
way to determine their morphologies in the near UV. The spectra of the
objects available from the SDSS will also allow us to measure their
star formation rates, dust content and metallicities. In addition to
potentially providing the first direct evidence of Press- Schechter
building blocks, these data could yield insight into the relationship
between galaxy and globular cluster formation, and will serve as a
test of the recent "downsizing" model of galaxy formation in which the
least massive objects are the last to form.

ACS/WFC 10178

Imaging Polarimetry of Young Stellar Objects with ACS and NICMOS: A
study in dust grain evolution

The formation of planetary systems is intimately linked to the dust
population in circumstellar disks, thus understanding dust grain
evolution is essential to advancing our understanding of how planets
form. By combining {1} the high resolution polarimetric capabilities
of ACS and NICMOS, {2} powerful 3-D radiative transfer codes, and {3}
observations of objects known to span the earliest stellar
evolutionary phases, we will gain crucial insight into the initial
phases of dust grain growth: evolution away from an ISM distribution.
Fractional polarization is a strong function of wavelength, therefore
by comparing polarimetric images in the optical and infrared, we can
sensitively constrain not only the geometry and optical depth of the
scattering medium, but also the grain size distribution. By observing
objects representative of the earliest evolutionary sequence of YSOs,
we will be able to investigate how the dust population evolves in size
and distribution during the crucial transition from a disk+envelope
system to a disk+star system. The proposed study will help to
establish the fundamental time scales for the initial depletion of
ISM-like grains: the first step in understanding the transformation
from small submicron sized dust grains, to large millimeter sized
grains, and untimely to planetary bodies.

NIC2 10177

Solar Systems In Formation: A NICMOS Coronagraphic Survey of
Protoplanetary and Debris Disks

Until recently, despite decades of concerted effort applied to
understanding the formation processes that gave birth to our solar
system, the detailed morphology of circumstellar material that must
eventually form planets has been virtually impossible to discern. The
advent of high contrast, coronagraphic imaging as implemented with the
instruments aboard HST has dramatically enhanced our understanding of
natal planetary system formation. Even so, only a handful of evolved
disks {~ 1 Myr and older} have been imaged and spatially resolved in
light scattered from their constituent grains. To elucidate the
physical processes and properties in potentially planet-forming
circumstellar disks, and to understand the nature and evolution of
their grains, a larger spatially resolved and photometrically reliable
sample of such systems must be observed. Thus, we propose a highly
sensitive circumstellar disk imaging survey of a well-defined and
carefully selected sample of YSOs {1-10 Myr T Tau and HAeBe stars} and
{ app 10 Myr} main sequence stars, to probe the posited epoch of
planetary system formation, and to provide this critically needed
imagery. Our resolved images will shed light on the spatial
distributions of the dust in these thermally emissive disks. In
combination with their long wavelength SEDs the physical properties of
the grains will be discerned, or constrained by our photometrically
accurate surface brightness sensitivity limits for faint disks which
elude detection. Our sample builds on the success of the exploratory
GTO 7233 program, using two-roll per orbit PSF-subtracted NICMOS
coronagraphy to provide the highest detection sensitivity to the
smallest disks around bright stars which can be imaged with HST. Our
sample will discriminate between proposed evolutionary scenarios while
providing a legacy of cataloged morphologies for interpreting mid- and
far-IR SEDs that the recently launched Spitzer Space Telescope will
deliver.

NIC2 10169

Star Formation in Luminous Infrared Galaxies: giant HII Regions and
Super Star Clusters

Luminous Infrared Galaxies {LIRGs, LIR = 10^11-10^12Lsol} and
Ultraluminous Infrared Galaxies {LIR10^12Lsol} account for
approximately 75% of all the galaxies detected in the mid-infrared in
the redshift range z=0-1.5. In the local universe it is found that
LIRGs are predominantly powered by intense star formation {SF}.
However, the physical conditions and processes governing such dramatic
activity over scales of tens to a few hundred parsecs are poorly
known. In the last decade HST has been playing a significant role,
mainly with the discovery of super star clusters {SSCs}, and more
recently, giant HII regions. Based on observations of a few LIRGs, we
found that these giant HII regions and associated SSCs appear to be
more common in LIRGs than in normal galaxies, and may dominate the
star formation activity in LIRGs. A larger sample is required to
address fundamental questions. We propose an HST/NICMOS targeted
campaign of a volume limited sample {v5200km/s} of 24 LIRGs. This
proposal will probe the role of giant HII regions in the overall
energetics of the current star formation, their relation to SSCs, and
the dependence of star formation properties on other parameters of
LIRGs. Such detailed knowledge of the SF properties of LIRGs in the
local universe is essential for understanding galaxies at high
redshift.

NIC2 10160

The nuclear scattering geometry of Seyfert galaxies

Orientation-based unification schemes are now well-established as the
basis for understanding the relationships between different classes of
AGN. However, our recent study of the optical polarization properties
of Seyfert 1 galaxies indicates that scattered light emerging from
these objects often follows a different path to that in Seyfert 2's,
indicating that the simplest unification geometry is incomplete. We
have developed a generic scattering model for Seyfert nuclei which
includes a compact, equatorial scattering region located within the
circum-nuclear torus and the 'classic' polar scattering region outside
it. We propose to test this model by using NICMOS to make NIR imaging
observations that will allow us to isolate the two scattering regions
within individual objects.

ACS/WFC 10118

Imaging the Chemical Distribution in Type Ia SN Ejecta

We know Type Ia supernovae are thermonuclear explosions of CO white
dwarfs, but we don't know the specifics of how the nuclear burning
process proceeds from the core outward once it starts. The
thermonuclear instability is thought to start off as a subsonic,
turbulent deflagration or burning wave but then, at some point, may
transition into a blast or detonation wave. In such "delayed
detonation" models, differences between normal and subluminous Type Ia
SNe reflect differences in the amount of burning that has occurred in
the pre-detonation phase. More burning helps to pre-expand the WD
before passage of the detontation wave, which then results in
different final element abundances and internal Fe-rich ejecta
structure. Directly imaging the 2-D chemical distribution of ejecta
from a Type Ia SN is actually possible in the case of the subluminous
Type Ia SN 1885, which occurred on the near-side of M31's central
bulge. This 119 year old remnant is visible -- from its core to its
outer edge -- via strong optical/UV Ca and Fe line absorptions.
Remarkably, the SNR appears to still be in a nearly free expansion
phase, meaning that the elemental stratification seen present today
accurately reflects SN Ia explosive nucleosynthesis physics. We
propose to obtain ACS WFC/HRC images of SN 1885 in order to take
advantage of this extraordinary situation: Having a young, nearby Type
Ia SN remnant visible in silhouette against a galaxy-size light table.
These unique observations will reveal a SN Ia's Ca and Fe ejecta
distribution, density structure, sphericity, and ionization state as a
function of expansion velocity, thereby confronting various SN Ia
models with detailed ejecta stratification and expansion velocity
maps.

ACS/WFC 10099

The Parallax of Geminga

The distances to neutron stars are a fundamental parameter that
impacts estimates of radii and luminosities, both of which have
important ramifications for neutron star heating and cooling and for
the equation of state of nuclear matter. A radius measured to 5%
accuracy will provide useful astrophysical constraints on the equation
of matter at nuclear densities. This requires an accurate measurement
of the distance. Caraveo et al. have reported a distance to the
isolated pulsar Geminga based on three WFPC2 images. We have not been
able to reproduce that result. We request time with the ACS/WFC over
two years to obtain 4 images in order to determine the parallax of
Geminga. In addition to the general importance of understanding
neutron star radii and luminosities, this will provide specific
insights into the history of gamma ray pulsars in general, and of
Geminga itself. We have obtained the first two images {cycle 12};
these two cycle 13 images will complete the program.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.) None

COMPLETED OPS REQs: None

OPS NOTES EXECUTED:
0900-1 COMMAND PROBLEM @ 326/17:33:18z
0900-1 COMMAND PROBLEM @ 327/04:17:22z
0916-0 Tabulation of Slew Attitude Error (Miss-distance) @ 327/0142z

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 22 22
FGS Reacq 24 24
FHST Update 35 35
LOSS of LOCK


SIGNIFICANT EVENTS: None