Daily Report #5042

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5042

PERIOD COVERED: 5am February 26 - 5am March 1, 2010 (DOY 057/10:00z-060/10:00z)

OBSERVATIONS SCHEDULED

WFC3/UV 12049

Improve the Measurement of Vesta's Pole Orientation to Support Dawn
Mission

NASA?s Dawn spacecraft is scheduled to go into orbit around the main
belt asteroid 4 Vesta in July 2011. Currently the project is using a
3-? pole position uncertainty of Vesta of 12? for spacecraft
trajectory design. We have determined that with an additional set of
Hubble observations at Vesta?s next opposition in February 2010, that
the pole position uncertainty can be reduced by a factor of 4. This
will reduce both cost and risk to the Dawn mission, and is likely to
increase the stay time at Vesta and will add to the scientific return
of the mission. The requested observing window in February 2010 is the
last and single best opportunity that can benefit the Dawn mission,
but it is before the start of the next HST Cycle.

WFC3/UVIS 12018

Ultra-Luminous X-Ray Sources in the Most Metal-Poor Galaxies

There is growing observational and theoretical evidence to suggest
that Ultra-Luminous X-ray sources (ULX) form preferentially in low
metallicity environments. Here we propose a survey of 27 nearby (
30Mpc) star-forming Extremely Metal Poor Galaxies (Z5% solar). There
are almost no X-ray observations of such low abundance galaxies (3 in
the Chandra archive). These are the most metal-deficient galaxies
known, and a logical place to find ULX if they favor metal-poor
systems. We plan to test recent population synthesis models which
predict that ULX should be very numerous in metal-poor galaxies. We
will also test the hypothesis that ULX form in massive young star
clusters, and ask for HST time to obtain the necessary imaging data.

COS/FUV 12011

Magnetic Heating of the Outer Atmospheres of Very Low Mass Dwarfs

The detections of FUV and X-ray emissions from very low mass stars and
brown dwarfs have confirmed that stellar magnetic activity can survive
even at these low stellar masses. The emissions are qualitatively
similar to those from active stars, despite the dramatic differences
between the characteristics of an ultracool (M7) stellar atmosphere
and those of earlier type cool stars. It is currently an open question
how the structures and magnetic heating which exists in these very low
mass stars compare with those seen in higher mass active stars. We
propose to take Chandra and HST/COS spectra of two nearby active very
low mass stars in order to determine the effect that these large-scale
fields have on transition region and coronal structures.

ACS/WFC 11995

CCD Daily Monitor (Part 2)

This program comprises basic tests for measuring the read noise and
dark current of the ACS WFC and for tracking the growth of hot pixels.
The recorded frames are used to create bias and dark reference images
for science data reduction and calibration. This program will be
executed four days per week (Mon, Wed, Fri, Sun) for the duration of
Cycle 17. To facilitate scheduling, this program is split into three
proposals. This proposal covers 320 orbits (20 weeks) from 1 February
2010 to 20 June 2010.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more
reliably removed from science data using darks taken with the same
exposure sequences as the science data, than with a single dark
current image scaled by desired exposure time. Therefore, dark current
images must be collected using all sample sequences that will be used
in science observations. These observations will be used to monitor
changes in the dark current of the WFC3-IR channel on a day-to-day
basis, and to build calibration dark current ramps for each of the
sample sequences to be used by Gos in Cycle 17. For each sample
sequence/array size combination, a median ramp will be created and
delivered to the calibration database system (CDBS).

WFC3/UVIS 11908

Cycle 17: UVIS Bowtie Monitor

Ground testing revealed an intermittent hysteresis type effect in the
UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially found via an unexpected bowtie-shaped feature in flatfield
ratios, subsequent lab tests on similar e2v devices have since shown
that it is also present as simply an overall offset across the entire
CCD, i.e., a QE offset without any discernable pattern. These lab
tests have further revealed that overexposing the detector to count
levels several times full well fills the traps and effectively
neutralizes the bowtie. Each visit in this proposal acquires a set of
three 3x3 binned internal flatfields: the first unsaturated image will
be used to detect any bowtie, the second, highly exposed image will
neutralize the bowtie if it is present, and the final image will allow
for verification that the bowtie is gone.

WFC3/UVIS 11907

UVIS Cycle 17 Contamination Monitor

The UV throughput of WFC3 during Cycle 17 is monitored via weekly
standard star observations in a subset of key filters covering
200-600nm and F606W, F814W as controls on the red end. The data will
provide a measure of throughput levels as a function of time and
wavelength, allowing for detection of the presence of possible
contaminants.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set
of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K
subarray biases are acquired at less frequent intervals throughout the
cycle to support subarray science observations. The internals from
this proposal, along with those from the anneal procedure (Proposal
11909), will be used to generate the necessary superbias and superdark
reference files for the calibration pipeline (CDBS).

FGS 11875

Monitoring FGS2R2 Distortion and Alignment After SMOV4

This proposal monitors changes in the FGS2R2 distortion and alignment
after SMOV4 by observing selected stars in M35 in Position mode. Data
from each epoch are compared to track changes in FGS2R2. When the rate
of change becomes sufficiently slow, FGS2R2 will be cleared for a
mini-OFAD and FGS-FGS alignment calibration (carried out in another
phase 2 proposal).

FGS 11871

Long Term Stability of FGS1R in Position Mode

This proposal resumes the Long Term Monitoring of FGS1R in Position
Mode using stars in M35 that are a subset of the FGS "OFAD catalog"
using both the "fall" and "spring" seasons (the spring orient was not
available under two gyro mode). The data acquired by this proposal are
used to update the FGS1R "rhoA & kA" parameters that are associated
with the OFAD solution that is applicable at the observation's epoch.
These values are critical to support sub-milli arcsecond astrometry
with FGS1R.

This particular proposal also include a FGS3 visit to M35 for post SM4
verification of its calibration status.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to monitor the bias in the 1x1, 1x2,
2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up
high-S/N superbiases and track the evolution of hot columns.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

WFC3/UVIS/IR 11835

The Multi-Faceted X-Ray Activity of Low-Redshift Active Galaxies

We propose ACIS-I observations of Chandra-unobserved low-redshift 3CRR
active galaxies and their environments. The data will complete Chandra
observations of 3CRR at z 0.1, making the sample useful for
statistical studies. Only Chandra can resolve the multiple components
of these sources, as is needed for an improved understanding of source
physics and gas heating. The imaging and spectroscopy of cores, jets,
hot spots, and atmospheres will be of permanent legacy value. We will
use the data to investigate particle acceleration, interactions
between radio plasma and the ISM and IGM, the emission mechanisms of
hot spots, and AGN fueling. Comparison with our complete Spitzer
coverage and HST images will aid interpretation. The dataset will be
made public immediately.

ACS/WFC3 11735

The LSD Project: Dynamics, Merging and Stellar Populations of a Sample
of Well-Studied LBGs at z~3

A large observational effort with the ground-based ESO/VLT telescopes
allowed us to obtain deep, spatially-resolved, near-IR spectra of
complete sample of 11 Lyman-Break Galaxies at z~3.1. These
observations were used to obtain, for the first time, the metallicity
and the dynamical properties of a sample of objects that, albeit
small, is representative of the total population of the LBGs. We
propose to use HST to obtain high-resolution optical and near-IR
images of this sample of LBGs in order to study the broad-band
morphology and the stellar light distribution of these galaxies. These
images, exploiting the superior spatial resolution of HST images and
the low-background : 1- will allow a precise measure of the dynamical
mass from the velocity field derived with spectroscopy; 2- will permit
a comparison of the distribution of star formation (from the line
emission) with the underlying stellar population, and, 3- will be used
to check if the complex velocity field and the multiple line-emitting
regions detected in most targets can be ascribed to on-going mergers.
This accurate study will shed light on a number of unsolved problems
still affecting the knowledge of the LBGs.

WFC3/UVIS 11732

The Temperature Profiles of Quasar Accretion Disks

We can now routinely measure the size of quasar accretion disks using
gravitational microlensing of lensed quasars. At optical wavelengths
we observe a size and scaling with black hole mass roughly consistent
with thin disk theory but the sizes are larger than expected from the
observed optical fluxes. One solution would be to use a flatter
temperature profile, which we can study by measuring the wavelength
dependence of the disk size over the largest possible wavelength
baseline. Thus, to understand the size discrepancy and to probe closer
to the inner edge of the disk we need to extend our measurements to UV
wavelengths, and this can only be done with HST. For example, in the
UV we should see significant changes in the optical/UV size ratio with
black hole mass. We propose monitoring 5 lenses spanning a broad range
of black hole masses with well-sampled ground based light curves,
optical disk size measurements and known GALEX UV fluxes during Cycles
17 and 18 to expand from our current sample of two lenses. We would
obtain 5 observations of each target in each Cycle, similar to our
successful strategy for the first two targets.

COS/NUV/FUV 11727

UV Spectroscopy of Local Lyman Break Galaxy Analogs: New Clues to
Galaxy Formation in the Early Universe

Much of our information about galaxy evolution and the interaction
between galaxies and the IGM at high-z has been provided by the Lyman
Break Galaxies (LBGs). However, it is difficult to investigate these
faint and distant objects in detail. To address this, we have used the
GALEX All-Sky Imaging Survey and the SDSS to identify for the first
time a rare population of low- redshift galaxies with properties
remarkably similar to the high-redshift LBGs. These local "Lyman Break
Analogs" (LBAs) resemble LBGs in terms of morphology, size, UV
luminosity, star formation rate, UV surface brightness, stellar mass,
velocity dispersion, metallicity, and dust content. We are assembling
a wide range of data on these objects with the goal of using them as
local laboratories for better understanding the relevant astrophysical
processes in LBGs. These data include HST imaging (95 orbits in Cy15
and 16), Spitzer photometry and spectroscopy, Chandra and XMM X-ray
imaging and spectroscopy, and near-IR integral field spectroscopy
(VLT, Keck, and Gemini). In this proposal we are requesting the most
important missing puzzle piece: far-UV spectra with a signal-to-noise
and spectral resolution significantly better than available for
typical LBGs. We will use these spectra to study the LBA's galactic
winds, probe the processes that regulate the escape of Ly-a and Lyman
continuum radiation, determine chemical abundances for the stars and
gas, and constrain the form of the high-end of the Initial Mass
Function. Adding these new COS data will give us vital information
about these extraordinary sites of star formation in the local
universe. In so-doing it will also shed new light on the processes
that led to the formation of stars, the building of galaxies, and the
enrichment and heating of the IGM in the early universe.

WFC3/IR 11719

A Calibration Database for Stellar Models of Asymptotic Giant Branch
Stars

Studies of galaxy formation and evolution rely increasingly on the
interpretation and modeling of near-infrared observations. At these
wavelengths, the brightest stars are intermediate mass asymptotic
giant branch (AGB) stars. These stars can contribute nearly 50% of the
integrated luminosity at near infrared and even optical wavelengths,
particularly for the younger stellar populations characteristic of
high-redshift galaxies (z1). AGB stars are also significant sources
of dust and heavy elements. Accurate modeling of AGB stars is
therefore of the utmost importance.

The primary limitation facing current models is the lack of useful
calibration data. Current models are tuned to match the properties of
the AGB population in the Magellanic Clouds, and thus have only been
calibrated in a very narrow range of sub-solar metallicities.
Preliminary observations already suggest that the models are
overestimating AGB lifetimes by factors of 2-3 at lower metallicities.
At higher (solar) metallicities, there are no appropriate observations
for calibrating the models.

We propose a WFC3/IR SNAP survey of nearby galaxies to create a large
database of AGB populations spanning the full range of metallicities
and star formation histories. Because of their intrinsically red
colors and dusty circumstellar envelopes, tracking the numbers and
bolometric fluxes of AGB stars requires the NIR observations we
propose here. The resulting observations of nearby galaxies with deep
ACS imaging offer the opportunity to obtain large (100-1000's)
complete samples of AGB stars at a single distance, in systems with
well-constrained star formation histories and metallicities.

WFC3/UVIS 11714

Snapshot Survey for Planetary Nebulae in Local Group Globular Clusters

Planetary nebulae (PNe) in globular clusters (GCs) raise a number of
interesting issues related to stellar and galactic evolution. The
number of PNe known in Milky Way GCs, four, is surprisingly low if one
assumes that all stars pass through a PN stage. However, it is likely
that the remnants of stars now evolving in galactic GCs leave the AGB
so slowly that any ejected nebula dissipates long before the star
becomes hot enough to ionize it. Thus there should not be ANY PNe in
Milky Way GCs--but there are four! It has been suggested that these
Pne are the result of mergers of binary stars within GCs, i.e., that
they are descendants of blue stragglers. The frequency of occurrence
of PNe in external galaxies poses more questions, because it shows a
range of almost an order of magnitude.

I propose a SNAPshot survey aimed at discovering PNe in the GC systems
of Local Group galaxies outside the Milky Way. These clusters, some of
which may be much younger than their counterparts in our galaxy, might
contain many more PNe than those of our own galaxy. I will use the
standard technique of emission-line and continuum imaging, which
easily discloses PNe. This proposal continues a WFPC2 program started
in Cycle 16, but with the more powerful WFC3. As a by-product, the
survey will also produce color-magnitude diagrams for numerous
clusters for the first time, reaching down to the horizontal branch.

ACS/WFC/WFC3/UV 11711

A Definitive Distance to the Coma Core Ellipticals

As the richest galaxy cluster in the local universe (cz 10, 000
km/s), the Coma cluster continues to serve as the standard of
comparison for numerous studies of galaxy properties and scaling
relations in clusters. The central importance of Coma has been
recognized with two recent HST large programs: a Treasury survey to
study the dwarf galaxy population by imaging 82 different ACS/WFC
pointings, and a program to measure Cepheid distances to two spiral
galaxies projected within the Coma core region. An accurate distance
to the Coma core is essential for comparing the galaxy luminosities
and sizes to nearby galaxies in Virgo and Fornax, while an accurate
peculiar velocity is needed for correctly tying to more distant
clusters. However, experience dictates that Cepheid distances to
clusters must be carefully verified against accurate measurements to
the dominant early-type population, especially for such an
unprecedented effort as the Coma Cepheid search (the completion of
which remains uncertain). We propose to measure highly accurate (3-4%
internal error per galaxy) SBF distances to the two giant Coma core
ellipticals. The reliability of the SBF method with the ACS/WFC has
been repeatedly demonstrated, and it is so efficient that it requires
only 3% of the number of orbits dedicated to the two current large
Coma programs. The precise ACS SBF Coma core distance will also
provide a good constraint on the Coma peculiar velocity, thus
improving the accuracy of comparisons to distant clusters. Finally,
our program will answer some longstanding puzzles surrounding the rich
globular cluster population in the core of this archetypal galaxy
cluster.

WFC3/UVIS/IR 11702

Search for Very High-z Galaxies with WFC3 Pure Parallel

WFC3 will provide an unprecedented probe to the early universe beyond
the current redshift frontier. Here we propose a pure parallel program
using this new instrument to search for Lyman-break galaxies at
6.5z8.8 and to probe the epoch of reionization, a hallmark event in
the history of the early universe. We request 200 orbits, spreading
over 30 ~ 50 high Galactic latitude visits (|b|20deg) that last for 4
orbits and longer, resulting a total survey area of about 140~230
square arcminute. Based on our understanding of the new HST parallel
observation scheduling process, we believe that the total number of
long-duration pure parallel visits in Cycle 17 should be sufficient to
accommodate our program. We waive all proprietary rights to our data,
and will also make the enhanced data products public in a timely
manner.

(1) We will use both the UVIS and the IR channels, and do not need to
seek optical data from elsewhere.

(2) Our program will likely triple the size of the probable candidate
samples at z~7 and z~8, and will complement other targeted programs
aiming at the similar redshift range.

(3) Being a pure parallel program, our survey will only make very
limited demand on the scarce HST resources. More importantly, as the
pure parallel pointings will be at random sight-lines, our program
will be least affected by the bias due to the large scale structure
("cosmic variance").

(4) We aim at the most luminous LBG population, and will address the
bright-end of the luminosity function at z~8 and z~7. We will
constrain the value of L* in particular, which is critical for
understanding the star formation process and the stellar mass assembly
history in the first few hundred million years of the universe.

(5) The candidates from our survey, most of which will be the
brightest ones that any surveys would be able to find, will have the
best chance to be spectroscopically confirmed at the current 8--10m
telescopes.

(6) We will also find a large number of extremely red, old galaxies at
intermediate redshifts, and the fine spatial resolution offered by the
WFC3 will enable us constrain their formation history based on the
study of their morphology, and hence shed light on their connection to
the very early galaxies in the universe.

COS/FUV 11687

SNAPing Coronal Iron

This is a Snapshot Survey to explore two forbidden lines of highly
ionized iron in late-type coronal sources. Fe XII 1349 (T~ 2 MK) and
Fe XXI 1354 (T~ 10 MK) -- well known to Solar Physics -- have been
detected in about a dozen cool stars, mainly with HST/STIS. The UV
coronal forbidden lines are important because they can be observed
with velocity resolution of better than 15 km/s, whereas even the
state-of-the-art X-ray spectrometers on Chandra can manage only 300
km/s in the kilovolt band where lines of highly ionized iron more
commonly are found. The kinematic properties of hot coronal plasmas,
which are of great interest to theorists and modelers, thus only are
accessible in the UV at present. The bad news is that the UV coronal
forbidden lines are faint, and were captured only in very deep
observations with STIS. The good news is that 3rd-generation Cosmic
Origins Spectrograph, slated for installation in HST by SM4, in a mere
25 minute exposure with its G130M mode can duplicate the sensitivity
of a landmark 25-orbit STIS E140M observation of AD Leo, easily the
deepest such exposure of a late-type star so far. Our goal is to build
up understanding of the properties of Fe XII and Fe XXI in additional
objects beyond the current limited sample: how the lineshapes depend
on activity, whether large scale velocity shifts can be detected, and
whether the dynamical content of the lines can be inverted to map the
spatial morphology of the stellar corona (as in "Doppler Imaging'').
In other words, we want to bring to bear in the coronal venue all the
powerful tricks of spectroscopic remote sensing, well in advance of
the time that this will be possible exploiting the corona's native
X-ray radiation. The 1290-1430 band captured by side A of G130M also
contains a wide range of key plasma diagnostics that form at
temperatures from below 10, 000 K (neutral lines of CNO), to above
200, 000 K (semi-permitted O V 1371), including the important bright
multiplets of C II at 1335 and Si IV at 1400; yielding a diagnostic
gold mine for the subcoronal atmosphere. Because of the broad value of
the SNAP spectra, beyond the coronal iron project, we waive the normal
proprietary rights.

WFC3/UVIS 11650

Mutual Orbits, Colors, Masses, and Bulk Densities of 3 Cold Classical
Trans-Neptunian Binaries

Many Trans-Neptunian Objects (TNOs) have been found to be binary or
multiple systems. As in other astrophysical settings, Trans-Neptunian
Binaries (TNBs) offer uniquely valuable information. Their mutual
orbits allow the direct determination of their system masses, perhaps
the most fundamental physical quantity of any astronomical object.
Their frequency of occurrence and dynamical characteristics provide
clues to formation conditions and evolution scenarios affecting both
the binaries and their single neighbors. Combining masses with sizes,
bulk densities can be measured. Densities constrain bulk composition
and internal structure, key clues to TNO origins and evolution over
time. Several TNB bulk densities have been determined, hinting at
interesting trends. But none of them belongs to the Cold Classical
sub-population, the one group of TNOs with demonstrably distinct
physical characteristics. Two top-priority Spitzer programs will soon
observe and measure the sizes of 3 Cold Classical TNBs. This proposal
seeks to determine the mutual orbits and thus masses of these systems,
enabling computation of their densities.

WFC3/UVIS/IR 11644

A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into
the Formation of the Outer Solar System

The eight planets overwhelmingly dominate the solar system by mass,
but their small numbers, coupled with their stochastic pasts, make it
impossible to construct a unique formation history from the dynamical
or compositional characteristics of them alone. In contrast, the huge
numbers of small bodies scattered throughout and even beyond the
planets, while insignificant by mass, provide an almost unlimited
number of probes of the statistical conditions, history, and
interactions in the solar system. To date, attempts to understand the
formation and evolution of the Kuiper Belt have largely been dynamical
simulations where a hypothesized starting condition is evolved under
the gravitational influence of the early giant planets and an attempt
is made to reproduce the current observed populations. With little
compositional information known for the real Kuiper Belt, the test
particles in the simulation are free to have any formation location
and history as long as they end at the correct point. Allowing
compositional information to guide and constrain the formation,
thermal, and collisional histories of these objects would add an
entire new dimension to our understanding of the evolution of the
outer solar system. While ground based compositional studies have hit
their flux limits already with only a few objects sampled, we propose
to exploit the new capabilities of WFC3 to perform the first ever
large-scale dynamical-compositional study of Kuiper Belt Objects
(KBOs) and their progeny to study the chemical, dynamical, and
collisional history of the region of the giant planets. The
sensitivity of the WFC3 observations will allow us to go up to two
magnitudes deeper than our ground based studies, allowing us the
capability of optimally selecting a target list for a large survey
rather than simply taking the few objects that can be measured, as we
have had to do to date. We have carefully constructed a sample of 120
objects which provides both overall breadth, for a general
understanding of these objects, plus a large enough number of objects
in the individual dynamical subclass to allow detailed comparison
between and within these groups. These objects will likely define the
core Kuiper Belt compositional sample for years to come. While we have
many specific results anticipated to come from this survey, as with
any project where the field is rich, our current knowledge level is
low, and a new instrument suddenly appears which can exploit vastly
larger segments of the population, the potential for discovery -- both
anticipated and not -- is extraordinary.

WFC3/ACS/IR 11597

Spectroscopy of IR-Selected Galaxy Clusters at 1 z 1.5

We propose to obtain WFC3 G141 and G102 slitless spectroscopy of
galaxy clusters at 1 z 1.5 that were selected from the IRAC survey
of the Bootes NDWFS field. Our IRAC survey contains the largest sample
of spectroscopically confirmed clusters at z 1. The WFC3 grism data
will measure H-alpha to determine SFR, and fit models to the low
resolution continua to determine stellar population histories for the
brighter cluster members, and redshifts for the red galaxies too faint
for ground-based optical spectroscopy.

WFC3/UVIS 11595

Turning Out the Light: A WFC3 Program to Image z2 Damped Lyman Alpha
Systems

We propose to directly image the star-forming regions of z2 damped
Lya systems (DLAs) using the WFC3/UVIS camera on the Hubble Space
Telescope. In contrast to all previous attempts to detect the galaxies
giving rise to high redshift DLAs, we will use a novel technique that
completely removes the glare of the background quasar. Specifically,
we will target quasar sightlines with multiple DLAs and use the higher
redshift DLA as a ``blocking filter'' (via Lyman limit absorption) to
eliminate all FUV emission from the quasar. This will allow us to
carry out a deep search for FUV emission from the lower redshift DLA,
shortward of the Lyman limit of the higher redshift absorber. The
unique filter set and high spatial resolution afforded by WFC3/UVIS
will then enable us to directly image the lower redshift DLA and thus
estimate its size, star- formation rate and impact parameter from the
QSO sightline. We propose to observe a sample of 20 sightlines,
selected primarily from the SDSS database, requiring a total of 40 HST
orbits. The observations will allow us to determine the first FUV
luminosity function of high redshift DLA galaxies and to correlate the
DLA galaxy properties with the ISM characteristics inferred from
standard absorption-line analysis to significantly improve our
understanding of the general DLA population.

WFC3/UVIS 11594

A WFC3 Grism Survey for Lyman Limit Absorption at z=2

We propose to conduct a spectroscopic survey of Lyman limit absorbers
at redshifts 1.8 z 2.5, using WFC3 and the G280 grism. This
proposal intends to complete an approved Cycle 15 SNAP program
(10878), which was cut short due to the ACS failure. We have selected
64 quasars at 2.3 z 2.6 from the Sloan Digital Sky Survey
Spectroscopic Quasar Sample, for which no BAL signature is found at
the QSO redshift and no strong metal absorption lines are present at z
2.3 along the lines of sight. The survey has three main
observational goals. First, we will determine the redshift frequency
dn/dz of the LLS over the column density range 16.0 log(NHI) 20.3
cm^-2. Second, we will measure the column density frequency
distribution f(N) for the partial Lyman limit systems (PLLS) over the
column density range 16.0 log(NHI) 17.5 cm^-2. Third, we will
identify those sightlines which could provide a measurement of the
primordial D/H ratio. By carrying out this survey, we can also help
place meaningful constraints on two key quantities of cosmological
relevance. First, we will estimate the amount of metals in the LLS
using the f(N), and ground based observations of metal line
transitions. Second, by determining f(N) of the PLLS, we can constrain
the amplitude of the ionizing UV background at z~2 to a greater
precision. This survey is ideal for a snapshot observing program,
because the on-object integration times are all well below 30 minutes,
and follow-up observations from the ground require minimal telescope
time due to the QSO sample being bright.

WFC3/ACS/IR 11584

Resolving the Smallest Galaxies with ACS

An order of magnitude more dwarf galaxies are expected to inhabit the
Local Group, based on currently accepted galaxy formation models, than
have been observed. This discrepancy has been noted in environments
ranging from the field to rich clusters, with evidence emerging that
lower density regions contain fewer dwarfs per giant than higher
density regions, in further contrast to model predictions. However,
there is no complete census of the faintest dwarf galaxies in any
environment. The discovery of the smallest and faintest dwarfs is
hampered by the limitations in detecting such compact or low surface
brightness galaxies, and this is compounded by the great difficulty in
determining accurate distances to, or ascertaining group membership
for, such faint objects. The M81 group provides a powerful means for
establishing membership for faint galaxies in a low density region.
With a distance modulus of 27.8, the tip of the red giant branch
(TRGB) appears at I ~ 24, just within the reach of ground based
surveys. We have completed a 65 square degree survey in the region
around M81 with the CFHT/MegaCam. Half of our survey was completed
before Cycle 16 and we were awarded time with WFPC2 to observe 15 new
candidate dwarf galaxy group members in F606W and F814W bands in order
to construct color-magnitude diagrams from which to measure accurate
TRGB distances and determine star formation and metallicity histories.
The data obtained show that 8 - 9 of these objects are galaxies at the
same distance as M81. In completing our survey, we have discovered an
additional 8 candidate galaxies we propose to image with ACS in order
to measure TRGB distances and establish membership. We also wish to
re-observe our smallest candidate group member and a tidal dwarf
candidate with deeper observations made possible with ACS. Once
membership has been established for this second set of candidates, we
will have a complete census of the dwarf galaxy population in the M8
group to M_r ~ -10, allowing us to obtain a firm measurement of the
luminosity function faint-end slope, and, combined with previous HST
data, to provide a complete inventory of the age and abundance
properties for the collapsed core of the M81 group.

WFC3/UVIS 11565

A Search for Astrometric Companions to Very Low-Mass, Population II
Stars

We propose to carry out a Snapshot search for astrometric companions
in a subsample of very low-mass, halo subdwarfs identified within 120
parsecs of the Sun. These ultra-cool M subdwarfs are local
representatives of the lowest-mass H burning objects from the Galactic
Population II. The expected 3-4 astrometric doubles that will be
discovered will be invaluable in that they will be the first systems
from which gravitational masses of metal-poor stars at the bottom of
the main sequence can be directly measured.

NIC2/WFC3/IR 11219

Active Galactic Nuclei in Nearby Galaxies: A New View of the Origin of
the Radio-Loud Radio- Quiet Dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type
galaxies (drawn from a complete radio selected sample) we have found
evidence that the radio-loud/radio-quiet dichotomy is directly
connected to the structure of the inner regions of their host galaxies
in the following sense: [1] Radio-loud AGN are associated with
galaxies with shallow cores in their light profiles [2] Radio-quiet
AGN are only hosted by galaxies with steep cusps. Since the brightness
profile is determined by the galaxy's evolution, through its merger
history, our results suggest that the same process sets the AGN
flavor. This provides us with a novel tool to explore the co-evolution
of galaxies and supermassive black holes, and it opens a new path to
understand the origin of the radio-loud/radio-quiet AGN dichotomy.
Currently our analysis is statistically incomplete as the brightness
profile is not available for 82 of the 116 targets. Most galaxies were
not observed with HST, while in some cases the study is obstructed by
the presence of dust features. We here propose to perform an infrared
NICMOS snapshot survey of these 82 galaxies. This will enable us to i)
test the reality of the dichotomic behavior in a substantially larger
sample; ii) extend the comparison between radio-loud and radio-quiet
AGN to a larger range of luminosities.

WFC3/IR 11208

The Co-Evolution of Spheroids and Black Holes in the Last Six Billion
Years

The masses of giant black holes are correlated with the luminosities,
masses, and velocity dispersions of the bulges of their host galaxies.
This empirical correlation of phenomena on widely different scales
(from pcs to kpcs) suggests that the formation and evolution of
galaxies and central black holes are closely linked. In Cycle 13, we
have started a campaign to map directly the co-evolution of spheroids
and black-holes by measuring in observationally favorable redshift
windows the empirical correlations connecting their properties. By
focusing on Seyfert 1s, where the nucleus and the stars contribute
comparable fractions of total light, black hole mass and bulge
dispersion are obtained from Keck spectroscopy. HST is required for
accurate measurement of the non-stellar AGN continuum, the morphology
of the galaxy, and the structural parameters of the bulge. The results
at z=0.36 indicate a surprisingly fast evolution of bulges in the past
4 Gyrs (significant at the 95%CL), in the sense that bulges were
significantly smaller for a given black hole mass. Also, the large
fraction of mergers and disturbed galaxies (4+2 out of 20) identifies
gas-rich mergers as the mechanisms responsible for bulge-growth. Going
to higher redshift - where evolutionary trends should be stronger - is
needed to confirm these tantalizing results. We propose therefore to
push our investigation to the next suitable redshift window z=0.57
(lookback-time 6 Gyrs). Fifteen objects are the minimum number
required to map the evolution of the empirical correlations between
bulge properties and black-hole mass, and to achieve a conclusive
detection of evolution (99%CL).

WFC3/IR 11189

Probing the Early Universe with GRBs

Cosmology is beginning to constrain the nature of the earliest stars
and galaxies to form in the Universe, but direct observation of
galaxies at z6 remains highly challenging due to their scarcity,
intrinsically small size, and high luminosity distance. GRB
afterglows, thanks to their extreme luminosities, offer the
possibility of circumventing these normal constraints by providing
redshifts and spectral information which couldn't be obtained through
direct observation of the host galaxies themselves. In addition, the
association of GRBs with massive stars means that they are an
indicator of star formation, and that their hosts are likely
responsible for a large proportion of the ionizing radiation during
that era. Our collaboration is conducting a campaign to rapidly
identify and study candidate very high redshift bursts, bringing to
bear a network of 2, 4 and 8m telescopes with near-IR instrumentation.
Swift has proven capable of detecting faint, distant GRBs, and
reporting accurate positions for many bursts in near real-time. Here
we propose to continue our HST program of targeting GRBs at z~6 and
above. HST is crucial to this endeavor, allowing us (a) to
characterize the basic properties, such as luminosity and color, and
in some cases morphologies, of the hosts, which is essential to
understanding these primordial galaxies and their relationship to
other galaxy populations; and (b) to monitor the late time afterglows
and hence compare them to lower-z bursts and test the use of GRBs as
standard candles.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12203 - GSAcq(1,2,1) at 057/22:59:43z and REAcq(1,2,1) at
057/23:36:14z both acquired fine lock backup on FGS 1 due to scan step
limit exceeded on FGS 2

Observations possibly affected: WFC3 - 147 148, proposal ID# 11219

12204 - GSAcq(1,2,1) scheduled at 059/22:14:49z resulted in fine lock
backup (2,0,2) due to scan step limit exceeded on FGS 1.

Observations possibly affected: COS 105 - 109 proposal ID#11687, WFC3
1 proposal ID# 11929

12205 - REAcq(1,2,1) scheduled at 060/06:09:49z required multiple
attempts to achieve Coarse Track Data Valid.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 31 31
FGS REAcq 19 19
OBAD with Maneuver 21 21

SIGNIFICANT EVENTS: (None)