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 (Z<5% 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 (z>1). 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

6.5<z<8.8 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 z>2 Damped Lyman Alpha

Systems

We propose to directly image the star-forming regions of z>2 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

z>6 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)