Daily Report #4493

Notice: Due to the conversion of some ACS WFC or HRC observations into
WFPC2, or NICMOS observations after the loss of ACS CCD science
capability in January, there may be an occasional discrepancy between
a proposal's listed (and correct) instrument usage and the abstract
that follows it.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT***** # 4493

PERIOD COVERED: UT November 20,21,22,23,24,25, 2007 (DOY
324,325,326,327,328,329)

OBSERVATIONS SCHEDULED

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 DARKs. 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.

WFPC2 11289

SL2S: The Strong Lensing Legacy Survey

Recent systematic surveys of strong galaxy-galaxy lenses {CLASS,
SLACS, GOODS, etc.} are producing spectacular results for galaxy
masses roughly below a transition mass M~10^13 Mo. The observed lens
properties and their evolution up to z~0.2, consistent with numerical
simulations, can be described by isothermal elliptical potentials. In
contrast, modeling of giant arcs in X-ray luminous clusters {halo
masses M ~10^13 Mo} favors NFW mass profiles, suggesting that dark
matter halos are not significantly affected by baryon cooling. Until
recently, lensing surveys were neither deep nor extended enough to
probe the intermediate mass density regime, which is fundamental for
understanding the assembly of structures. The CFHT Legacy Survey now
covers 125 square degrees, and thus offers a large reservoir of strong
lenses probing a large range of mass densities up to z~1. We have
extracted a list of 150 strong lenses using the most recent CFHTLS
data release via automated procedures. Following our first SNAPSHOT
proposal in cycle 15, we propose to continue the Hubble follow-up
targeting a larger list of 130 lensing candidates. These are
intermediate mass range candidates {between galaxies and clusters}
that are selected in the redshift range of 0.2-1 with no a priori
X-ray selection. The HST resolution is necessary for confirming the
lensing candidates, accurate modeling of the lenses, and probing the
total mass concentration in galaxy groups up to z~1 with the largest
unbiased sample available to date.

ACS/SBC 11225

The Wavelength Dependence of Accretion Disk Structure

We can now routinely measure the size of quasar accretion disks using
gravitational microlensing of lensed quasars. The next step to testing
accretion disk models is to measure the size of accretion disks as a
function of wavelength, particularly at the UV and X-ray wavelengths
that should probe the inner, strong gravity regime. Here we focus on
two four-image quasar lenses that already have optical {R band} and
X-ray size measurements using microlensing. We will combine the HST
observations with ground-based monitoring to measure the disk size as
a function of wavelength from the near-IR to the UV. We require HST to
measure the image flux ratios in the ultraviolet continuum near the
Lyman limit of the quasars. The selected targets have estimated black
hole masses that differ by an order of magnitude, and we should find
wavelength scalings for the two systems that are very different
because the Blue/UV wavelengths should correspond to parts of the disk
near the inner edge for the high mass system but not in the low mass
system. The results will be modeled using a combination of simple thin
disk models and complete relativistic disk models. While requiring
only 18 orbits, success for one system requires observations in both
Cycles 16 and 17.

WFPC2 11222

Direct Detection and Mapping of Star Forming Regions in Nearby,
Luminous Quasars

We propose to carry out narrow-band emission line imaging observations
of 8 quasars at z=0.05-0.15 with the WFPC2 ramp filters and with the
NICMOS narrow-band filters. We will obtain images in the [O II], [O
III], H-beta, and Pa-alpha emission line bands to carry out a series
of diagnostic tests aimed at detecting and mapping out star-forming
regions in the quasar host galaxies. This direct detection of
star-forming regions will confirm indirect indications for star
formation in quasar host galaxies. It will provide a crucial test for
models of quasar and galaxy evolution, that predict the co-existence
of starbursts and "monsters" and will solve the puzzle of why
different indicators of star formation give contradictory results. A
secondary science goal is to assess suggested correlations between
quasar luminosity and the size of the narrow-line region.

WFPC2 11216

HST / Chandra Monitoring of a Dramatic Flare in the M87 Jet

As the nearest galaxy with an optical jet, M87 affords an unparalleled
opportunity to study extragalactic jet phenomena at the highest
resolution. During 2002, HST and Chandra monitoring of the M87 jet
detected a dramatic flare in knot HST-1 located ~1" from the nucleus.
Its optical brightness eventually increased seventy-fold and peaked in
2005; the X- rays show a similarly dramatic outburst. In both bands
HST-1 is still extremely bright and greatly outshines the galaxy
nucleus. To our knowledge this is the first incidence of an optical or
X-ray outburst from a jet region which is spatially distinct from the
core source -- this presents an unprecedented opportunity to study the
processes responsible for non- thermal variability and the X-ray
emission. We propose five epochs of HST/WFPC2 flux monitoring during
Cycle 16, as well as seven epochs of Chandra/ACIS observation {5ksec
each, six Chandra epochs contemporary with HST}. At two of the
HST/WFPC2 epochs we also gather spectral information, and at one epoch
we will map the magnetic field structure. The results of this
investigation are of key importance not only for understanding the
nature of the X-ray emission of the M87 jet, but also for
understanding flares in blazar jets, which are highly variable, but
where we have never before been able to resolve the flaring region in
the optical or X-rays. These new observations will allow us to track
the decay phase of the giant flare, and study smaller secondary flares
such as seen late in 2006. Ultimately we will test synchrotron
emission models for the X-ray outburst, constrain particle
acceleration and loss timescales, and study the jet dynamics
associated with this flaring component.

FGS 11211

An Astrometric Calibration of Population II Distance Indicators

In 2002 HST produced a highly precise parallax for RR Lyrae. That
measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a
useful result, judged by the over ten refereed citations each year
since. It is, however, unsatisfactory to have the direct,
parallax-based, distance scale of Population II variables based on a
single star. We propose, therefore, to obtain the parallaxes of four
additional RR Lyrae stars and two Population II Cepheids, or W Vir
stars. The Population II Cepheids lie with the RR Lyrae stars on a
common K-band Period-Luminosity relation. Using these parallaxes to
inform that relationship, we anticipate a zero-point error of 0.04
magnitude. This result should greatly strengthen confidence in the
Population II distance scale and increase our understanding of RR
Lyrae star and Pop II Cepheid astrophysics.

WEPC2 11196

An Ultraviolet Survey of Luminous Infrared Galaxies in the Local
Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
Luminous Infrared Galaxies {LIRGs} are primarily interacting or
merging disk galaxies undergoing starbursts and creating/fueling
central AGN. We propose far {ACS/SBC/F140LP} and near {WFPC2/PC/F218W}
UV imaging of a sample of 27 galaxies drawn from the complete IRAS
Revised Bright Galaxy Sample {RBGS} LIRGs sample and known, from our
Cycle 14 B and I-band ACS imaging observations, to have significant
numbers of bright {23 B 21 mag} star clusters in the central 30
arcsec. The HST UV data will be combined with previously obtained HST,
Spitzer, and GALEX images to {i} calculate the ages of the clusters as
function of merger stage, {ii} measure the amount of UV light in
massive star clusters relative to diffuse regions of star formation,
{iii} assess the feasibility of using the UV slope to predict the far-
IR luminosity {and thus the star formation rate} both among and within
IR-luminous galaxies, and {iv} provide a much needed catalog of
rest-frame UV morphologies for comparison with rest-frame UV images of
high-z LIRGs and Lyman Break Galaxies. These observations will achieve
the resolution required to perform both detailed photometry of compact
structures and spatial correlations between UV and redder wavelengths
for a physical interpretation our IRX-Beta results. The HST UV data,
combined with the HST ACS, Spitzer, Chandra, and GALEX observations of
this sample, will result in the most comprehensive study of luminous
starburst galaxies to date.

WFPC2 11178

Probing Solar System History with Orbits, Masses, and Colors of
Transneptunian Binaries

The recent discovery of numerous transneptunian binaries {TNBs} opens
a window into dynamical conditions in the protoplanetary disk where
they formed as well as the history of subsequent events which sculpted
the outer Solar System and emplaced them onto their present day
heliocentric orbits. To date, at least 47 TNBs have been discovered,
but only about a dozen have had their mutual orbits and separate
colors determined, frustrating their use to investigate numerous
important scientific questions. The current shortage of data
especially cripples scientific investigations requiring statistical
comparisons among the ensemble characteristics. We propose to obtain
sufficient astrometry and photometry of 23 TNBs to compute their
mutual orbits and system masses and to determine separate primary and
secondary colors, roughly tripling the sample for which this
information is known, as well as extending it to include systems of
two near-equal size bodies. To make the most efficient possible use of
HST, we will use a Monte Carlo technique to optimally schedule our
observations.

WFPC2 11176

Location and the Origin of Short Gamma-Ray Bursts

During the past decade extraordinary progress has been made in
determining the origin of long-duration gamma-ray bursts. It has been
conclusively shown that these objects derive from the deaths of
massive stars. Nonetheless, the origin of their observational cousins,
short-duration gamma-ray bursts {SGRBs} remains a mystery. While SGRBs
are widely thought to result from the inspiral of compact binaries,
this is a conjecture. A number of hosts of SGRBs have been identified,
and have been used by some to argue that SGRBs derive primarily from
an ancient population {~ 5 Gyr}; however, it is not known whether this
conclusion more accurately reflects selection biases or astrophysics.
Here we propose to employ a variant of a technique that we pioneered
and used to great effect in elucidating the origins of long-duration
bursts. We will examine the degree to which SGRB locations trace the
red or blue light of their hosts, and thus old or young stellar
populations. This approach will allow us to study the demographics of
the SGRB population in a manner largely free of the distance dependent
selection effects which have so far bedeviled this field, and should
give direct insight into the age of the SGRB progenitor population.

ACS/SBC WFPC2 11175

UV Imaging to Determine the Location of Residual Star Formation in
Galaxies Recently Arrived on the Red Sequence

We have identified a sample of low-redshift {z = 0.04 - 0.10} galaxies
that are candidates for recent arrival on the red sequence. They have
red optical colors indicative of old stellar populations, but blue
UV-optical colors that could indicate the presence of a small quantity
of continuing or very recent star formation. However, their spectra
lack the emission lines that characterize star-forming galaxies. We
propose to use ACS/SBC to obtain high- resolution imaging of the UV
flux in these galaxies, in order to determine the spatial distribution
of the last episode of star formation. WFPC2 imaging will provide B,
V, and I photometry to measure the main stellar light distribution of
the galaxy for comparison with the UV imaging, as well as to measure
color gradients and the distribution of interstellar dust. This
detailed morphological information will allow us to investigate the
hypothesis that these galaxies have recently stopped forming stars and
to compare the observed distribution of the last star formation with
predictions for several different mechanisms that may quench star
formation in galaxies.

NIC2 11143

NICMOS imaging of submillimeter galaxies with CO and PAH redshifts

We propose to obtain F110W and F160W imaging of 10 z~2.4 submillimeter
galaxies {SMGs} whose optical redshifts have been confirmed by the
detection of millimeter CO and/or mid-infrared PAH emission. With the
4000A break falling within/between the two imaging filters, we will be
able to study these sources' spatially resolved stellar populations
{modulo extinction} in the rest-frame optical. SMGs' large
luminosities appear to be due largely to merger-triggered starbursts;
high-resolution NICMOS imaging will help us understand the stellar
masses, mass ratios, and other properties of the merger progenitors,
valuable information in the effort to model the mass assembly history
of the universe.

WFPC2 11134

WFPC2 Tidal Tail Survey: Probing Star Cluster Formation on the Edge

The spectacular HST images of the interiors of merging galaxies such
as the Antennae and NGC 7252 have revealed rich and diverse
populations of star clusters created over the course of the
interaction. Intriguingly, our WFPC2 study of tidal tails in these and
other interacting pairs has shown that star cluster birth in the tails
does not follow a similarly straightforward evolution. In fact,
cluster formation in these relatively sparse environments is not
guaranteed -- only one of six tails in our initial study showed
evidence for a significant population of young star clusters. The tail
environment thus offers the opportunity to probe star cluster
formation on the edge of the physical parameter space {e.g., of
stellar and gas mass, density, and pressure} that permits it to occur.
We propose to significantly extend our pilot sample of optically
bright, gas-rich tidal tails by a factor of 4 in number to include a
more diverse population of tails, encompassing major and minor
mergers, gas-rich and gas-poor tails, as well as early, late, and
merged interaction stages. With 21 orbits of HST WFPC2 imaging in the
F606W and F814W filters, we can identify, roughly age-date, and
measure sizes of star clusters to determine what physical parameters
affect star cluster formation. WFPC2 imaging has been used effectively
in our initial study of four mergers, and it will be possible in this
program to reach similar limits of Mv=-8.5 for each of 16 more tails.
With the much larger sample we expect to isolate which factors, such
as merger stage, HI content, and merger mass ratio, drive the
formation of star clusters.

WFPC2 11130

AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge
Paradigm, Part II

The recent progress in the study of central black holes in galactic
nuclei has led to a general consensus that supermassive {10^6-10^9
solar mass} black holes are closely connected with the formation and
evolutionary history of large galaxies, especially their bulge
component. Two outstanding issues, however, remain unresolved. Can
central black holes form in the absence of a bulge? And does the mass
function of central black holes extend below 10^6 solar masses?
Intermediate-mass black holes {10^6 solar masses}, if they exist, may
offer important clues to the nature of the seeds of supermassive black
holes. Using the SDSS, our group has successfully uncovered a new
population of AGNs with intermediate-mass black holes that reside in
low-luminosity galaxies. However, very little is known about the
detailed morphologies or structural parameters of the host galaxies
themselves, including the crucial question of whether they have bulges
or not. Surprisingly, the majority of the targets of our Cycle 14
pilot program have structural properties similar to dwarf elliptical
galaxies. The statistics from this initial study, however, are really
too sparse to reach definitive conclusions on this important new class
of black holes. We wish to extend this study to a larger sample, by
using the Snapshot mode to obtain WFPC2 F814W images from a parent
sample of 175 AGNs with intermediate-mass black holes selected from
our final SDSS search. We are particularly keen to determine whether
the hosts contain bulges, and if so, how the fundamental plane
properties of the host depend on the mass of their central black
holes. We will also investigate the environment of this unique class
of AGNs.

WFPC2 11128

Time Scales Of Bulge Formation In Nearby Galaxies

Traditionally, bulges are thought to fit well into galaxy formation
models of hierarchical merging. However, it is now becoming well
established that many bulges formed through internal, secular
evolution of the disk rather than through mergers. We call these
objects pseudobulges. Much is still unknown about pseudobulges, the
most pressing questions being: How, exactly, do they build up their
mass? How long does it take? And, how many exist? We are after an
answer to these questions. If pseudobulges form and evolve over longer
periods than the time between mergers, then a significant population
of pseudobulges is hard to explain within current galaxy formation
theories. A pseudobulge indicates that a galaxy has most likely not
undergone a major merger since the formation of the disk. The ages of
pseudobulges give us an estimate for the time scale of this quiescent
evolution. We propose to use 24 orbits of HST time to complete UBVIH
imaging on a sample of 33 nearby galaxies that we have observed with
Spitzer in the mid-IR. These data will be used to measure spatially
resolved stellar population parameters {mean stellar age, metallicity,
and star formation history}; comparing ages to star formation rates
allows us to accurately constrain the time scale of pseudobulge
formation. Our sample of bulges includes both pseudo- and classical
bulges, and evenly samples barred and unbarred galaxies. Most of our
sample is imaged, 13 have complete UBVIH coverage; we merely ask to
complete missing observations so that we may construct a uniform
sample for studying bulge formation. We also wish to compare the
stellar population parameters to a variety of bulge and global galaxy
properties including star formation rates, dynamics, internal bulge
morphology, structure from bulge-disk decompositions, and gas content.
Much of this data set is already or is being assembled. This will
allow us to derive methods of pseudobulge identification that can be
used to accurately count pseudobulges in large surveys. Aside from our
own science goals, we will present this broad set of data to the
community. Thus, we waive proprietary periods for all observations.

WFPC2 11126

Resolving the Smallest Galaxies

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. One
possible explanation for this involves the effects of reionization on
the forming galaxies and naturally explains both the dearth of dwarf
galaxies and the apparent environmental dependence. However, before
such theories can be fully tested, we require a better understanding
of the distribution of dwarf galaxies. Currently, 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 faint and 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 unique means for
establishing membership for galaxies in a low density region complete
to magnitudes as faint as M_R ~ -7. 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 currently have surveyed a 30
square degree region around M81 with the CFHT/Megacam. From these
images we have detected 15 new candidate dwarf galaxies. We propose to
use the HST with WFPC2 to image these 15 galaxies in F606W and F814W
bands in order to construct a color-magnitude diagram down to I = 25.5
from which to measure accurate TRGB distances to these candidate
galaxies and determine star formation and metallicity histories. The
overall project will provide a survey of the dwarf galaxies in the M81
group environment with unprecedented completeness to a limit of M_R
-7.

ACS/SBC 11109

Characterization of the UV absorption feature in asteroid {1} Ceres

We propose to obtain the UV spectrum of asteroid {1} Ceres from 120 nm
to 200 nm with ACS/SBC objective prism to characterize the broad and
deep absorption feature within this wavelength range as reported by
ACS observations of Ceres in 2003/04 {Li et al. 2006}. Our scientific
goals include, 1} to characterize the absorption band, 2} to determine
the origin of this spectral feature and constrain the surface
composition of Ceres, and 3} to understand the albedo and color
features on Ceres. HST is the only observatory currently capable of
obtaining spectroscopy in this wavelength range. This observation will
help improve our knowledge about this largest and oldest asteroid, and
support the planning of the upcoming NASA Discovery Program mission,
Dawn, orbiting asteroids Vesta and Ceres.

WFPC2 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey
of a sample of 125 very X-ray luminous clusters in the redshift range
0.3-0.7. As demonstrated by the 25 snapshots obtained so far in
Cycle14 and Cycle15 these systems frequently exhibit strong
gravitational lensing as well as spectacular examples of violent
galaxy interactions. The proposed observations will provide important
constraints on the cluster mass distributions, the physical nature of
galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set
of optically bright, lensed galaxies for further 8-10m spectroscopy.
All of our primary science goals require only the detection and
characterization of high-surface-brightness features and are thus
achievable even at the reduced sensitivity of WFPC2. Because of their
high redshift and thus compact angular scale our target clusters are
less adversely affected by the smaller field of view of WFPC2 than
more nearby systems. Acknowledging the broad community interest in
this sample we waive our data rights for these observations. Due to a
clerical error at STScI our approved Cycle15 SNAP program was barred
from execution for 3 months and only 6 observations have been
performed to date - reinstating this SNAP at Cycle16 priority is of
paramount importance to reach meaningful statistics.

NIC2 11101

The Relevance of Mergers for Fueling AGNs: Answers from QSO Host
Galaxies

The majority of QSOs are known to reside in centers of galaxies that
look like ellipticals. Numerical simulations have shown that remnants
of galaxy mergers often closely resemble elliptical galaxies. However,
it is still strongly debated whether the majority of QSO host galaxies
are indeed the result of relatively recent mergers or whether they are
completely analogous to inactive ellipticals to which nothing
interesting has happened recently. To address this question, we
recently obtained deep HST ACS images for five QSO host galaxies that
were classified morphologically as ellipticals {GO-10421}. This pilot
study revealed striking signs of tidal interactions such as ripples,
tidal tails, and warped disks that were not detected in previous
studies. Our observations show that at least some "elliptical" QSO
host galaxies are the products of relatively recent merger events
rather than old galaxies formed at high redshift. However, the
question remains whether the host galaxies of classical QSOs are truly
distinct from inactive ellipticals and whether there is a connection
between the merger events we detect and the current nuclear activity.
We must therefore place our results into a larger statistical context.
We are currently conducting an HST archival study of inactive
elliptical galaxies {AR-10941} to form a control sample. We now
propose to obtain deep HST/WFPC2 images of 13 QSOs whose host galaxies
are classified as normal ellipticals. Comparing the results for both
samples will help us determine whether classical QSOs reside in normal
elliptical galaxies or not. Our recent pilot study of five QSOs
indicates that we can expect exciting results and deep insights into
the host galaxy morphology also for this larger sample of QSOs. A
statistically meaningful sample will help us determine the true
fraction of QSO hosts that suffered strong tidal interactions and
thus, whether a merger is indeed a requirement to trigger nuclear
activity in the most luminous AGNs. In addition to our primary science
observations with WFPC2, we will obtain NICMOS3 parallel observations
with the overall goal to select and characterize galaxy populations at
high redshifts. The imaging will be among the deepest NICMOS images:
These NICMOS images are expected to go to a limit a little over 1
magnitude brighter than HUDF-NICMOS data, but over 13 widely separated
fields, with a total area about 1.5 times larger than HUDF-NICMOS.
This separation means that the survey will tend to average out effects
of cosmic variance. The NICMOS3 images will have sufficient resolution
for an initial characterization of galaxy morphologies, which is
currently one of the most active and promising areas in approaching
the problem of the formation of the first massive galaxies. The depth
and area coverage of our proposed NICMOS observations will also allow
a careful study of the mass function of galaxies at these redshifts.
This provides a large and unbiased sample, selected in terms of
stellar mass and unaffected by cosmic variance, to study the on-going
star formation activity as a function of mass {i.e. integrated star
formation} at this very important epoch.

NIC3 11082

NICMOS Imaging of GOODS: Probing the Evolution of the Earliest Massive
Galaxies, Galaxies Beyond Reionization, and the High Redshift Obscured
Universe

(uses ACS/SBC and WFPC2)

Deep near-infrared imaging provides the only avenue towards
understanding a host of astrophysical problems, including: finding
galaxies and AGN at z 7, the evolution of the most massive galaxies,
the triggering of star formation in dusty galaxies, and revealing
properties of obscured AGN. As such, we propose to observe 60 selected
areas of the GOODS North and South fields with NICMOS Camera 3 in the
F160W band pointed at known massive M 10^11 M_0 galaxies at z 2
discovered through deep Spitzer imaging. The depth we will reach {26.5
AB at 5 sigma} in H_160 allows us to study the internal properties of
these galaxies, including their sizes and morphologies, and to
understand how scaling relations such as the Kormendy relationship
evolved. Although NIC3 is out of focus and under sampled, it is
currently our best opportunity to study these galaxies, while also
sampling enough area to perform a general NIR survey 1/3 the size of
an ACS GOODS field. These data will be a significant resource,
invaluable for many other science goals, including discovering high
redshift galaxies at z 7, the evolution of galaxies onto the Hubble
sequence, as well as examining obscured AGN and dusty star formation
at z 1.5. The GOODS fields are the natural location for HST to
perform a deep NICMOS imaging program, as extensive data from space
and ground based observatories such as Chandra, GALEX, Spitzer, NOAO,
Keck, Subaru, VLT, JCMT, and the VLA are currently available for these
regions. Deep high-resolution near-infrared observations are the one
missing ingredient to this survey, filling in an important gap to
create the deepest, largest, and most uniform data set for studying
the faint and distant universe. The importance of these images will
increase with time as new facilities come on line, most notably WFC3
and ALMA, and for the planning of future JWST observations.

WFPC2 11035

Photometric Zero Points Closeout

Updated zero points will be obtained by observing NGC 2419 for which
extensive BVRI ground based observations exist, and the field in 47
Tuc used for frequent monitoring of ACS. For NGC 2419 emphasis is
given to repeating observations obtained in earlier epochs, and to
covering filters near standard BVRI. For 47 Tuc emphasis is given to
covering a large set of broadband filters from F300W through F850LP to
maximise transformation capabilities between filters of WFPC2 and
ACS.

WFPC2 10798

Dark Halos and Substructure from Arcs & Einstein Rings

The surface brightness distribution of extended gravitationally lensed
arcs and Einstein rings contains super-resolved information about the
lensed object, and, more excitingly, about the smooth and clumpy mass
distribution of the lens galaxies. The source and lens information can
non-parametrically be separated, resulting in a direct "gravitational
image" of the inner mass-distribution of cosmologically-distant
galaxies {Koopmans 2005; Koopmans et al. 2006 [astro-ph/0601628]}.
With this goal in mind, we propose deep HST ACS-F555W/F814W and
NICMOS-F160W WFC imaging of 20 new gravitational-lens systems with
spatially resolved lensed sources, of the 35 new lens systems
discovered by the Sloan Lens ACS Survey {Bolton et al. 2005} so far,
15 of which are being imaged in Cycle-14. Each system has been
selected from the SDSS and confirmed in two time- efficient HST-ACS
snapshot programs {cycle 13&14}. High-fidelity multi-color HST images
are required {not delivered by the 420s snapshots} to isolate these
lensed images {properly cleaned, dithered and extinction-corrected}
from the lens galaxy surface brightness distribution, and apply our
"gravitational maging" technique. Our sample of 35 early-type lens
galaxies to date is by far the largest, still growing, and most
uniformly selected. This minimizes selection biases and small-number
statistics, compared to smaller, often serendipitously discovered,
samples. Moreover, using the WFC provides information on the field
around the lens, higher S/N and a better understood PSF, compared with
the HRC, and one retains high spatial resolution through drizzling.
The sample of galaxy mass distributions - determined through this
method from the arcs and Einstein ring HST images - will be studied
to: {i} measure the smooth mass distribution of the lens galaxies
{dark and luminous mass are separated using the HST images and the
stellar M/L values derived from a joint stellar-dynamical analysis of
each system}; {ii} quantify statistically and individually the
incidence of mass-substructure {with or without obvious luminous
counter- parts such as dwarf galaxies}. Since dark-matter substructure
could be more prevalent at higher redshift, both results provide a
direct test of this prediction of the CDM hierarchical
structure-formation model.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11076 - GSacq(1,3,1) failed, Scan Step Limit exceeded on FGS 1

GSACQ(1,3,1) at 326/06:01:11 failed due to scan step limit exceeded on
FGS 1 while vehicle was LOS. No ESB messages were received, #44
commands did not update from their values prior to LOS.

11077 - REacq(1,2,2) failed to RGA Hold

At AOS at 326/12:16:45, REacq(1,2,2) scheduled at 11:46:45 had failed
to RGA hold due to receiving QF1STOPF on FGA 1. OBAD2 had RSS value of
2.44 arcseconds.

11078 - GSacq(1,2,1) failed, Search Radius Limit exceeded on FGS 1

GSacq(1,2,1) at 327/08:13:07 failed at 08:18:58 with search radius
limit exceeded on FGS 1. One 486 status buffer "A05" message (FGS
Coarse Track failed- search Radius Limit exceeded) was received. OBAD
prior to GSACQ had RSS error of 14.39 arcseconds.

11079 - GSacq(1,3,1) not attempted, Open Loop Timer expired

GSACQ(1,3,1) at 330/04:14:05 failed while vehicle was LOS, was not
attempted due to open loop timer expiration. 27 ESB messages were
received beginning at 04:11:31, see attached dump file.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

************************ SCHEDULED***** SUCCESSFUL

FGS GSacq**************** 43***************** 40
FGS REacq**************** 26***************** 25
OBAD with Maneuver ***** 134*************** 134

SIGNIFICANT EVENTS: (None)