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 # 4487
PERIOD
COVERED: UT November 09,10,11,12, 2007 (DOY 313,314,315,316)
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
11312
The
Local Cluster Substructure Survey {LoCuSS}: Deep Strong Lensing
Observations
with WFPC2
LoCuSS
is a systematic and detailed investigation of the mass,
substructure,
and thermodynamics of 100 X-ray luminous galaxy clusters
at
0.15<z<0.3. The primary goal is to test our recent suggestion that
this
population is dominated by dynamically immature disturbed clusters,
and
that the observed mass-temperature relation suffers strong
structural
segregation. If confirmed, this would represent a paradigm
shift
in our observational understanding of clusters, that were hitherto
believed
to be dominated by mature, undisturbed systems. We propose to
complete
our successful Cycle 15 program {SNAP:10881} which prior to
premature
termination had delivered robust weak-lensing detections in 17
clusters,
and candidate strongly-lensed arcs in 11 of these 17. These
strong
and weak lensing signals will give an accurate measure of the
total
mass and structure of the dark matter distribution that we will
subsequently
compare with X-ray and Sunyaev Zeldovich Effect
observables.
The broader applications of our project include 1} the
calibration
of mass-temperature and mass-SZE scaling relations which
will
be critical for the calibration of proposed dark energy
experiments,
and 2} the low redshift baseline study of the demographics
of
massive clusters to aid interpretation of future high redshift {z>1}
cluster
samples. To complete the all-important high resolution imaging
component
of our survey, we request deep WFPC2 observations of 20
clusters
through the F606W filter, for which wide-field weak-lensing
data
are already available from our Subaru imaging program. The
combination
of deep WFPC2 and Subaru data for these 20 clusters will
enable
us to achieve the science program approved by the Cycle 15 TAC.
WFPC2
11307
Completing
the ACS Nearby Galaxy Survey with WFPC2
We
are requesting 25 orbits of Director's Discretionary Time to complete
the
primary science goals of our highly-ranked ACS Nearby Galaxy Survey
Treasury
program {ANGST}. Our program lost ~2/3 of its orbits due to the
ACS
failure. Roughly half of these were restored as a result of an
appeal
to the Telescope Time Review Board which re-scoped the program.
The
Board's response to our appeal was explicit in terms of which
targets
were to be observed and how. We were directed to request
Director's
discretionary time for the components of the appeal which
were
not granted by the Review Board, but which were vital to the
success
of the program. The observing strategy for ANGST is two-fold: to
obtain
one deep field per galaxy which enables derivation of an accurate
ancient
star formation history, and to obtain radial tilings sufficient
for
recovering the full star formation history. The Review Board granted
WFPC2
observations for deep fields in 7 galaxies, but no time for radial
tilings.
However, recovering the full star formation history of a galaxy
is
not possible without additional radial coverage. We have searched the
archives
for observations which may be used in place of the tilings
{conceding
some of the Treasury goals, but providing significant
constraints
on the full star formation history}, and have identified
suitable
observations for all but two of the galaxies. Here we request
DD time
for radial tilings for those last two galaxies.
NIC3
11306
Direct
radius measurement of the Neptune-size transiting exoplanet
GJ436b
We
propose to measure the radius of the first transiting Neptune-class
extrasolar
planet, GJ 436b. The transits of this 22-Earth-mass planet
around
a nearby M dwarf were recently detected by our team. Ground-based
photometric
observations indicate a planet size compatible with a
Neptune-like
structure or an "Ocean Planet". A direct radius
determination
from an HST infrared lightcurve will provide a much more
direct
measurement of the radius and density of the planet. GJ 436b is
the
nearest known transiting exoplanet, as well as the smallest and
lightest,
by a large margin. The high planet-to-star contrast in the
infrared
make it very favorable for detailed studies. NICMOS 1-2 microns
observations,
in addition to measuring its size, may reveal water
absorption
from its outer atmosphere.
NIC2
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 flavour. 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 behaviour in a substantially larger sample; ii} extend
the
comparison between radio-loud and radio-quiet AGN to a larger range
of
luminosities.
ACS/SBC
11215
New
Sightlines for the Study of Intergalactic Helium: Dozens of
High-Confidence,
UV-Bright Quasars from SDSS/GALEX
The
reionization of IGM helium is thought to have occurred at redshifts
of
z=3 to 4. Detailed study of HeII Lyman-alpha absorption toward a
handful
of QSOs at 2.7<z<3.3 demonstrated the high potential of such IGM
probes,
but the critically small sample size limits confidence in
cosmological
inferences. The requisite unobscured sightlines to high-z
are
extremely rare, but SDSS provides 5800, z>3.1 QSOs potentially
suitable
for HeII studies. We've cross-correlated SDSS quasars with
GALEX
UV sources to obtain dozens of new, high confidence, candidate
sightlines
{z=3.1-4.9} potentially useful for detailed HeII studies with
HST.
We propose brief, 2-orbit reconnaissance ACS SBC prism exposures
toward
each of the best dozen new quasars, to definitively verify UV
flux
down to HeII. Our combined SDSS/GALEX selection insures a high
confirmation
rate, as the quasars are already known to be UV bright in
GALEX.
Our program will provide a statistical sample of HeII sightlines
extending
to high redshift, enabling future long exposure follow-up
spectra
with the SBC prism, or superb quality COS or STIS spectra after
SM4.
Stacks of our prism spectra will also directly yield ensemble
information.
Ultimately, the new sightlines will enable confident
measures
of the spectrum and evolution of the ionizing background, the
evolution
of HeII opacity, the epoch of helium reionization, and the
density
of IGM baryons.
FGS
11212
Filling
the Period Gap for Massive Binaries
The
current census of binaries among the massive O-type stars is
seriously
incomplete for systems in the period range from years to
millennia
because the radial velocity variations are too small and the
angular
separations too close for easy detection. Here we propose to
discover
binaries in this observational gap through a Faint Guidance
Sensor
SNAP survey of relatively bright targets listed in the Galactic O
Star
Catalog. Our primary goal is to determine the binary frequency
among
those in the cluster/association, field, and runaway groups. The
results
will help us assess the role of binaries in massive star
formation
and in the processes that lead to the ejection of massive
stars
from their natal clusters. The program will also lead to the
identification
of new, close binaries that will be targets of long term
spectroscopic
and high angular resolution observations to determine
their
masses and distances. The results will also be important for the
interpretation
of the spectra of suspected and newly identified binary
and
multiple systems.
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
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.
NIC1/NIC2
11204
Imaging
Circumstellar Disks and Envelopes around Proto-Brown Dwarfs
Using
the Spitzer Space Telescope, we have discovered two young brown
dwarfs
with Class I spectral energy distributions {i.e., proto-brown
dwarfs}.
We propose to perform broad-band NICMOS imaging of these Class
I
brown dwarfs to spatially resolve their circumstellar disks and
envelopes.
If successful, these data would comprise the first
measurements
of this kind for brown dwarfs and would provide fundamental
constraints
on models for the formation of brown dwarfs.
WFPC2
11202
The
Structure of Early-type Galaxies: 0.1-100 Effective Radii
The
structure, formation and evolution of early-type galaxies is still
largely
an open problem in cosmology: how does the Universe evolve from
large
linear scales dominated by dark matter to the highly non-linear
scales
of galaxies, where baryons and dark matter both play important,
interacting,
roles? To understand the complex physical processes
involved
in their formation scenario, and why they have the tight
scaling
relations that we observe today {e.g. the Fundamental Plane}, it
is
critically important not only to understand their stellar structure,
but
also their dark-matter distribution from the smallest to the largest
scales.
Over the last three years the SLACS collaboration has developed
a
toolbox to tackle these issues in a unique and encompassing way by
combining
new non-parametric strong lensing techniques, stellar
dynamics,
and most recently weak gravitational lensing, with
high-quality
Hubble Space Telescope imaging and VLT/Keck spectroscopic
data
of early-type lens systems. This allows us to break degeneracies
that
are inherent to each of these techniques separately and probe the
mass
structure of early-type galaxies from 0.1 to 100 effective radii.
The
large dynamic range to which lensing is sensitive allows us both to
probe
the clumpy substructure of these galaxies, as well as their
low-density
outer haloes. These methods have convincingly been
demonstrated,
by our team, using smaller pilot-samples of SLACS lens
systems
with HST data. In this proposal, we request observing time with
WFPC2
and NICMOS to observe 53 strong lens systems from SLACS, to obtain
complete
multi-color imaging for each system. This would bring the total
number
of SLACS lens systems to 87 with completed HST imaging and
effectively
doubles the known number of galaxy-scale strong lenses. The
deep
HST images enable us to fully exploit our new techniques, beat down
low-number
statistics, and probe the structure and evolution of
early-type
galaxies, not only with a uniform data-set an order of
magnitude
larger than what is available now, but also with a fully
coherent
and self-consistent methodological approach!
ACS/SBC
11199
A
Hard Look at Stellar Disks at the Epoch of Planet Formation
We
propose to use HST/ACS/SBC and Chandra/ACIS-S3 to observe the high
energy
fluxes of 4 stars surrounded by disks in the newly discovered
aggregate
25 Ori, the most populous 10 Myr group known within 500 pc.
Our
observations will cover the 1-25A and 1250-2000A bandpasses, and
will
complement our optical and Spitzer data for these objects, to
provide
essential input to physically-consistent models of disk
structure
and chemistry in the age range around 10 Myr, thought to be a
critical
period in the planet- forming process. We will be able to
determine
the Ne/O ratio and determine if the anomalous metal abundances
observed
in X-ray spectra of young stars are an evolutionary or an
environmental
effect. Our proposed observations will double the number
of
10 Myr old accreting stars with known high energy radiation fields,
and
will be the first FUV observations of low mass accreting stars in an
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
optimally
schedule our observations.
WFPC2
11170
UV
Imaging of the Martian
ACS
SBC UV imaging observations of Mars are proposed to study the
extended
hydrogen corona, with application to the escape of hydrogen and
the
history of water on Mars. These observations will be scheduled when
Mars
is distant from the Earth, so that a field of view of +/- 4-5 Mars
radii
can be obtained to image the full range of the highly extended
martian
hydrogen corona through its H Ly alpha emission. The
observations
will also be obtained when the Sun-Earth-Mars angle is
close
to 90 degrees, so that any asymmetry along the Mars-Sun line can
be
observed. The observed 2-dimensional brightness distribution will be
related
to local density using two existing radiative transfer codes,
and
the upward flux and velocity distributions will be determined by
comparison
with runs from an exospheric distribution model. These
observations,
combined with simultaneous Ly alpha observations by the
SPICAM
instrument on Mars Express from within the atmosphere, will
provide
the first tight constraints on the total escape flux and
importance
of nonthermal processes on the rate of escape.
WFPC2
11169
Collisions
in the Kuiper belt
For
most of the 15 year history of observations of Kuiper belt objects,
it
has been speculated that impacts must have played a major role in
shaping
the physical and chemical characteristics of these objects, yet
little
direct evidence of the effects of such impacts has been seen. The
past
18 months, however, have seen an explosion of major new discoveries
giving
some of the first insights into the influence of this critical
process.
From a diversity of observations we have been led to the
hypotheses
that: {1} satellite- forming impacts must have been common in
the
Kuiper belt; {2} such impacts led to significant chemical
modification;
and {3} the outcomes of these impacts are sufficiently
predictable
that we can now find and study these impact-derived systems
by
the chemical and physical attributes of both the satellites and the
primaries.
If our picture is correct, we now have in hand for the first
time
a set of incredibly powerful tools to study the frequency and
outcome
of collisions in the outer solar system. Here we propose three
linked
projects that would answer questions critical to the multiple
prongs
of our hypothesis. In these projects we will study the chemical
effects
of collisions through spectrophotometric observations of
collisionally
formed satellites and through the search for additional
satellites
around primaries with potential impact signatures, and we
will
study the physical effects of impacts through the examination of
tidal
evolution in proposed impact systems. The intensive HST program
that
we propose here will allow us to fully test our new hypotheses and
will
provide the ability to obtain the first extensive insights into
outer
solar system impact processes.
NIC2
11155
Dust
Grain Evolution in Herbig Ae Stars: NICMOS Coronagraphic Imaging
and
Polarimetry
We
propose to take advantage of the sensitive coronagraphic capabilities
of
NICMOS to obtain multiwavelength coronagraphic imaging and
polarimetry
of primordial dust disks around young intermediate-mass
stars
{Herbig Ae stars}, in order to advance our understanding of how
dust
grains are assembled into larger bodies. Because the polarization
of
scattered light is strongly dependent on scattering particle size and
composition,
coronagraphic imaging polarimetry with NICMOS provides a
uniquely
powerful tool for measuring grain properties in spatially
resolved
circumstellar disks. It is widely believed that planets form
via
the gradual accretion of planetesimals in gas-rich, dusty
circumstellar
disks, but the connection between this suspected process
and
the circumstellar disks that we can now observe around other stars
remains
very uncertain. Our proposed observations, together with
powerful
3-D radiative transfer codes, will enable us to quantitatively
determine
dust grain properties as a function of location within disks,
and
thus to test whether dust grains around young stars are in fact
growing
in size during the putative planet-formation epoch. HST imaging
polarimetry
of Herbig Ae stars will complement and extend existing
polarimetric
studies of disks around lower-mass T Tauri stars and debris
disks
around older main-sequence stars. When combined with these
previous
studies, the proposed research will help us establish the
influence
of stellar mass on the growth of dust grains into larger
planetesimals,
and ultimately to planets. Our results will also let us
calibrate
models of the thermal emission from these disks, a critical
need
for validating the properties of more distant disks inferred on the
basis
of spectral information alone.
WFPC2
11146
The
Role of Stellar Feedback in Galaxy Evolution
Stellar
feedback - the return of mass and energy from star formation to
the
interstellar medium - is one of the primary engines of galaxy
evolution.
Yet, the observational canvass of feedback is incomplete. We
propose
to investigate this fundamental aspect of star formation on one
local
actively star-forming galaxy, He2-10, selected to occupy an
unexplored
niche in the key parameter space of stellar mass. The WFPC2
narrow-band
observations in the light of H-beta, [OIII], H-alpha, and
[SII]
will: {1} discriminate the feedback-induced shock fronts from the
photoionized
regions; {2} map, and provide a complete census of, the
shocks
inside and around the starburst regions; and {3} measure the
energy
budget of the star-formation-produced shocks. These observations,
joined
by our previous data and studies on starbursts, will yield: {1}
the
efficiency of the feedback, i.e. the fraction of the star
formation's
mechanical energy transported out of the starburst volume
rather
than radiated away, in the dual-parameter space of host's stellar
mass
and star formation intensity; {2} the conditions under which
feedback
morphs from a localized process to a galactic scale mechanism.
The
high angular resolution of HST is crucial for separating the
spatially
narrow shock fronts {~10 pc=0.2" at 10 Mpc} from the more
extended
photoionization fronts. This project will provide the most
comprehensive
quantitative foundation of stellar feedback and a gauge
for
determining the role of feedback in the energetics, structure and
star
formation history of galaxies.
ACS/SBC
11116
Exploring
the Early FUV History of Cool Stars: Transition Regions at 30
Myr
Stellar
magnetic activity derives from the so-called "dynamo," a
hydromagnetic
interplay between overturning plasma motions and
differential
rotation in stars cool enough to support significant
surface
convection zones. The magnetic fields resulting from dynamo
action
are in turn are responsible for a wide range of high-energy
emissions,
including the spectacular outbursts called flares. Dynamo
powered
magnetic activity is not confined solely to stars, but also must
occur,
for example, in accretion disks of all descriptions, and in some
planets.
A great deal is known about magnetic activity in middle-aged G
dwarfs
like our Sun, thanks to its proximity. Less is known, however,
about
the much younger stars, newly emerged from the T-Tauri stage. Yet,
it
is during this phase that they reach the peak of their magnetic
activity,
and subsidiary influences, such as the impact of ionizing
radiation
and strong coronal winds on developing solar systems, also are
maximum.
One of the key missing ingredients in our current understanding
are
measurements of FUV emissions of such stars, to complement the
extensive
collections of coronal {1-10 MK} X-ray measurements,
particularly
from recent ROSAT, Chandra and XMM-Newton surveys. We
propose
to conduct sensitive ACS/SBC prism ultraviolet spectroscopy of
selected
fields in two young {30 Myr} Galactic clusters--IC 2391 and IC
2602--to
inventory the key C IV emission index {~0.1 MK} over a much
larger
and more diverse sample of coeval objects than has been possible
hitherto.
A key question is whether the FUV emissions also suffer the
"saturation"
and "super-saturation" at short rotation periods seen in
coronal
X-rays, or whether they continue to rise in the fastest rotating
stars.
The saturation behavior of the different temperature regimes
holds
important clues to the organization of the surface active regions
on
these very young stars, and should allow us to distinguish among
several
competing models.
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.
NIC3
11080
Exploring
the Scaling Laws of Star Formation
As
a variety of surveys of the local and distant Universe are
approaching
a full census of galaxy populations, our attention needs to
turn
towards understanding and quantifying the physical mechanisms that
trigger
and regulate the large-scale star formation rates {SFRs} in
galaxies.
WFPC2
11070
WFPC2
CYCLE 15 Standard Darks - part II
This
dark calibration program obtains dark frames every week in order to
provide
data for the ongoing calibration of the CCD dark current rate,
and
to monitor and characterize the evolution of hot pixels. Over an
extended
period these data will also provide a monitor of radiation
damage
to the CCDs.
NIC1
11057
Cycle
15 NICMOS dark current, shading profile, and read noise monitoring
program
The
purpose of this proposal is to monitor the dark current, read noise,
and
shading profile for all three NICMOS detectors throughout the
duration
of Cycle 15. This proposal is a slightly modified version of
proposal
10380 of cycle 13 and 9993 of cycle12 and is the same as Cycle
14.
that we cut down some exposure time to make the observation fit
within
24 orbits.
WFPC2
11037
Red
Filters Closeout
This
calibration program observes three very red stars {M, L, T dwarfs}
in
the five reddest broad and medium filters {F785LP, F791W, F814W,
F850LP,
and F1042M} on WF3 in order to allow cross-calibration to ACS,
and
in future WFC3. The far-red QE curves will also be tested. Similar
observations
on PC1 were made in WFPC2/CAL 10078 and 10366.
WFPC2
11024
WFPC2
CYCLE 15 INTERNAL MONITOR
This
calibration proposal is the Cycle 15 routine internal monitor for
WFPC2,
to be run weekly to monitor the health of the cameras. A variety
of
internal exposures are obtained in order to provide a monitor of the
integrity
of the CCD camera electronics in both bays {both gain 7 and
gain
15 -- to test stability of gains and bias levels}, a test for
quantum
efficiency in the CCDs, and a monitor for possible buildup of
contaminants
on the CCD windows. These also provide raw data for
generating
annual super-bias reference files for the calibration
pipeline.
NIC1
10889
The
Nature of the Halos and Thick Disks of Spiral Galaxies
We
propose to resolve the extra-planar stellar populations of the thick
disks
and halos of seven nearby, massive, edge-on galaxies using ACS,
NICMOS,
and WFPC2 in parallel. These observations will provide accurate
star
counts and color-magnitude diagrams 1.5 magnitudes below the tip of
the
Red Giant Branch sampled along the two principal axes and one
intermediate
axis of each galaxy. We will measure the metallicity
distribution
functions and stellar density profiles from star counts
down
to very low average surface brightnesses, equivalent to ~32 V-mag
per
square arcsec. These observations will provide the definitive HST
study
of extra-planar stellar populations of spiral galaxies. Our
targets
cover a range in galaxy mass, luminosity, and morphology and as
function
of these galaxy properties we will provide: - The first
systematic
study of the radial and isophotal shapes of the diffuse
stellar
halos of spiral galaxies - The most detailed comparative study
to
date of thick disk morphologies and stellar populations - A
comprehensive
analysis of halo and thick disk metallicity distributions
as
a function of galaxy type and position within the galaxy. - A
sensitive
search for tidal streams - The first opportunity to directly
relate
globular cluster systems to their field stellar population We
will
use these fossil records of the galaxy assembly process preserved
in
the old stellar populations to test halo and thick disk formation
models
within the hierarchical galaxy formation scheme. We will test
LambdaCDM
predictions on sub-galactic scales, where it is difficult to
test
using CMB and galaxy redshift surveys, and where it faces its most
serious
difficulties.
WFPC2
10832
Solving
the microlensing puzzle: An HST high-resolution imaging approach
We
propose to use the HST Advanced Camera for Surveys High Resolution
Channel
to obtain high resolution imaging data for 10 bona-fide LMC
microlensing
events seen in the original MACHO survey. The purpose of
this
survey will be to assess whether or not the lens and source stars
have
separated enough to be resolved since the original microlensing
event
took place - about a decade has passed since the original MACHO
survey
and the HST WFPC2 follow-up observations of the microlensing
events.
If the components of the lensing event are resolved, we will
determine
the apparent magnitude and color of both the lens and the
source
stars. These data, in combination with Spitzer/IRAC data and
Magellan
near-IR JHK data, will be used to ascertain the basic
properties
of the lens stars. With the majority of the microlensing
events
in the original MACHO survey observed at the highest spatial
resolution
currently possible, we will be able to draw important
conclusions
as to what fraction of these events have lenses which belong
to
some population of dwarf stars in the disk and what fraction must be
due
to lenses in the halo or beyond. These data will greatly increase
our
understanding of the structure of the Galaxy by characterizing the
stellar
population responsible for the gravitational microlensing.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
11052
- GSAcq (1,2,2) failed to RGA Hold during LOS
At acquisition of signal, 313/16:59:49, the GSAcq (1,2,2)
scheduled from
313/16:49:59 - 16:57:28 had failed to RGA Hold due to a stop flag
indication on FGS-1. No other 486 ESB messages were noted. Pre-acq
OBAD
data is unavailable due to LOS. Post-acquisition OBAD MAP at
313/16:57:28 had an RSS value of 19.98 arcseconds
At acquisition of signal, 313/18:54:59, the REAcq (1,2,2)
scheduled from
313/18:22:15 - 18:29:44 had failed to RGA Hold due to a stop flag
indication on FGS-1. No other 486 ESB messages were noted. Pre-acq
OBAD
data is unavailable due to LOS. Post-acquisition OBAD MAP at
313/16:57:28 had an RSS value of 13.12 arcseconds
11057
- REacq(1,2,2) failed to RGA Hold (Gyro Control)
REacq(1,2,2) scheduled at 316/02:30:31 - 02:38:36 failed to RGA
Hold due
to a Search Radius Limit Exceeded Error on FGS-2. One 486 ESB
"a05" (FGS
Coarse Track failed-Search Radius Limit Exceeded) was received at
316/02:34:51. Pre-acquisition OBADs had (RSS) values of 709.42 and
47.83
arcseconds. Post-acq OBAD/MAP had (RSS) value of 42.32 arcseconds.
Prior
guide star acquisition was successful.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
34
33
FGS
REacq
25
23
OBAD
with Maneuver
116
116
SIGNIFICANT
EVENTS:
Bi-Annual
BCC Failover Test
The
sixth biannual failover test to verify the backup control centers
ability
to support critical real-time operations was successfully
executed
on 11/9/07