Daily Report #4443

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****** # 4443

PERIOD COVERED: UT September 07,08,09, 2007 (DOY 250, 251, 252)

OBSERVATIONS SCHEDULED

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 0.15z0.3. 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 {z1} 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 11229

SEEDS: The Search for Evolution of Emission from Dust in Supernovae
with HST and Spitzer

The role that massive stars play in the dust content of the Universe
is extremely uncertain. It has long been hypothesized that dust can
condense within the ejecta of supernovae {SNe}, however there is a
frustrating discrepancy between the amounts of dust found in the early
Universe, or predicted by nucleation theory, and inferred from SN
observations. Our SEEDS collaboration has been carefully revisiting
the observational case for dust formation by core-collapse SNe, in
order to quantify their role as dust contributors in the early
Universe. As dust condenses in expanding SN ejecta, it will increase
in optical depth, producing three simultaneously observable phenomena:
{1} increasing optical extinction; {2} infrared {IR} excesses; and {3}
asymmetric blue-shifted emission lines. Our SEEDS collaboration
recently reported all three phenomena occurring in SN2003gd,
demonstrating the success of our observing strategy, and permitting us
to derive a dust mass of up to 0.02 solar masses created in the SN. To
advance our understanding of the origin and evolution of the
interstellar dust in galaxies, we propose to use HST's WFPC2 and
NICMOS instruments plus Spitzer's photometric instruments to monitor
ten recent core- collapse SNe for dust formation and, as a bonus,
detect light echoes that can affect the dust mass estimates. These
space-borne observations will be supplemented by ground- based
spectroscopic monitoring of their optical emission line profiles.
These observations would continue our 2-year HST and Spitzer
monitoring of this phenomena in order to address two key questions: Do
all SNe produce dust? and How much dust do they produce? As all the SN
are witin 15 Mpc, each SN stands an excellent chance of detection with
HST and Spitzer and of resolving potential light echoes.

FGS 11213

Distances to Eclipsing M Dwarf Binaries

We propose HST FGS observations to measure accurate distances of 5
nearby M dwarf eclipsing binary systems, from which model-independent
luminosities can be calculated. These objects have either poor or no
existing parallax measurements. FGS parallax determinations for these
systems, with their existing dynamic masses determined to better than
0.5%, would serve as model-independent anchor points for the low-mass
end of the mass-luminosity diagram.

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.

WFPC2 11201

Systemic and Internal motions of the Magellanic Clouds: Third Epoch
Images

In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields
in the Magellanic Clouds centered on background quasars. We used these
data to determine the proper motions of the LMC and SMC to better than
5% and 15% respectively. These are by far the best determinations of
the proper motions of these two galaxies. The results have a number of
unexpected implications for the Milky Way-LMC-SMC system. The implied
three-dimensional velocities are larger than previously believed, and
are not much less than the escape velocity in a standard 10^12 solar
mass Milky Way dark halo. Orbit calculations suggest the Clouds may
not be bound to the Milky Way or may just be on their first passage,
both of which would be unexpected in view of traditional
interpretations of the Magellanic Stream. Alternatively, the Milky Way
dark halo may be a factor of two more massive than previously
believed, which would be surprising in view of other observational
constraints. Also, the relative velocity between the LMC and SMC is
larger than expected, leaving open the possibility that the Clouds may
not be bound to each other. To further verify and refine our results
we now request an epoch of WFPC2/PC data for the fields centered on 40
quasars that have at least one epoch of ACS imaging. We request
execution in snapshot mode, as in our previous programs, to ensure the
most efficient use of HST resources. A third epoch of data of these
fields will provide crucial information to verify that there are no
residual systematic effects in our previous measurements. More
importantly, it will increase the time baseline from 2 to 5 yrs and
will increase the number of fields with at least two epochs of data.
This will reduce our uncertainties correspondingly, so that we can
better address whether the Clouds are indeed bound to each other and
to the Milky Way. It will also allow us to constrain the internal
motions of various populations within the Clouds, and will allow us to
determine a distance to the LMC using rotational parallax.

WFPC2 11122

Expanding PNe: Distances and Hydro Models

We propose to obtain repeat narrowband images of a sample of eighteen
planetary nebulae {PNe} which have HST/WFPC2 archival data spanning
time baselines of a decade. All of these targets have previous high
signal-to-noise WFPC2/PC observations and are sufficiently nearby to
have readily detectable expansion signatures after a few years. Our
main scientific objectives are {a} to determine precise distances to
these PNe based on their angular expansions, {b} to test detailed and
highly successful hydrodynamic models that predict nebular
morphologies and expansions for subsamples of round/elliptical and
axisymmetric PNe, and {c} to monitor the proper motions of nebular
microstructures in an effort to learn more about their physical nature
and formation mechanisms. The proposed observations will result in
high-precision distances to a healthy subsample of PNe, and from this
their expansion ages, luminosities, CSPN properties, and masses of
their ionized cores. With good distances and our hydro models, we will
be able to determine fundamental parameters {such as nebular and
central star masses, luminosity, age}. The same images allow us to
monitor the changing overall ionization state and to search for the
surprisingly non-homologous growth patterns to bright elliptical PNe
of the same sort seen by Balick & Hajian {2004} in NGC 6543.
Non-uniform growth is a sure sign of active pressure imbalances within
the nebula that require careful hydro models to understand.

WFPC2 11115

Photometric Imaging of Asteroid 2 Pallas

We propose to conduct the first HST imaging of Asteroid 2 Pallas with
WFPC2-PC over 4 HST orbits. We will image the asteroid in five
filters: F336w, F439w, F555w, F675w and F814w. We will utilize these
observations to drastically improve the knowledge of Pallas' shape,
spin pole position and surface properties, including roughness and
albedo, parameters that are poorly determined by previous study. These
observations will result in high signal-to-noise, high resolution
surface maps from the visible to the UV. A satellite search will also
be conducted for objects within the stability field of up to 21st
magnitude, or about 900m in diameter. It is demonstrated in our
proposal that significant scientific opportunity exists in Cycle 16
because Pallas is at both a low-phase, 3.9 degree opposition and near
its closest approach to Earth, conditions that do not occur
simultaneously in the next twenty years. This window represents the
best chance to answer long standing, fundamental questions about
Pallas, the main asteroid belt, and the formation of the solar
system.

WFPC2 11084

Probing the Least Luminous Galaxies in the Local Universe

We propose to obtain deep color-magnitude data of eight new Local
Group galaxies which we recently discovered: Andromeda XI, Andromeda
XII, and Andromeda XIII {satellites of M31}; Canes Venatici I, Canes
Venatici II, Hercules, and Leo IV {satellites of the Milky Way}; and
Leo T, a new "free-floating" Local Group dwarf spheroidal with
evidence for recent star formation and associated H I gas. These
represent the least luminous galaxies known at *any* redshift, and are
the only accessible laboratories for studying this extreme regime of
galaxy formation. With deep WFPC-2 F606W and F814W pointings at their
centers, we will determine whether these objects contain single or
multiple age stellar populations, as well as whether these objects
display a range of metallicities.

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 11034

WFPC2 Closeout Photometric Characterization

The standard star GRW+70D5829 is observed in filter and chip
combinations that were not included in photometric calibration
programs from 2005, 2006, and 2007. These observations are needed to
complete a library of recent standard star observations taken in all
filter and chip combinations before WFPC2 is decommissioned in SM4.
{Linear Ramp and Polarizer filters are covered in a separate
proposal.} These observations, along with other recent standard star
observations, will be used to study long-term throughput.

WFPC2 11022

WFPC2 Cycle 15 Decontaminations and Associated Observations

This proposal is for the WFPC2 decons. Also included are instrument
monitors tied to decons: photometric stability check, focus monitor,
pre- and post-decon internals {bias, intflats, kspots, & darks}, UV
throughput check, VISFLAT sweep, and internal UV flat check.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and
highly non-uniform archive, making comprehensive comparative studies
among galaxies essentially impossible. We propose to secure HST's
lasting impact on the study of nearby galaxies by undertaking a
systematic, complete, and carefully crafted imaging survey of ALL
galaxies in the Local Universe outside the Local Group. The resulting
images will allow unprecedented measurements of: {1} the star
formation history {SFH} of a 100 Mpc^3 volume of the Universe with a
time resolution of Delta[log{t}]=0.25; {2} correlations between
spatially resolved SFHs and environment; {3} the structure and
properties of thick disks and stellar halos; and {4} the color
distributions, sizes, and specific frequencies of globular and disk
clusters as a function of galaxy mass and environment. To reach these
goals, we will use a combination of wide-field tiling and pointed deep
imaging to obtain uniform data on all 72 galaxies within a
volume-limited sample extending to ~3.5 Mpc, with an extension to the
M81 group. For each galaxy, the wide-field imaging will cover out to
~1.5 times the optical radius and will reach photometric depths of at
least 2 magnitudes below the tip of the red giant branch throughout
the limits of the survey volume. One additional deep pointing per
galaxy will reach SNR~10 for red clump stars, sufficient to recover
the ancient SFH from the color-magnitude diagram. This proposal will
produce photometric information for ~100 million stars {comparable to
the number in the SDSS survey} and uniform multi- color images of half
a square degree of sky. The resulting archive will establish the
fundamental optical database for nearby galaxies, in preparation for
the shift of high- resolution imaging to the near-infrared.

WFPC2 10818

Very Young Globular Clusters in M31 ?

We propose to use HST's unique high spatial resolution imaging
capabilities to conclusively confirm or refute the presence of alleged
very young globular clusters in M31. Such young globular clusters with
ages 3 Gyr are not present in our galaxy, and, if real, would lead
to a striking difference in the age distribution of the GCs between
M31 and the Milky Way. If the apparent presence of very young globular
clusters in M31 is confirmed through our proposed ACS imaging {now
WFPC2 imaging} with HST, this would suggest major differences in the
history of assembly of the two galaxies, with probable substantial
late accretion into M31 which did not occur in our own galaxy.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10988 - GSACQ(2,1,2) failed, Search Radius Limit Exceeded on FGS 2

GSACQ(2,1,2) at 251/11:44:35 failed at 11:50:07 with search radius
limit exceeded on FGS 2. OBADs prior to GSACQ had RSS errors of
1793.72 and 10.09 arcseconds, OBAD map after acquisition had error
17.96 arcseconds.

REACQ(2,1,2) at 13:16:32 also failed at 13:22:01

10897 - Unplanned HST communications outage

HST experienced an unplanned communication outage beginning at about
15:46 GMT on Friday, September 7. Communication was restored via LGAs
at ~17:53 GMT following a telemetry switch to A-format (4kps). All
spacecraft systems were verified nominal and communications were
re-configured back to HST high-gain antennas. There were no hardware
anomalies and normal science activities continued throughout the
period without loss of science data.

Analysis confirmed that the S/C communications equipment was left in
coherent mode following a planned 2-way tracking event. This permitted
capture of the HST MA transponder by a ground station overflight of
the USN station at South Point, Hawaii. Per the hardware's design,
detection of the ground signal by the HST transponder resulted in a
transition to GSTDN-mode baseband RF signal. The two subsequent TDRSS
passes were

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

********************** SCHEDULED***** SUCCESSFUL
FGS GSacq************** 18**************** 17
FGS REacq************** 25**************** 24
OBAD with Maneuver 88**************** 88

SIGNIFICANT EVENTS: (None)