Daily Report # 4357

Notice: For the foreseeable future, the daily reports may contain apparent
discrepancies between some proposal descriptions and the listed instrument
usage. This is due to the conversion of previously approved ACS WFC or HRC
observations into WFPC2, or NICMOS observations subsequent to the loss of
ACS CCD science capability in late January.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4357

PERIOD COVERED: UT May 07, 2007 (DOY 127)

OBSERVATIONS SCHEDULED

WFPC2 10800

Kuiper Belt Binaries: Probes of Early Solar System Evolution

Binaries in the Kuiper Belt are a scientific windfall: in them we have
relatively fragile test particles which can be used as tracers of the early
dynamical evolution of the outer Solar System. We propose to continue a
Snapshot program using the ACS/HRC that has a demonstrated discovery
potential an order of magnitude higher than the HST observations that have
already discovered the majority of known transneptunian binaries. With this
continuation we seek to reach the original goals of this project: to
accumulate a sufficiently large sample in each of the distinct populations
collected in the Kuiper Belt to be able to measure, with statistical
significance, how the fraction of binaries varies as a function of their
particular dynamical paths into the Kuiper Belt. Today's Kuiper Belt bears
the imprints of the final stages of giant-planet building and migration;
binaries may offer some of the best preserved evidence of that long-ago era.

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.

WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for
supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS},
have found hundreds of SNe, many of them in quite nearby galaxies {cz 4000
km/s}. Most of the objects were discovered before maximum brightness, and
have follow-up photometry and spectroscopy; they include some of the
best-studied SNe to date. We propose to conduct a snapshot imaging survey of
the sites of some of these nearby objects, to obtain late-time photometry
that {through the shape of the light and color curves} will help reveal the
origin of their lingering energy. The images will also provide
high-resolution information on the local environments of SNe that are far
superior to what we can procure from the ground. For example, we will obtain
color-color and color-magnitude diagrams of stars in these SN sites, to
determine the SN progenitor masses and constraints on the reddening.
Recovery of the SNe in the new HST images will also allow us to actually
pinpoint their progenitor stars in cases where pre- explosion images exist
in the HST archive. This proposal is an extension of our successful Cycle 13
snapshot survey with ACS. It is complementary to our Cycle 15 archival
proposal, which is a continuation of our long-standing program to use
existing HST images to glean information about SN environments.

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/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 DARKSs. 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.

NIC1/NIC3 10924

Constraints on the Assembly and Dynamical Masses of z~2 Galaxies

We propose deep NICMOS/NIC2 F160W imaging of seven star-forming galaxies at
z~2. These galaxies comprise an entirely unique sample, with not only
redshifts measured from optical and near-IR spectra, but also SINFONI/VLT
near-IR integral field spectroscopic measurements providing kinematic maps
of H-alpha emission out to radii of =10 kpc. We aim to determine the
dynamical masses and evolutionary states of these systems, as part of the
larger goal of understanding how mass is assembled in distant galaxies. In
order to interpret our novel H-alpha integral field maps in terms of mass,
we require detailed knowledge of the structural parameters of our target
objects at rest-frame optical wavelengths and on ~1 kpc scales. We want to
establish if the mass is distributed in a disk, bulge, or merging sub-units,
and if we can detect tidal features associated with a merger. F160W imaging
with NICMOS/NIC2 provides the perfect combination of sensitivity and
resolution to address these questions, and arrive at the fundamental
quantity: the dynamical mass.

NIC2 10849

Imaging Scattered Light from Debris Disks Discovered by the Spitzer Space
Telescope around 21 Sun-like Stars

We propose to use the high-contrast capability of the NICMOS coronagraph to
image a sample of newly discovered circumstellar disks associated with
Sun-like stars. These systems were identified by their strong thermal
infrared {IR} emission with the Spitzer Space Telescope as part of the
Spitzer Legacy Science program titled "The Formation and Evolution of
Planetary Systems" {FEPS, P.I.: M.Meyer}. Modeling of the thermal excess
emission from the spectral energy distributions alone cannot distinguish
between narrowly confined high-opacity disks and broadly distributed,
low-opacity disks. By resolving light scattered by the circumstellar
material, our proposed NICMOS observations can break this degeneracy, thus
revealing the conditions under which planet formation processes are occuring
or have occured. For three of our IR-excess stars that have known
radial-velocity planets, resolved imaging of the circumstellar debris disks
may further offer an unprecedented view of planet-disk interactions in an
extrasolar planetary system. Even non-detections of the light scattered by
the circumstellar material will place strong constraints on the disk
geometries, ruling out disk models with high optical depth. Unlike previous
disk imaging programs, our program contains a well-defined sample of ~1
solar mass stars covering a range of ages from 3 Myr to 3 Gyr, thus allowing
us to study the evolution of disks from primordial to debris for the first
time. The results from our program will greatly improve our understanding of
the architecture of debris disks around Sun-like stars, and will create a
morphological context for the existence of our own solar system. This
proposal is for a continuation of an approved Cycle 14 program {GO/10527,
P.I.: D. Hines}.

WFPC2 11002

A Census of LIRGs in Clusters of Galaxies in the First Half of the Universe
from the IRAC Shallow Survey

The incidence of LIRGs and ULIRGs is roughly two orders of magnitude higher
in the field at redshift z 1, and at these redshifts such objects dominate
the global star formation activity. Mergers which fuel such activity might
be expected to enhance the frequency of LIRGs in dense environments. We
propose to use MIPS to obtain a census of LIRGs in z 1 galaxy clusters
from a well defined sample found in the IRAC Shallow Survey. Supporting IRAC
and HST ACS data are also requested.

WFPC2 11023

WFPC2 CYCLE 15 Standard Darks - part 1

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.

WFPC2 11075

The 2006 outburst of RS Oph - Second epoch HST observations of evolving
structures

We propose to use second epoch HST DD time to perform high resolution
optical imaging of the 2006 outburst of the Recurrent Nova RS Ophiuchi,
which underwent its last recorded outburst in 1985. In this system, high
velocity ejecta from a WD near the Chandrasekhar mass impact the companion
red giant wind, setting up shock systems analogous to those in SNR. Our
first epoch observations in July 2006 {day 155} revealed for the first time
what appear to be the sub-arcsecond optical counterparts of the "jets" we
have observed in the radio. A striking similarity to the double rings of SN
1987A is however evident. In addition, previously unseen structures ~1
arcsec to the East and South are apparent. In addition to determining the
true source geometry and disentagling the contributions different regions of
the source make to unresolved spectra, the specific aims of our second epoch
observations are to determine {i} the expansion rate of the inner extended
features, allowing comparison with simple shock models and helping to
constrain the distance to RS Oph; {ii} whether the eastern "arc" and
southern "blob" show any motion, helping to determine whether they are the
result of previous outbursts, and {iii} the rate of change of emission in
the observed lines, for direct comparison with shock models, and also to
compare with the overall changes in line fluxes seen in infrared, optical
and uv spectroscopy. Our work on RS Oph has far wider-ranging importance
which includes furthering our understanding of the outbursts of novae, the
structure of red giant winds, jet ejection and collimation in astrophysical
sources, the progenitors of Type Ia supernovae and the evolution of
supernova remnants. Continued HST observations complement our
multi-frequency observing campaign, in particular our unrivalled coverage of
this event with VLBI.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST:

18072-1 - PCS KF OOT Support
18069-3 - MSS/CSS/Gyro2 KF Initialization Convergence Testing for SMS 127

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL

FGS GSacq 07 07
FGS REacq 07 07
OBAD with Maneuver 27 27

SIGNIFICANT EVENTS:

Evaluation of Universal Kalman Filter performance continued. Details follow.

The KF was halted at 127/18:15 (OR 18069-3). The filter was restarted at
127/18:18 with the CSS disabled, the Gyro2 input enabled, during orbit day,
during a vehicle slew and during an M2G guiding interval and during a slow
changing B-field. All UKF parameters showed nominal operation. The test was
an MSS/Gyro2 Initialization test case during a vehicle slew with a slow
changing B-field (M_G2_IVS, Test #35).

The KF was reconfigured and restarted at 127/19:14 with the CSS and both
gyro inputs disabled to leave the filter in an MSS only configuration. This
configuration is to help provide a earlier baseline set of data for PCS
analysis and it will remain the default configuration outside of other KF
convergence testing for the remainder of the week.