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      # 4480

PERIOD COVERED: UT October 31, 2007 (DOY 304)

OBSERVATIONS SCHEDULED

ACS/SBC 10840

The FUV fluxes of Tauri stars in the Taurus molecular cloud

Present and forthcoming ground-based and space surveys of the T Tauri
stars in the Taurus molecular cloud will provide information from high
energy stellar and accretion radiation to low energy solid state and
molecular emission from the disk, making those stars perfect
laboratories to carry out self-consistent studies of disk physics and
evolution. We propose to complete this wealth of information by
obtaining ACS/FUV spectra for a significant sample of Taurus T Tauri
stars, covering a range of accretion properties and dust evolutionary
stages. FUV fluxes carry ~ 10 - 100 more energy than X-rays into these
disks and are thus crucial gas heating agents and key to disk dispersal
by photoevaporation. These observations are a pre-requisite to interpret
observations with Spitzer, SOFIA, Herschel, and ALMA, and will become
one of the important legacies of HST to the star formation community.

WFPC2 10905

The Dynamic State of the Dwarf Galaxy Rich Canes Venatici I Region

With accurate distances, the nearest groups of galaxies can be resolved
in 3 dimensions and the radial component of the motions of galaxies due
to local density perturbations can be distinguished from cosmological
expansion components. Currently, with the ACS, galaxy distances within 8
Mpc can be measured effectively and efficiently by detecting the tip of
the red giant branch {TRGB}. Of four principal groups at high galactic
latitude in this domain, the Canes Venatici I Group {a} is the least
studied, {b} is the most populated, though overwhelmingly by dwarf
galaxies, and {c} is likely the least dynamically evolved. It is
speculated that galaxies in low mass groups may fail to retain baryons
as effectively as those in high mass groups, resulting in significantly
higher mass-to-light ratios. The CVn I Group is suspected to lie in the
mass regime where the speculated astrophysical processes that affect
baryon retention are becoming important.

NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

This takes a series of Darks in parallel to other instruments.

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.

NIC2 11197

Sweeping Away the Dust: Reliable Dark Energy with an Infrared Hubble
Diagram

We propose building a high-z Hubble Diagram using type Ia supernovae
observed in the infrared rest-frame J-band. The infrared has a number of
exceptional properties. The effect of dust extinction is minimal,
reducing a major systematic that may be biasing dark energy
measurements. Also, recent work indicates that type Ia supernovae are
true standard candles in the infrared meaning that our Hubble diagram
will be resistant to possible evolution in the Phillip's relation over
cosmic time. High signal-to-noise measurements of 16 type Ia events at
z~0.4 will be compared with an independent optical Hubble diagram from
the ESSENCE project to test for a shift in the derived dark energy
equation of state due to a systematic bias. In Cycle 15 we obtained
NICMOS photometry of 8 ESSENCE supernovae and are awaiting template
observations to place them on the IR Hubble diagram. Here we request
another 8 supernovae be studied in the final season of the ESSENCE
search. Because of the bright sky background, H-band photometry of z~0.4
supernovae is not feasible from the ground. Only the superb image
quality and dark infrared sky seen by HST makes this test possible. This
experiment may also lead to a better, more reliable way of mapping the
expansion history of the universe with the Joint Dark Energy Mission.

S/C 11163

Accreting Pulsating White Dwarfs in Cataclysmic Variables

Recent ground-based observations have increased the number of known
pulsating white dwarfs in close binaries with active mass transfer
{cataclysmic variables} from 5 to 11 systems. Our past Cycles 8 and 11
STIS observations of the first 2 known, followed by our Cycle 13 SBC
observations of the next 3 discovered, revealed the clear presence of
the white dwarf and increased amplitude of the pulsations in the UV
compared to the optical. The temperatures derived from the UV spectra
show 4 systems are much hotter than non- interacting pulsating white
dwarfs. A larger sample is needed to sort out the nature of the
instability strip in accreting pulsators i.e. whether effects of
composition and rotation due to accretion result in a well-defined
instability strip as a function of Teff.

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 11167

A Unique High Resolution Window to Two Strongly Lensed Lyman Break
Galaxies

On rare occasions, the otherwise very faint Lyman Break Galaxies {LBGs}
are magnified by gravitational lensing to provide exceptional targets
for detailed spectroscopic and imaging studies. We propose HST WFPC2 and
NICMOS imaging of two strongly lensed Lyman Break Galaxies {LBGs} that
were recently discovered by members of our team. These two LBGs -- the
"8 O'Clock Arc" and the "SDSS J1206+5142 Arc" -- are currently the
brightest known LBGs, roughly 3 times brighter than the former
record-holder, MS1512-cB58 {a.k.a. "cB58"}. The z=2.73 "8 O'Clock Arc"
extends ~10 arcsec in length and is magnified by a factor of 12. The
z=2.00 "SDSS J1206+5142 Arc" also extends ~10 arcsec in length and is
magnified by a factor of 30. Due to their brightness and magnification,
these two strongly lensed LBGs offer an unprecedented opportunity for
the very detailed investigation of two individual galaxies at high
redshift. We are currently pursuing a vigorous ground-based campaign to
obtain multi-wavelength {UV, optical, NIR, radio} observations of these
two LBGs, but our campaign currently lacks a means of obtaining
high-resolution optical/NIR imaging -- a lack that currently only HST
can address. Our prime objective for this proposal is to obtain high
resolution HST images of these two systems with two-orbit WFPC2 images
in the BVI bands and two-orbit NICMOS/NIC2 images in the J and H bands.
These data will allow us to construct detailed lensing models, probe the
mass and light profiles of the lenses and their environments, and
constrain the star formation histories and rest-frame UV/optical
spectral energy distributions of the LBGs.

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.

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 within 15 Mpc, each SN stands an excellent chance of detection with
HST and Spitzer and of resolving potential light echoes.

WFPC2 11418

Investigating the Spectacular Outburst of Comet 17P/Holmes

Comet 17P/Holmes is currently undergoing a spectacular eruption in
activity, with its brightness increasing by ~14 mag over a 24 hour
period. The comet is shedding huge amounts of dust, presumably
associated with a major splitting event at the nucleus. The high spatial
resolution and high sensitivity of Hubble has proven to be invaluable
during previous observations of several fragmenting comets, and the 2007
apparition of 17P/Holmes represents another excellent opportunity to
investigate this important cometary phenomenon. We request 3 orbits of
WFPC2 observations to measure the size and V-R color of the principal
nucleus, perform a deep search for large fragments released during the
outburst, monitor the temporal development of the event, and search for
a satellite whose collision with the principal nucleus may have
triggered the current outburst, as was suggested for the similar
outburst observed in 1892.

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:
18151-0 - Clear ACS SBC Event Flag #2 for OBS #11163
18152-1 - Modify CSS 3/4 Scale Factors for UKF
18054-0 - Preview KF Sun Vector Data via Telemetry Diags

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL
FGS GSacq               06                 06                   
FGS REacq               09                 09               
OBAD with Maneuver 30                30        

SIGNIFICANT EVENTS:
The execution of Ops Request 18152-1, Modify CSS 3/4 Scale Factors for
UKF, completed successfully at 2007/304 18:57.