Daily Report #4480

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.