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 # 4468
PERIOD
COVERED: UT October 15, 2007 (DOY 288)
OBSERVATIONS
SCHEDULED
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.
NIC3
11107
Imaging
of Local Lyman Break Galaxy Analogs: New Clues to Galaxy
Formation
in the Early Universe
We have
used the ultraviolet all-sky imaging survey currently being
conducted
by the Galaxy Evolution Explorer {GALEX} to identify for the
first
time a rare population of low- redshift starbursts with properties
remarkably
similar to high-redshift Lyman Break Galaxies {LBGs}. These
"compact
UV luminous galaxies" {UVLGs} resemble LBGs in terms of size,
SFR,
surface brightness, mass, metallicity, kinematics, dust, and color.
The
UVLG sample offers the unique opportunity of investigating some very
important
properties of LBGs that have remained virtually inaccessible
at
high redshift: their morphology and the mechanism that drives their
star
formation. Therefore, in Cycle 15 we have imaged 7 UVLGs using ACS
in
order to 1} characterize their morphology and look for signs of
interactions
and mergers, and 2} probe their star formation histories
over
a variety of timescales. The images show a striking trend of
small-scale
mergers turning large amounts of gas into vigorous
starbursts
{a process referred to as dissipational or "wet" merging}.
Here,
we propose to complete our sample of 31 LBG analogs using the
ACS/SBC
F150LP {FUV} and WFPC2 F606W {R} filters in order to create a
statistical
sample to study the mechanism that triggers star formation
in
UVLGs and its implications for the nature of LBGs. Specifically, we
will
1} study the trend between galaxy merging and SFR in UVLGs, 2}
artificially
redshift the FUV images to z=1-4 and compare morphologies
with
those in similarly sized samples of LBGs at the same rest-frame
wavelengths
in e.g. GOODS, UDF, and COSMOS, 3} determine the presence
and
morphology of significant stellar mass in "pre-burst" stars, and 4}
study
their immediate environment. Together with our Spitzer
{IRAC+MIPS},
GALEX, SDSS and radio data, the HST observations will form
a
unique union of data that may for the first time shed light on how the
earliest
major episodes of star formation in high redshift galaxies came
about.
This proposal was adapted from an ACS HRC+WFC proposal to meet
the
new Cycle 16 observing constraints, and can be carried out using the
ACS/SBC
and WFPC2 without compromising our original science goals.
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
11141
White
dwarfs in the open star cluster NGC 188
White
dwarf cooling sequences represent the only ways in which we can
determine
ages of Galactic components such as the disk and the halo, and
they
are an independent check on main sequence ages of globular star
clusters.
These age measurements rely heavily on theoretical cooling
models,
many of which disagree by as much as a few gigayears for the
coolest
white dwarfs. Further, observations of the white dwarf sequence
in
the super metal- rich open cluster NGC 6791 have found a white dwarf
age
several gigayears younger than the accepted cluster age determined
by
main-sequence fitting. The white dwarf sequence of the
solar-metallicity,
7-Gyr old open cluster NGC 188 can provide some
much-needed
insight into these uncertainties, but previous HST
observations
were too shallow to detect the oldest, faintest white
dwarfs
in the cluster. We propose deep imaging of two fields at the
center
of the cluster with the following goals: {1} To detect the end of
the
white dwarf cooling sequence, providing a much-needed empirical data
point
for cool white dwarf evolutionary models, {2} to compare the white
dwarf
luminosity function of NGC 188 with that of NGC 6791 to determine
if
the odd white dwarf sequence in the latter cluster is due to the
cluster's
high metallicity or due to a shortcoming in theoretical
models,
and {3} to determine via photometry the masses of white dwarfs
formed
by solar-mass stars, a quantity not yet empirically measured.
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.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
11024
- GSAcq(2,1,2) failed to RGA Hold (Gyro Control)
Upon acquisition of signal at 288/09:56:46, the GSAcq(2,1,2)
scheduled
at 288/09:26:40 - 09:34:44 had failed to RGA Hold due to
(QF2STOPF) stop
flag indication on FGS-2. Pre-acquisition OBAD1 (RSS) attitude
correction error not available due to LOS. OBAD2 had (RSS) value
of 4.86
arcseconds
REACQ(2,1,2) at 11:00:00 was successful.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
06
05
FGS
REacq
09
09
OBAD
with Maneuver 30
30
SIGNIFICANT
EVENTS: (None)