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 # 4447
PERIOD
COVERED: UT September 13, 2007 (DOY 256)
OBSERVATIONS
SCHEDULED
ACS/SBC
WFPC2 11175
UV
Imaging to Determine the Location of Residual Star Formation in
Galaxies
Recently Arrived on the Red Sequence
We
have identified a sample of low-redshift {z = 0.04 - 0.10} galaxies
that
are candidates for recent arrival on the red sequence. They have
red
optical colors indicative of old stellar populations, but blue
UV-optical
colors that could indicate the presence of a small quantity
of
continuing or very recent star formation. However, their spectra lack
the
emission lines that characterize star-forming galaxies. We propose
to
use ACS/SBC to obtain high- resolution imaging of the UV flux in
these
galaxies, in order to determine the spatial distribution of the
last
episode of star formation. WFPC2 imaging will provide B, V, and I
photometry
to measure the main stellar light distribution of the galaxy
for
comparison with the UV imaging, as well as to measure color
gradients
and the distribution of interstellar dust. This detailed
morphological
information will allow us to investigate the hypothesis
that
these galaxies have recently stopped forming stars and to compare
the
observed distribution of the last star formation with predictions
for
several different mechanisms that may quench star formation in
galaxies.
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.
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
wavelenghts
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.
NIC3
11335
NICMOS
Defocus parameter test
This
proposal tests the new NICMOS non-nominal focus positions, which
are
implemented in the front-end systems and are specified in the Phase
II
using the CAMERA-FOCUS=DEFOCUS Optional Parameter. The targets from
Proposals
9832 and 11063 are used in this Proposal. The GO Proposal 9832
is
an example of how GOs may use the new non-nominal focus
implementation
for detector 3. Proposal 11063 is the NICMOS focus
monitor,
which will be used to verify the non-nominal focus for all 3
detectors.
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
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
11218
Snapshot
Survey for Planetary Nebulae in Globular Clusters of the Local
Group
Planetary
nebulae {PNe} in globular clusters {GCs} raise a number of
interesting
issues related to stellar and galactic evolution. The number
of
PNe known in Milky Way GCs, 4, is surprisingly low if one assumes
that
all stars pass through a PN stage. However, it is likely that the
remnants
of stars now evolving in Galactic GCs leave the AGB so slowly
that
any ejected nebula dissipates long before the star becomes hot
enough
to ionize it. Thus there should not be ANY PNe in Milky Way
GCs--but
there are four! It has been suggested that these PNe are the
result
of mergers of binary stars within GCs, i.e., that they are
descendants
of blue stragglers. The frequency of occurrence of PNe in
external
galaxies poses more questions, because it shows a range of
almost
an order of magnitude. I propose a Snapshot survey aimed at
discovering
PNe in the GC systems of Local Group galaxies more distant
than
the Magellanic Clouds. These clusters, some of which may be much
younger
than their counterparts in the Milky Way, might contain many
more
PNe than those of our own galaxy. I will use the standard technique
of
emission-line and continuum imaging, which easily discloses PNe.
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: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
08
08
FGS
REacq
07
07
OBAD
with Maneuver
30
30
SIGNIFICANT
EVENTS: (None)