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 # 4422
PERIOD
COVERED: UT August 08, 2007 (DOY 220)
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.
NIC1
10889
The
Nature of the Halos and Thick Disks of Spiral Galaxies
We
propose to resolve the extra-planar stellar populations of the thick
disks
and halos of seven nearby, massive, edge-on galaxies using ACS,
NICMOS,
and WFPC2 in parallel. These observations will provide accurate
star
counts and color-magnitude diagrams 1.5 magnitudes below the tip of
the
Red Giant Branch sampled along the two principal axes and one
intermediate
axis of each galaxy. We will measure the metallicity
distribution
functions and stellar density profiles from star counts
down
to very low average surface brightnesses, equivalent to ~32 V-mag
per
square arcsec. These observations will provide the definitive HST
study
of extra-planar stellar populations of spiral galaxies. Our
targets
cover a range in galaxy mass, luminosity, and morphology and as
function
of these galaxy properties we will provide: - The first
systematic
study of the radial and isophotal shapes of the diffuse
stellar
halos of spiral galaxies - The most detailed comparative study
to
date of thick disk morphologies and stellar populations - A
comprehensive
analysis of halo and thick disk metallicity distributions
as
a function of galaxy type and position within the galaxy. - A
sensitive
search for tidal streams - The first opportunity to directly
relate
globular cluster systems to their field stellar population We
will
use these fossil records of the galaxy assembly process preserved
in
the old stellar populations to test halo and thick disk formation
models
within the hierarchical galaxy formation scheme. We will test
LambdaCDM
predictions on sub-galactic scales, where it is difficult to
test
using CMB and galaxy redshift surveys, and where it faces its most
serious
difficulties.
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
11080
Exploring
the Scaling Laws of Star Formation
As
a variety of surveys of the local and distant Universe are
approaching
a full census of galaxy populations, our attention needs to
turn
towards understanding and quantifying the physical mechanisms that
trigger
and regulate the large-scale star formation rates {SFRs} in
galaxies.
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
11178
Probing
Solar System History with Orbits, Masses, and Colors of
Transneptunian
Binaries
The
recent discovery of numerous transneptunian binaries {TNBs} opens a
window
into dynamical conditions in the protoplanetary disk where they
formed
as well as the history of subsequent events which sculpted the
outer
Solar System and emplaced them onto their present day heliocentric
orbits.
To date, at least 47 TNBs have been discovered, but only about a
dozen
have had their mutual orbits and separate colors determined,
frustrating
their use to investigate numerous important scientific
questions.
The current shortage of data especially cripples scientific
investigations
requiring statistical comparisons among the ensemble
characteristics.
We propose to obtain sufficient astrometry and
photometry
of 23 TNBs to compute their mutual orbits and system masses
and
to determine separate primary and secondary colors, roughly tripling
the
sample for which this information is known, as well as extending it
to
include systems of two near-equal size bodies. To make the most
efficient
possible use of HST, we will use a
optimally
schedule our observations.
WFPC2
11203
A Search
for Circumstellar Disks and Planetary-Mass Companions around
Brown
Dwarfs in Taurus
During
a 1-orbit program in Cycle 14, we used WFPC2 to obtain the first
direct
image of a circumstellar disk around a brown dwarf. These data
have
provided fundamental new constraints on the formation process of
brown
dwarfs and the properties of their disks. To search for additional
direct
detections of disks around brown dwarfs and to search for
planetary-mass
companions to these objects, we propose a WFPC2 survey of
32
brown dwarfs in the Taurus star-forming region.
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
10
10
FGS
REacq
04
04
OBAD
with Maneuver 28
28
SIGNIFICANT
EVENTS: (None)