HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4532
PERIOD
COVERED: UT January 23, 2007 (DOY 023)
OBSERVATIONS
SCHEDULED
NIC1/NIC2
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
8795
NICMOS Post-SAA calibration - CR Persistence Part 6
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 DARKSs. 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 i
mages.
Each observation will need its own CRMAP, as different SAA
passages
leave different imprints on the NICMOS detectors.
WFPC2
11002
A
Census of LIRGs in Clusters of Galaxies in the First Half of the
Universe
from the IRAC Shallow Survey
The
incidence of LIRGs and ULIRGs is roughly two orders of magnitude
higher
in the field at redshift z > 1, and at these redshifts such
objects
dominate the global star formation activity. Mergers which fuel
such
activity might be expected to enhance the frequency of LIRGs in
dense
environments. We propose to use MIPS to obtain a census of LIRGs
in
z > 1 galaxy clusters from a well defined sample found in the IRAC
Shallow
Survey. Supporting IRAC and HST ACS data are also requested.
WFPC2
11038
Narrow
Band and Ramp Filter Closeout
These
observations are to improve calibration of narrow band and ramp
filters.
We also test for changes in the filter properties during
WFPC2's
14 years on-board HST.
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
06
06
FGS
REacq
06
06
OBAD
with Maneuver
24
24
SIGNIFICANT
EVENTS: (None)