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 # 4415
PERIOD COVERED: UT July 30, 2007 (DOY 211)
OBSERVATIONS SCHEDULED
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.
WFPC2 11081
RR Lyrae stars in M31 Globular
Clusters: How did the M31 Spiral Galaxy
Form?
The pulsation properties of the RR Lyrae
stars in the globular clusters
of the Andromeda galaxy {M31} have
the potential to provide essential
insight on the first epoch of the
galaxy formation and to trace the
merging episodes that led to the
assembly of M31. Their mean periods
along with the cluster metallicities can provide an independent estimate
of the M31 cluster ages and, in
turn, of the time scale of the M31 halo
formation, by comparison with their Milky
Way counterparts. We will
observe RR Lyrae
stars in 6 appropriately selected globular clusters of
M31 using WFPC2 to derive periods, light curves, and
physical parameters
of these eyewitnesses of the first
epochs of the M31 formation.
ACS/SBC 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.
WFPC2 11292
The Ring Plane Crossings of Uranus in 2007
The rings of Uranus turn edge-on to Earth in May and
August 2007. In
between, we will have a rare
opportunity to see the unlit face of the
rings. With the nine optically thick
rings essentially invisible, we will
observe features and phenomena that are
normally lost in their glare. We
will use this opportunity to search
thoroughly for the embedded
"shepherd" moons long
believed to confine the edges of the rings,
setting a mass limit roughly 10 times
smaller than that of the smallest
shepherd currently known, Cordelia. We will measure the vertical
thicknesses of the rings and study the
faint dust belts only known to
exist from a single Voyager image. We
will also study the colors of the
newly-discovered faint, outer rings; recent evidence
suggests that one
ring is red and the other blue,
implying that each ring is dominated by
a different set of physical
processes. We will employ near-edge-on
photometry from 2006 and 2007 to derive
the particle filling factor
within the rings, to observe how ring
epsilon responds to the "traffic
jam" as particles pass through
its narrowest point, and to test the
latest models for preserving
eccentricities and apse alignment within
the rings. Moreover, this data set
will allow us to continue monitoring
the motions of the inner moons,
which have been found to show possibly
chaotic orbital variations; by nearly
doubling the time span of the
existing Hubble astrometry, the details
of the variations will become
much clearer.
WFPC2/NIC3 11188
First Resolved Imaging of Escaping Lyman Continuum
The emission from star-forming galaxies appears to be
responsible for
reionization of the universe at z>6.
However, the models that attempt to
describe the detailed impact of high- redshift galaxies on the
surrounding inter-galactic medium {IGM} are
strongly dependent upon
several uncertain parameters. Perhaps
the most uncertain is the fraction
of HI-ionizing photons produced by
young stars which escape into the
IGM. Most attempts to measure this
"escape fraction" {f_esc} have
produced null results. Recently, a small
subset of z~3 Lyman Break
Galaxies {LBGs} has been found
exhibiting large escape fractions. It
remains unclear however, what
differentiates them from other LBGs.
Several models attempt to explain how such a large
fraction of ionizing
continuum can escape through the HI and
dust in the ISM {eg. "chimneys"
created by SNe
winds, globular cluster formation, etc.}, each producing
unique signatures which can be
observed with resolved imaging of the
escaping Lyman continuum. We propose a
deep, high resolution WFPC2 image
of the ionizing continuum {F336W}
and the rest-frame 1500 Angstrom
continuum {F606W} of five of the six
known LBGs with large escape
fractions. These LBGs
all fit within a single WFPC2 pointing, yielding
high observing efficiency.
Additionally, they all have z~3.1 or higher,
the optimal redshift
range for probing the Lyman Continuum region with
available WFPC2 filters. These factors
make our proposed sample
especially suitable for follow- up. With
these data we will discern the
mechanisms responsible for producing large
escape fractions, and
therefore gain insight into the process
of reionization.
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 04 04
FGS REacq 11 11
OBAD with Maneuver
30 30
SIGNIFICANT EVENTS: (None)
-Lynn
____________________________________________________________
Lynn F. Bassford
Hubble Space Telescope
CHAMP Mission Operations
Manager
CHAMP Flight Operations Team Manager
Lockheed Martin Mission Services (LMMS)
NASA GSFC PH#: 301-286-2876
"The Hubble Space Telescope is the
astronomical observatory and key to unlocking the most cosmic mysteries of the
past, present and future." - 7/26/6