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HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5205
PERIOD
COVERED: 8:00pm October 13 - 7:59pm October 14, 2010 (DOY
287/00:00z-287/23:59z)
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:
18941-0
- Clear GENSLEW Slot-1 for COS proposal 11639@287/0404z
COMPLETED
OPS NOTES: (None)
Scheduled Successful
FGS
GSAcq
8
8
FGS
REAcq
8
8
OBAD
with Maneuver 7 7
SIGNIFICANT
EVENTS: (None)
OBSERVATIONS
SCHEDULED:
COS/NUV/ACS/WFC/FUV
11658
Probing
the Outer Regions of M31 with QSO Absorption Lines
We
propose HST-COS spectroscopy of 10 quasars behind M31. Absorption
lines
due to MgII, FeII, CIV, and a variety of other lines will be
searched
for and measured. Six quasars lie between 1 and 4.2 Holmberg
radii
near the major axis on the southwest side, where confusion with
Milky
Way gas is minimized. Two lie even farther out on the southwest
side
of the major axis. One lies within 1 Holmberg radius. Two of the 10
pass
through M31's high velocity clouds seen in a detailed 21 cm
emission
map. Exposure time estimates were based on SDSS magnitudes and
available
GALEX magnitudes. Thus, using the most well-studied external
spiral
galaxy in the sky, our observations will permit us to check,
better
than ever before, the standard picture that quasar metal-line
absorption
systems such as MgII and CIV arise in an extended gaseous
halo/disk
of a galaxy well beyond its observable optical radius. The
observations
will yield insights into the nature of the gas and its
connection
to the very extended stellar components of M31 that have
recently
been studied. Notably the observations have the potential of
extending
M31's rotation curve to very large galactocentric distances,
thereby
placing new constraints on M31's dark matter halo.
Finally,
we also request that the coordinated parallel orbits be
allocated
to this program so that we may image the resolved stellar
content
of M31's halo and outer disk.
S/C
11639
Catching
Accreting WDs Moving into Their Instability Strip(s)
Our
past HST studies of the temperatures of 9 accreting, pulsating white
dwarfs
in cataclysmic variables show that 3 are in the normal
instability
strip for single white dwarfs, but the other 6 are much
hotter
(15, 000-16, 500K). This dual strip has been proposed to be due
to
mass differences in the white dwarfs related to evolutionary history
and
driven by the ionization of different elements in their respective
driving
regions. In 2007, GW Lib (the brightest and best studied of the
6
hot accreting pulsators) and V455 And (the brightest and best studied
of
the 3 cool accreting pulsators) underwent rare large amplitude dwarf
nova
outbursts (known to heat the white dwarf) and their pulsations
disappeared.
We propose COS observations to: a) take advantage of the
unprecedented
opportunity to view the change in pulsation modes due to
cooling
of the white dwarf envelope and b) determine the masses of the
white
dwarfs to test the dual strip theory. In addition, a nova that had
its
outburst 22 yrs ago has begun non-radial pulsations as it returns to
quiescence.
We will use COS to determine its temperature in relation to
the
instability strip for the pulsating white dwarfs in dwarf novae.
STIS/CCD
11845
CCD
Dark Monitor Part 2
Monitor
the darks for the STIS CCD.
STIS/CCD
11847
CCD
Bias Monitor-Part 2
Monitor
the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,
and
1x1 at gain = 4, to build up high-S/N superbiases and track the
evolution
of hot columns.
WFC3/IR
11696
Infrared
Survey of Star Formation Across Cosmic Time
We
propose to use the unique power of WFC3 slitless spectroscopy to
measure
the evolution of cosmic star formation from the end of the
reionization
epoch at z>6 to the close of the galaxy-building era at
z~0.3.Pure
parallel observations with the grisms have proven to be
efficient
for identifying line emission from galaxies across a broad
range
of redshifts. The G102 grism on WFC3 was designed to extend this
capability
to search for Ly-alpha emission from the first galaxies.
Using
up to 250 orbits of pure parallel WFC3 spectroscopy, we will
observe
about 40 deep (4-5 orbit) fields with the combination of G102
and
G141, and about 20 shallow (2-3 orbit) fields with G141 alone.
Our
primary science goals at the highest redshifts are: (1) Detect Lya
in
~100 galaxies with z>5.6 and measure the evolution of the Lya
luminosity
function, independent of of cosmic variance; 2) Determine the
connection
between emission line selected and continuum-break selected
galaxies
at these high redshifts, and 3) Search for the proposed
signature
of neutral hydrogen absorption at re-ionization. At
intermediate
redshifts we will (4) Detect more than 1000 galaxies in
Halpha
at 0.5<z<1.8 to measure the evolution of the extinction-corrected
star
formation density across the peak epoch of star formation. This is
over
an order-of-magnitude improvement in the current statistics, from
the
NICMOS Parallel grism survey. (5) Trace ``cosmic downsizing" from
0.5<z<2.2;
and (6) Estimate the evolution in reddening and metallicty in
star-forming
galaxies and measure the evolution of the Seyfert
population.
For hundreds of spectra we will be able to measure one or
even
two line pair ratios -- in particular, the Balmer decrement and
[OII]/[OIII]
are sensitive to gas reddening and metallicity. As a bonus,
the
G102 grism offers the possibility of detecting Lya emission at
z=7-8.8.
To
identify single-line Lya emitters, we will exploit the wide
0.8--1.9um
wavelength coverage of the combined G102+G141 spectra. All
[OII]
and [OIII] interlopers detected in G102 will be reliably separated
from
true LAEs by the detection of at least one strong line in the G141
spectrum,
without the need for any ancillary data. We waive all
proprietary
rights to our data and will make high-level data products
available
through the ST/ECF.
WFC3/UV
12008
Primordial
formation of Close Binaries in Globular Clusters with Low
Density
Cores
The
primordial binary population is a key input parameter for any
realistic
model of dense star cluster dynamics. However, the number of
primordial
binaries and its direct implications for the formation rate
of
close binaries remain poorly understood. Theoretical calculations
show
that cataclysmic variables can be formed directly from primordial
binaries
in or near the core of low core density globular clusters. We
propose
to use Chandra/HST to study low density core globular clusters
systematically
and to test the prediction that low-luminosity X-ray
sources
can be formed from primordial binaries in the cluster core. This
project
will complement our successful Chandra/HST program to study the
dynamical
formation of X-ray sources in high core density globular
clusters.
WFC3/UV
12019
After
the Fall: Fading AGN in Post-starburst Galaxies
We
propose joint Chandra and HST observations of an extraordinary sample
of
12 massive post-starburst galaxies at z=0.4-0.8 that are in the
short-lived
evolution phase a few 100 Myr after the peak of
merger-driven
star formation and AGN activity. We will use the data to
measure
X-ray luminosities, black hole masses, and accretion rates; and
with
the accurate "clocks" provided by post-starburst stellar
populations,
we will directly test theoretical models that predict a
power-law
decay in the AGN light curve. We will also test whether star
formation
and black hole accretion shut down in lock-step, quantify
whether
the black holes transition to radiatively inefficient accretion
states,
and constrain the observational signatures of black hole
mergers.
WFC3/UV
12215
Searching
for the Missing Low-Mass Companions of Massive Stars
Recent
results on binary companions of massive O stars appear to
indicate
that the distribution of secondary masses is truncated at low
masses.
It thus mimics the distribution of companions of G dwarfs and
also
the Initial Mass Function (IMF), except that it is shifted upward
by
a factor of 20 in mass. These results, if correct, provide a
distribution
of mass ratios that hints at a strong constraint on the
star-formation
process. However, this intriguing result is derived from
a
complex simulation of data which suffer from observational
incompleteness
at the low-mass end.
We
propose a snapshot survey to test this result in a very direct way.
HST
WFC3 images of a sample of the nearest Cepheids (which were formerly
B
stars of ~5 Msun) will search for low-mass companions down to M
dwarfs.
We will confirm any companions as young stars, and thus true
physical
companions, through follow-up Chandra X-ray images. Our survey
will
show clearly whether the companion mass distribution is truncated
at
low masses, but at a mass much higher than that of the IMF or G
dwarfs.
WFC3/UV
12245
Orbital
Evolution and Stability of the Inner Uranian Moons
Nine
densely-packed inner moons of Uranus show signs of chaos and
orbital
instability over a variety of time scales. Many moons show
measureable
orbital changes within a decade or less. Long-term
integrations
predict that some moons could collide in less than one
million
years. One faint ring embedded in the system may, in fact, be
the
debris left behind from an earlier such collision. Meanwhile, the
nearby
moon Mab falls well outside the influence of the others but
nevertheless
shows rapid, as yet unexplained, changes in its orbit. It
is
embedded within a dust ring that also shows surprising variability. A
highly
optimized series of observations with WFC3 over the next three
cycles
will address some of the fundamental open questions about this
dynamically
active system: Do the orbits truly show evidence of chaos?
If
so, over what time scales? What can we say about the masses of the
moons
involved? What is the nature of the variations in Mab's orbit? Is
Mab's
motion predictable or random? Astrometry will enable us to derive
the
orbital elements of these moons with 10-km precision. This will be
sufficient
to study the year-by-year changes and, combined with other
data
from 2003-2007, the decadal evolution of the orbits. The pairing of
precise
astrometry with numerical integrations will enable us to derive
new
dynamical constraints on the masses of these moons. Mass is the
fundamental
unknown quantity currently limiting our ability to reproduce
the
interactions within this system. This program will also capitalize
upon
our best opportunity for nearly 40 years to study the unexplained
variations
in Uranus's faint outer rings.
WFC3/UVIS
11905
WFC3
UVIS CCD Daily Monitor
The
behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame,
four-amp bias and dark frames. A smaller set of 2Kx4K
subarray
biases are acquired at less frequent intervals throughout the
cycle
to support subarray science observations. The internals from this
proposal,
along with those from the anneal procedure (Proposal 11909),
will
be used to generate the necessary superbias and superdark reference
files
for the calibration pipeline (CDBS).
WFC3/UVIS/IR
11644
A
Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into
the
Formation of the Outer Solar System
The
eight planets overwhelmingly dominate the solar system by mass, but
their
small numbers, coupled with their stochastic pasts, make it
impossible
to construct a unique formation history from the dynamical or
compositional
characteristics of them alone. In contrast, the huge
numbers
of small bodies scattered throughout and even beyond the
planets,
while insignificant by mass, provide an almost unlimited number
of
probes of the statistical conditions, history, and interactions in
the
solar system. To date, attempts to understand the formation and
evolution
of the Kuiper Belt have largely been dynamical simulations
where
a hypothesized starting condition is evolved under the
gravitational
influence of the early giant planets and an attempt is
made
to reproduce the current observed populations. With little
compositional
information known for the real Kuiper Belt, the test
particles
in the simulation are free to have any formation location and
history
as long as they end at the correct point. Allowing compositional
information
to guide and constrain the formation, thermal, and
collisional
histories of these objects would add an entire new dimension
to
our understanding of the evolution of the outer solar system. While
ground
based compositional studies have hit their flux limits already
with
only a few objects sampled, we propose to exploit the new
capabilities
of WFC3 to perform the first ever large-scale
dynamical-compositional
study of Kuiper Belt Objects (KBOs) and their
progeny
to study the chemical, dynamical, and collisional history of the
region
of the giant planets. The sensitivity of the WFC3 observations
will
allow us to go up to two magnitudes deeper than our ground based
studies,
allowing us the capability of optimally selecting a target list
for
a large survey rather than simply taking the few objects that can be
measured,
as we have had to do to date. We have carefully constructed a
sample
of 120 objects which provides both overall breadth, for a general
understanding
of these objects, plus a large enough number of objects in
the
individual dynamical subclass to allow detailed comparison between
and
within these groups. These objects will likely define the core
Kuiper
Belt compositional sample for years to come. While we have many
specific
results anticipated to come from this survey, as with any
project
where the field is rich, our current knowledge level is low, and
a
new instrument suddenly appears which can exploit vastly larger
segments
of the population, the potential for discovery -- both
anticipated
and not -- is extraordinary.
WFC3/UVIS/IR
11909
UVIS
Hot Pixel Anneal
The
on-orbit radiation environment of WFC3 will continually generate new
hot
pixels. This proposal performs the procedure required for repairing
those
hot pixels in the UVIS CCDs. During an anneal, the two-stage
thermo-electric
cooler (TEC) is turned off and the four-stage TEC is
used
as a heater to bring the UVIS CCDs up to ~20 deg. C. As a result of
the
CCD warmup, a majority of the hot pixels will be fixed; previous
instruments
such as WFPC2 and ACS have seen repair rates of about 80%.
Internal
UVIS exposures are taken before and after each anneal, to allow
an
assessment of the procedure's effectiveness in WFC3, provide a check
of
bias, global dark current, and hot pixel levels, as well as support
hysteresis
(bowtie) monitoring and CDBS reference file generation. One
IR
dark is taken after each anneal, to provide a check of the IR
detector.