Email distribution of the
HST Daily Report will cease on ~10/8/10. The Daily Report can now be
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HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5190
PERIOD
COVERED: 5am September 26 - 5am September 27, 2010 (DOY 270/00:00z-270/23:59z)
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: (None)
COMPLETED
OPS NOTES: (None)
Scheduled
Successful
FGS
GSAcq
13
13
FGS
REAcq
05
05
OBAD
with Maneuver 11
11
SIGNIFICANT
EVENTS: (None)
OBSERVATIONS
SCHEDULED:
ACS/WFC
11996
CCD
Daily Monitor (Part 3)
This
program comprises basic tests for measuring the read noise and dark
current
of the ACS WFC and for tracking the growth of hot pixels. The
recorded
frames are used to create bias and dark reference images for
science
data reduction and calibration. This program will be executed
four
days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To
facilitate
scheduling, this program is split into three proposals. This
proposal
covers 308 orbits (19.25 weeks) from 21 June 2010 to 1 November
2010.
ACS/WFC
12209
A
Strong Lensing Measurement of the Evolution of Mass Structure in Giant
Elliptical
Galaxies
The
structure and evolution of giant elliptical galaxies provide key
quantitative
tests for the theory of hierarchical galaxy formation in a
cold
dark matter dominated universe. Strong gravitational lensing
provides
the only direct means for the measurement of individual
elliptical
galaxy masses beyond the local universe, but there are
currently
no large and homogeneous samples of strong lens galaxies at
significant
cosmological look-back time. Hence, an accurate and
unambiguous
measurement of the evolution of the mass-density structure
of
elliptical galaxies has until now been impossible. Using
spectroscopic
data from the recently initiated Baryon Oscillation
Spectroscopic
Survey (BOSS) of luminous elliptical galaxies at redshifts
from
approximately 0.4 to 0.7, we have identified a large sample of
high-probability
strong gravitational lens candidates at significant
cosmological
look-back time, based on the detection of emission-line
features
from more distant galaxies along the same lines of sight as the
target
ellipticals. We propose to observe 45 of these systems with the
ACS-WFC
in order to confirm the incidence of lensing and to measure the
masses
of the lens galaxies. We will complement these lensing mass
measurements
with stellar velocity dispersions from ground-based
follow-up
spectroscopy. In combination with similar data from the Sloan
Lens
ACS (SLACS) Survey at lower redshifts, we will directly measure the
cosmic
evolution of the ratio between lensing mass and dynamical mass,
to
reveal the structural explanation for the observed size evolution of
elliptical
galaxies (at high mass). We will also measure the evolution
of
the logarithmic mass-density profile of massive ellipticals, which is
sensitive
to the details of the merging histories through which they are
assembled.
Finally, we will use our lensing mass-to-light measurements
to
translate the BOSS galaxy luminosity function into a mass function,
and
determine its evolution in combination with data from the original
Sloan
Digital Sky Survey.
ACS/WFC
12210
SLACS
for the Masses: Extending Strong Lensing to Lower Masses and
Smaller
Radii
Strong
gravitational lensing provides the most accurate possible
measurement
of mass in the central regions of early-type galaxies
(ETGs).
We propose to continue the highly productive Sloan Lens ACS
(SLACS)
Survey for strong gravitational lens galaxies by observing a
substantial
fraction of 135 new ETG gravitational-lens candidates with
HST-ACS
WFC F814W Snapshot imaging. The proposed target sample has been
selected
from the seventh and final data release of the Sloan Digital
Sky
Survey, and is designed to complement the distribution of previously
confirmed
SLACS lenses in lens-galaxy mass and in the ratio of Einstein
radius
to optical half-light radius. The observations we propose will
lead
to a combined SLACS sample covering nearly two decades in mass,
with
dense mapping of enclosed mass as a function of radius out to the
half-light
radius and beyond. With this longer mass baseline, we will
extend
our lensing and dynamical analysis of the mass structure and
scaling
relations of ETGs to galaxies of significantly lower mass, and
directly
test for a transition in structural and dark-matter content
trends
at intermediate galaxy mass. The broader mass coverage will also
enable
us to make a direct connection to the structure of well-studied
nearby
ETGs as deduced from dynamical modeling of their line-of-sight
velocity
distribution fields. Finally, the combined sample will allow a
more
conclusive test of the current SLACS result that the intrinsic
scatter
in ETG mass-density structure is not significantly correlated
with
any other galaxy observables. The final SLACS sample at the
conclusion
of this program will comprise approximately 130 lenses with
known
foreground and background redshifts, and is likely to be the
largest
confirmed sample of strong-lens galaxies for many years to come.
ACS/WFC3
11882
CCD
Hot Pixel Annealing
This
program continues the monthly anneal that has taken place every
four
weeks for the last three cycles. We now obtain WFC biases and darks
before
and after the anneal in the same sequence as is done for the ACS
daily
monitor (now done 4 times per week). So the anneal observation
supplements
the monitor observation sets during the appropriate week.
Extended
Pixel Edge Response (EPER) and First Pixel Response (FPR) data
will
be obtained over a range of signal levels for the Wide Field
Channel
(WFC). This program emulates the ACS pre-flight ground
calibration
and post-launch SMOV testing (program 8948), so that results
from
each epoch can be directly compared. The High Resolution Channel
(HRC)
visits have been removed since it could not be repaired during
SM4.
This
program also assesses the read noise, bias structure, and amplifier
cross-talk
of ACS/WFC using the GAIN=1.4 A/D conversion setting. This
investigation
serves as a precursor to a more comprehensive study of WFC
performance
using GAIN=1.4.
COS/FUV
11895
FUV
Detector Dark Monitor
Monitor
the FUV detector dark rate by taking long science exposures
without
illuminating the detector. The detector dark rate and spatial
distribution
of counts will be compared to pre-launch and SMOV data in
order
to verify the nominal operation of the detector. Variations of
count
rate as a function of orbital position will be analyzed to find
dependence
of dark rate on proximity to the SAA. Dependence of dark rate
as
function of time will also be tracked.
COS/FUV
11897
FUV
Spectroscopic Sensitivity Monitoring
The
purpose of this proposal is to monitor sensitivity in each FUV
grating
mode to detect any changes due to contamination or other causes.
COS/FUV
11997
FUV
Internal/External Wavelength Scale Monitor
This
program monitors the offsets between the wavelength scale set by
the
internal wavecal versus that defined by absorption lines in external
targets.
This is accomplished by observing two external targets in the
SMC:
SK191 with G130M and G160M and Cl* NGC 330 ROB B37 with G140L
(SK191
is too bright to be observed with G140L). The cenwaves observed
in
this program are a subset of the ones used during Cycle 17. Observing
all
cenwaves would require a considerably larger number of orbits.
Constraints
on scheduling of each target are placed so that each target
is
observed once every ~2-3 months. Observing the two targets every
month
would also require a considerably larger number of orbits.
COS/NUV
11894
NUV
Detector Dark Monitor
The
purpose of this proposal is to measure the NUV detector dark rate by
taking
long science exposures with no light on the detector. The
detector
dark rate and spatial distribution of counts will be compared
to
pre-launch and SMOV data in order to verify the nominal operation of
the
detector. Variations of count rate as a function of orbital position
will
be analyzed to find dependence of dark rate on proximity to the
SAA.
Dependence of dark rate as function of time will also be tracked.
COS/NUV
11896
NUV
Spectroscopic Sensitivity Monitoring
The
purpose of this proposal is to monitor sensitivity of each NUV
grating
mode to detect any changes due to contamination or other causes.
COS/NUV
12041
COS-GTO:
Io Atmosphere/STIS
We
will use six HST orbits with COS to observe the disk-integrated
longitudinal
distribution of Io's atmosphere, and ten HST orbits with
STIS
to provide complementary disk-resolved information at key
locations.
We wil use the COS G225M grating to observe four SO2
absorption
bands, which can be used to determine SO2 atmospheric
density.
Disk-integrated 19 micron observations of the atmosphere
indicate
that the anti-Jupiter hemisphere of Io has an atmospheric
density
roughly ten times greater than the Jupiter-facing side (Spencer
et
al. 2005), and mm-wave observations suggest a similar pattern.
However
the infrared and mm-wave observations cannot easily separate
atmospheric
density from atmospheric temperature, so these results are
model-dependent.
Sparse 2100 2300 disk-resolved observations
(McGrath
et al. 2000, Jessup et al. 2004) tell a consistent story, but
do
not cover enough of Io's surface to provide full confirmation of the
long-wavelength
result. We will therefore observe Io's disk-integrated
atmospheric
density at six longitudes, roughly 30, 90, 150, 210, 270,
and
330 W, to confirm the 19 micron results and improve our ability to
model
the 19-micron data. With STIS, we plan disk-resolved 2000-3200
spectroscopy
of Io's SO2 atmosphere. Our observations will target
low-latitude
regions away from active plumes (in contrast to our Cycle
10
observations (Jessup et al. 2004) which targeted the Prometheus
plume),
to look for the effect of plumes on the atmosphere. We will also
look
at the variation of low-latitude atmospheric abundance with terrain
type,
to look for explanations for the large longitudinal variations in
atmospheric
pressure to be studied with COS. Finally, we will look at a
variety
of regions at two different times of day to determine the extent
of
diurnal variations in the atmosphere, which are expected if the
atmosphere
is dominantly supported by frost sublimation.
COS/NUV/FUV/WFC3/UV
12248
How
Dwarf Galaxies Got That Way: Mapping Multiphase Gaseous Halos and
Galactic
Winds Below L*
One
of the most vexing problems in galaxy formation concerns how gas
accretion
and feedback influence the evolution of galaxies. In high mass
galaxies,
numerical simulations predict the initial fuel is accreted
through
'cold' streams, after which AGN suppress star formation to leave
galaxies
red and gas-poor. In the shallow potential wells that host
dwarf
galaxies, gas accretion can be very efficient, and "superwinds"
driven
either by hot gas expelled by SNe or momentum imparted by SNe and
hot-star
radiation are regarded as the likely source(s) of feedback.
However,
major doubts persist about the physics of gas accretion, and
particularly
about SN-driven feedback, including their scalings with
halo
mass and their influence on the evolution of the galaxies. While
"superwinds"
are visible in X-rays near the point of their departure,
they
generally drop below detectable surface-brightness limits at ~ 10
kpc.
Cold clumps in winds can be detected as blue-shifted absorption
against
the galaxy's own starlight, but the radial extent of these winds
are
difficult to constrain, leaving their energy, momentum, and ultimate
fate
uncertain. Wind prescriptions in hydrodynamical simulations are
uncertain
and at present are constrained only by indirect observations,
e.g.
by their influence on the stellar masses of galaxies and IGM
metallicity.
All these doubts lead to one conclusion: we do not
understand
gas accretion and feedback because we generally do not
observe
the infall and winds directly, in the extended gaseous halos of
galaxies,
when it is happening. To do this effectively, we must harness
the
power of absorption-line spectroscopy to measure the density,
temperature,
metallicity, and kinematics of small quantities of diffuse
gas
in galaxy halos. The most important physical diagnostics lie in the
FUV,
so this is uniquely a problem for HST and COS. We propose new COS
G130M
and G160M observations of 41 QSOs that probe the gaseous halos of
44
SDSS dwarf galaxies well inside their virial radii. Using sensitive
absorption-line
measurements of the multiphase gas diagnostics Lya,
CII/IV,
Si II/III/IV, and other species, supplemented by optical data
from
SDSS and Keck, we will map the halos of galaxies with L = 0.02 -
0.3
L*, stellar masses M* = 10^(8-10) Msun, over impact parameter from
15
- 150 kpc. These observations will directly constrain the content and
kinematics
of accreting and outflowing material, provide a concrete
target
for simulations to hit, and statistically test proposed galactic
superwind
models. These observations will also inform the study of
galaxies
at high z, where the shallow halo potentials that host dwarf
galaxies
today were the norm. These observations are low-risk and
routine
for COS, easily schedulable, and promise a major advance in our
understanding
of how dwarf galaxies came to be.
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/S/C
11929
IR
Dark Current Monitor
Analyses
of ground test data showed that dark current signals are more
reliably
removed from science data using darks taken with the same
exposure
sequences as the science data, than with a single dark current
image
scaled by desired exposure time. Therefore, dark current images
must
be collected using all sample sequences that will be used in
science
observations. These observations will be used to monitor changes
in
the dark current of the WFC3-IR channel on a day-to-day basis, and to
build
calibration dark current ramps for each of the sample sequences to
be
used by Gos in Cycle 17. For each sample sequence/array size
combination,
a median ramp will be created and delivered to the
calibration
database system (CDBS).
WFC3/U
12015
Rapid
Follow-Up Observations of Tidal Disruption Events Discovered by
Pan-STARRS1
We
propose for rapid follow-up Chandra TOO ACIS-S observations and
HST/COS
NUV imaging and FUV low-resolution spectroscopy of 5 flares from
the
tidal disruption of stars by supermassive black holes discovered in
the
Pan-STARRS1 Medium Deep Survey. With TOO observations obtained
within
a month of the peak of the flare, and 5 months later, we aim to
1)
constrain the flare's broadband SED and bolometric luminosity, 2)
follow
the decay of the flare and look for spectral evolution, and 3)
place
strong limits on the presence of a persistent AGN nucleus. Tidal
disruption
events provide a cosmic laboratory to study the physics of
accretion
onto black holes, and are a unique probe of the mass of black
holes
in the nuclei of distant galaxies.
WFC3/UV
11635
In
Search of SNIb/Ic Wolf-Rayet Progenitors and Comparison with Red
Supergiants
(SNII Progenitors) in the Giant ScI Spiral M101
We
propose to test two of the clearest predictions of the theory of
evolution
of massive-star evolution: 1) The formation of Wolf-Rayet
stars
depends strongly on these stars' metallicity (Z), with relatively
fewer
WR stars forming at lower Z, and 2) Wolf-Rayet stars die as Type
Ib
or Ic supernovae. To carry out these tests we propose a deep,
narrowband
imaging survey of the massive star populations in the ScI
spiral
galaxy M101. Just as important, we will test the hypothesis that
Superclusters
like 30 Doradus are always richly populated with WR stars,
and
by implication that these complexes are responsible for the spectral
signatures
of starburst galaxies.
Our
previous HST survey of the HII regions in the ScIII galaxy NGC 2403
suggested
that the distribution of WR stars and RSG is a sensitive
diagnostic
of the recent star-forming history of these large complexes:
young
cores of O and WR stars are surrounded by older halos containing
RSG.
Theory predicts that this must change with metallicity; relatively
fewer
WR stars form at lower Z. A key goal of our proposal is to
directly
test this paradigm in a single galaxy, M101 being the ideal
target.
The abundance gradient across M101 (a factor of 20) suggests
that
relatively many more WR will be found in the inner parts of this
galaxy
than in the outer "suburbs". Second, we note that WR stars are
predicted
to end their lives as core-collapse or pair-instability
supernovae.
The WR population in M101 may be abundant enough for one to
erupt
as a Type Ib or Ic supernova within a generation. The clear a
priori
identification of a WR progenitor would be a major legacy of HST.
Third,
we will also determine if "superclusters", heavily populated by
WR
stars, are common in M101. It is widely claimed that such
Superclusters
produce the integrated spectral signatures of Starburst
galaxies.
We will be able to directly measure the numbers and
emission-line
luminosities of thousands of Wolf Rayet stars located in
hundreds
of M101 Superclusters, and correlate those numbers against the
Supercluster
sizes and luminosities. It is likely (but far from certain)
that
Supercluster sizes and emission-line luminosities are driven by
their
Wolf-Rayet star content. Our sample will be the largest and
best-ever
Supercluster/Wolf Rayet sample, an excellent local proxy for
characterizing
starburst galaxies' Superclusters.
WFC3/UV
12237
Orbits,
Masses, Densities, and Colors of Two Transneptunian Binaries
Binaries
are the key to learning many crucial bulk properties of
transneptunian
objects (TNOs) including their masses. Perhaps the most
interesting
mass-dependent property of a TNO is its bulk density, which
provides
unique information about its bulk composition and interior
structure.
Densities have so far only been measured for a handful of
binary
TNO systems. This proposal seeks to determine orbits and thus
masses
of two more binary TNOs, both of which are also to be observed at
thermal
infrared wavelengths by the Herschel spacecraft. Combining the
masses
from Hubble with the sizes from Herschel will enable us to
compute
their densities. We will also obtain multi-wavelength
photometric
colors of the individual components of each binary system.
It
is imperative to link colors to the physical properties measurable in
binary
systems in order to use the remnant planetesimals in today's
Kuiper
belt to learn more about the early history of our own solar
system,
and more generally about how planetesimals form in nebular disks
and
subsequently evolve.
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).