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Daily Report #5190



 
 
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Old September 28th 10, 04:03 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5190


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).
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