Email
distribution of the HST Daily Report will cease on ~10/15/10. The
Daily
Report can now be found, and will continue to appear at:
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heading "HST Daily Report."
Reports
for the prior "Zulu Day," 00:00:00 to 23:59:59 Universal Time,
will
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From
the switchover date forward, Daily Reports will be issued 7 days a
week
instead of M-F only.
HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5199-#5202
PERIOD
COVERED: 8:00pm October 7 - 7:59pm October 11, 2010 (DOY 281/00:00z-284/23:59z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12459
- GSAcq(1,2,1) scheduled at 282/08:45:01z and REAcq(1,2,1)scheduled at
282/09:57:21z both resulted in fine lock backup (1,0,1).
Observations possibly affected: ACS 77-82 Proposal ID#11575
12460
- GSAcq(2,1,1) scheduled at 282/11:16:52z failed due to search radius limit
exceeded on FGS 1 and FGS 2.
Observations affected: ACS 83 Proposal#12210; WFC3 138 Proposal
ID#12380
12461
- REAcq(2,3,3) scheduled at 283/10:16:45 failed due to search radius
limit exceeded on FGS 2
Observations affected: ACS 114-117, WFC3 189-190 Proposal ID#12061
12462
- GSAcq(1,0,1) scheduled at 283/11:53:12z failed due to search radius limit
exceeded on FGS 1.
and REAcq(1,0,1) scheduled at 283/13:38:26z failed due to SRLEX on
FGS 1
Observations affected: WFC3 191-194 Proposal ID#12061; ACS 118-122
Proposal ID#12061
12463
- GSAcq(1,2,1) at 283/15:20:54z and REAcq(1,2,1) scheduled at 283/16:42:54z,
283/18:18:47z, and at 283/19:54:40z all failed due to search
radius
limit exceeded on FGS 2.
Observations affected: WFC3 196-214 Proposal ID#12181; WFC3 215
Proposal ID#12380
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
45
42
FGS
REAcq
22
17
OBAD
with Maneuver
35
35
SIGNIFICANT
EVENTS: (None)
OBSERVATIONS
SCHEDULED:
WFC3/IR
12380
Guard
Darks
The
goal of the Guard Dark program is to collect WFC3/IR dark current
data
prior to each visit in two of the Multi-Cycle Treasury (MCT)
programs
in Cycle 18. By scheduling a dark current observation between
the
last pre-MCT observation and the first MCT visit, we will be able to
measure
any residual persistent signal resulting from the former which
may
affect the latter.
WFC3/UV
12345
UVIS
Long Darks Test
Darks
during SMOV showed a systematically lower global dark rate as well
as
lower scatter when compared to the Cycle 17 darks. Those two sets of
exposures
differ in exposure time - 1800 sec during SMOV and 900 sec
during
Cycle 17. Hypothetically, the effect could be caused by
short-duration
stray light, say ~500-sec in duration. During the latter
part
of Cycle 17, operation of WFC3 was changed to additionally block
the
light path to the detector with the CSM. This program acquires a
small
number of darks at the longer SMOV exposure times (1800 sec) in
order
to check whether the effect repeats in the new operating mode.
WFC3/UV
12344
Cycle
18: UVIS Bowtie Monitor
Ground
testing revealed an intermittent hysteresis type effect in the
UVIS
detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially
found via an unexpected bowtie-shaped feature in flatfield
ratios,
subsequent lab tests on similar e2v devices have since shown
that
it is also present as simply an overall offset across the entire
CCD,
i.e., a QE offset without any discernable pattern. These lab tests
have
further revealed that overexposing the detector to count levels
several
times full well fills the traps and effectively neutralizes the
bowtie.
Each visit in this proposal acquires a set of three 3x3 binned
internal
flatfields: the first unsaturated image will be used to detect
any
bowtie, the second, highly-exposed image will neutralize the bowtie
if
it is present, and the final image will allow for verification that
the
bowtie is gone.
WFC3/IR
12307
A
public SNAPSHOT Survey of Gamma-ray Burst Host Galaxies
We
propose to conduct a public infrared survey of the host galaxies of
Swift
selected gamma-ray bursts (GRBs) at z<3. By obtaining deep,
diffraction
limited imaging in the IR we will complete detections for
the
host galaxies, and in concert with our extensive ground based
afterglow
and host programmes will compile a detailed catalog of the
properties
of high-z galaxies selected by GRBs. In particular these
observations
will enable us to study the colours, luminosities and
morphologies
of the galaxies. This in turn informs studies of the nature
of
the progenitors and the role of GRBs as probes of star formation
across
cosmic history. Ultimately it provides a product of legacy value
which
will greatly complement further studies with next generation
facilities
such as ALMA and JWST.
COS/NUV/FUV
12299
Spectroscopic
Signatures of Binary and Recoiling Black Holes
We
propose to obtain UV the spectra of the Ly-alpha and Mg II lines of
13
SDSS quasars whose H-beta lines are offset by 1000-4000 km/s from
their
systemic redshifts. Such lines have been suggested to originate in
recoiling
or close binary black holes. However these interpretations are
not
unique and UV spectroscopy, possible only with the HST, can
discriminate
between competing possibilities. Identifying such systems
is
extremely important in the context of scenarios for galaxy formation
and
evolution and in view of recent predictions from numerical
relativity.
Close binary black holes represent an apparently inevitable
stage
in the merger of two massive galaxies. The subsequent merger of
the
members of the binary is expected to produce a recoiling black hole
in
some fraction of cases. Thus, the census of such systems, their
environments,
and hosts can constrain some of the more uncertain
parameters
in evolutionary models. But before we can find them in any
numbers,
we need to evaluate the candidates known so far. This is the
goal
of our proposal.
STIS/CC
12291
STIS
coronagraphy of Spitzer-selected debris disks
Debris
disks trace the structure, dynamic, and formation of exoplanetary
systems.
In the cases of Fomalhaut and HR 8799 exoplanets have been
imaged
at the locations expected from the disk structures. Fifteen
percent
of main sequence stars possess dusty circumstellar debris disks
revealed
by far-infrared photometry. These disks are signposts of
planetary
systems: collisions among larger, unseen parent bodies
maintain
the observed dust population against losses to radiation
pressure
and Poynting-Robertson drag. Images of debris disks at optical,
infrared,
and millimeter wavelengths have shown central holes, rings,
radial
gaps, warps, and azimuthal asymmetries which indicate the
presence
of planetary mass perturbers. Only twenty have been spatially
resolved
at any wavelength, and at wavelengths <10 microns (where
subarcsec
resolution is available), only fifteen. Imaging of dozens of
other
debris disk targets has been attempted with various HST
cameras/coronagraphs
and adaptive optics, but without success. The key
property
which renders a debris disk observable in scattered light is
its
dust optical depth. The sixteen disks imaged so far all have an
infrared
luminosity >~ 0.01% that of the central star; no disks with
smaller
optical depths have been detected. Most nearby, main-sequence
stars
known to meet this requirement have already been observed, so
future
progress in debris disk imaging depends on discovering additional
stars
with large infrared excess. The Spitzer Space Telescope provided
the
best opportunity in 20 years to identify new examples of high
optical
depth debris disk systems. We have conducted detailed imaging
simulations
of debris disks newly identified by Spitzer since 2007,
including
size, surface brightness, and contrast estimates. From these
we
have identified ten targets whose disks should be detectable with the
STIS
coronagraph in roll-subtracted images. In terms of their
detectability
and resolvability to HST, these are the best remaining
targets
to emerge from the now-complete Spitzer photometric surveys of
nearby
main sequence stars. Our goals are to obtain the first resolved
images
of these disks at ~3 AU resolution, define the disk sizes and
orientations,
and uncover disk substructures indicative of planetary
perturbations.
WFC3/IR
12286
Hubble
Infrared Pure Parallel Imaging Extragalactic Survey (HIPPIES)
WFC3
has demonstrated its unprecedented power in probing the early
universe.
Here we propose to continue our pure parallel program with
this
instrument to search for LBGs at z~6--8. Our program, dubbed as the
Hubble
Infrared Pure Parallel Imaging Extragalactic Survey ("HIPPIES"),
will
carry on the HST pure parallel legacy in the new decade. We request
205
orbits in Cycle-18, which will spread over ~ 50 high Galactic
latitude
visits (|b|>20deg) that last for 3 orbits and longer, resulting
a
total survey area of ~230 square arcmin. Combining the WFC3 pure
parallel
observations in Cycle-17, HIPPIES will complement other
existing
and forthcoming WFC3 surveys, and will make unique
contributions
to the study in the new redshift frontier because of the
randomness
of the survey fields. To make full use of the parallel
opportunities,
HIPPIES will also take ACS parallels to study LBGs at
z~5--6.
Being a pure parallel program, HIPPIES will only make very
limited
demand on the scarce HST resources, but will have potentially
large
scientific returns. As in previous cycle, we waive all proprietary
data
rights, and will make the enhanced data products public in a timely
manner.
(1)
The WFC3 part of HIPPIES aims at the most luminous LBG population at
z~8
and z~7. As its survey fields are random and completely
uncorrelated,
the number counts of the bright LBGs from HIPPIES will be
least
affected by the "cosmic variance", and hence we will be able to
obtain
the best constraint on the bright-end of the LBG luminosity
function
at z~8 and 7. Comparing the result from HIPPIES to the
hydrodynamic
simulations will test the input physics and provide insight
into
the nature of the early galaxies. (2) The z~7--8 candidates from
HIPPIES,
most of which will be the brightest ones that any surveys would
be
able to find, will have the best chance to be spectroscopically
confirmed
at the current 8--10m telescopes. (3) The ACS part of HIPPIES
will
produce a significant number of candidate LBGs at z~5 and z~6 per
ACS
field. Combining with the existing, suitable ACS fields in the HST
archive,
we will be able to utilize the random nature of the survey to
quantify
the
cosmic variance and to measure the galaxy bias at z~5--6, and
therefore
the galaxy halo masses at these redshifts. (4) We will also
find
a large number of extremely red, old galaxies at intermediate
redshifts,
and the fine spatial resolution offered by the WFC3 will
enable
us constrain their formation history based on the study of their
morphology,
and hence shed light on their connection to the very early
galaxies
in the universe.
WFC3/IR
12283
WFC3
Infrared Spectroscopic Parallel Survey (WISP): A Survey of Star
Formation
Across Cosmic Time
We
will use the unique power of WFC3 slitless spectroscopy to measure
cosmic
star formation across its peak epoch. The broad, continuous,
spectral
coverage of the G102 and G141 grisms provides the best
currently
feasible measurement of the star formation rate continuously
from
0.5<z<2.5, over which ground-based searches are severely limited.
Our
Cycle 17 pure-parallel grism program has proven efficient for
identifying
line emission from galaxies across this large fraction of
cosmic
time. With less than two months of WFC3 observing completed, our
new
measurements have more than
doubled the sample of emission-line
galaxies
that we found over the entire NICMOS Parallel Grism program. We
propose
to extend this cost-effective WFC3 Survey by using 280 orbits of
pure
parallel grism spectroscopy in 50 deep (4-5 orbit) fields with both
G102
and G141, and 40 shallow (2-3 orbit) fields with G141 alone. This
will
complete a sample of 2000-3000 emission line galaxies in the
"redshift
desert" and search for serendipitous Lya emitters at z>5.5.
Our
primary science goals are: (1) Measure ratios of bright emission
lines
([OII], [OIII], Ha, and Hb) in a substantial fraction of these
galaxies,
thereby estimating dust and metallicity evolution in a sample
of
galaxies that is not biased by photometric selection. (2) Derive an
extinction-corrected
Ha luminosity function, with a 20 times larger
sample
than our previous NICMOS results. (3) Measure the
mass-metallicity
relation at crucial intermediate redshifts, with the
support
of our ongoing ground-based, follow-up, observing program (4)
Determine
the spectroscopic close pair fraction in this sample, in order
to
constrain hierarchal merging models (5) Uncover a new sample of
obscured
AGN at these redshifts and, (6) Use the Balmer break diagnostic
to
constrain the ages of continuum detected sources down to H = 25.
As
a bonus, these observations will be sensitive to Lya emission at
z>5.5,
taking advantage of continuous spectral coverage to observe large
volumes
for luminous galaxies at the highest redshifts. Over Cycles 17
and
18, we expect to detect 5-20 LAEs over redshifts spanning 5.5 < z <
7.5.
These observations will likely place the most stringent constraint
on
the numbers of z>6.5 Lya emitters until JWST. We are waiving all
proprietary
rights to our data and will make high-level data products
available
through the ST/ECF.
WFC3/IR
12251
The
First Characterization of a Super-Earth Atmosphere
Our
team recently discovered the first transiting super-Earth exoplanet
whose
atmosphere can be studied with HST. GJ1214b is a 2.7 Earth radius,
6.6
Earth mass exoplanet that transits a low-mass M dwarf located a mere
13
pc away. With only a mass and radius known, structural models show
that
GJ1214b may either have an extended H-rich envelope or consist of a
body
that is mostly water, surrounded by a thin, H-poor atmosphere. We
propose
to observe the planet in transit with WFC3 IR's G141 grism to
measure
its transmission spectrum between 1.1 and 1.7 microns. Our
primary
science goal is to determine the super-Earth's atmospheric scale
height,
thus distinguishing between its possible bulk compositions. The
summed
light curve will permit a search for transiting moons around
GJ1214b
the size of Ganymede. Among the presently known transiting
exoplanets,
GJ1214b is the smallest, coolest, most Earth-like planet
that
has a substantial atmosphere. Fortunately, the small radius of the
star
means studying GJ1214b's atmosphere requires no better precision
than
has already been demonstrated by HST observations of transiting hot
Jupiters.
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.
WFC3/UV/IR
12234
Differentiation
in the Kuiper belt: a Search for Silicates on Icy
Bodies.
We
currently have a large on-going program (Go Program 11644, 120
orbits)
to exploit the superb stability and photometric characteristics
of
HST and the broad range in wavelength coverage of the WFC3 to make
broad-band
vis/IR spectral observations of a large sample of Kuiper belt
objects.
Though the survey is currently only ~50% complete, the quality
and
unprecedented signal-to-noise of these observations has revealed the
existence
of a previously undiscovered spectral variability not
explainable
within our current understanding of these objects.
A
possible explanation for this variability is that with this faint set
of
Kuiper belt objects, we are beginning to see the difference between
larger
differentiated objects and smaller non-differentiated objects.
Its
seems that the small and likely undifferentiated objects are
exhibiting
silicate features that affect our photometry - features not
exhibited
by the icy mantles of larger icy bodies.
We
propose a small add-on survey to dramatically increase the scientific
results
of our large program. The proposed observations will use the
proven
capabilities of WFC3 to make broad and narrow-band photometric
observations
to detect spectral features in the 1.0-1.3 micron range of
a
small subset of our sources. The 13 targets have been carefully
selected
to cover the range of spectral variability detected in our
large
program as well as sample the entire dynamical range and physical
sizes
of these targets. These observations will allow the identification
of
undifferentiated Kuiper belt objects by detection of their silicate
features.
As a probe for differentiation, these observations could
constrain
the natal locations of different Kuiper belt classes, a
constraint
currently unavailable to formation models. This small set of
observations
will allow the calibration of the spectral variability seen
in
our large program, and drastically enhance the scientific output of
our
full Cycle 17 sample.
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.
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/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.
WFC3/IR
12197
Evolution
in the Size-Luminosity Relation of HII regions in
Gravitationally-lensed
galaxies
The
gravitational magnification of distant galaxies by foreground
clusters
has enabled the first measurement of the size-luminosity
relation
for HII regions at redshift z~2-5. A significant offset is seen
in
this relation with respect to that determined locally. This
evolutionary
trend has been interpreted as possible evidence for a
dfferent
mode of star formation in the early universe. To test this
hypothesis,
we propose to image a sample of 7 lensed galaxies at
intermediate
redshifts, z~1.0-1.5, carefully chosen so that the Halpha
emission
falls precisely within an appropriate narrow-band fiter with
WFC3/IR.
As each galaxy is magnified by a significant factor, this will
enable
us to resolve and measure the luminosities of ~50 individual HII
regions
as small as 50 pc to a star formation rate limit of 0.015
Mo/year.
By tracking the size-luminosity relation over the full redshift
range
from 0 to 5, we can differentiate between various explanations
proposed
for the change in this fundamental relationship.
WFC3/IR
12181
The
Atmospheric Structure of Giant Hot Exoplanets
Characterization
of close-in giant exoplanets has proceeded rapidly over
the
past few years, due largely to Spitzer and HST observations in
transiting
systems. Low resolution thermal emission spectra of over two
dozen
planets have been measured by Spitzer, and HST observations of a
few
key planets have indicated unusual molecular abundances via
transmission
spectroscopy. However, current models for the atmospheric
structure
of these worlds exhibit degeneracies wherein different
combinations
of temperature and molecular abundance profiles can fit the
same
Spitzer data for each planet. Fortunately, the advent of the IR
capability
on HST/WFC3 allows us to solve this major problem in
exoplanet
science. We propose to inaugurate a Large HST program that is
scientifically
complementary to Spitzer, Kepler, and CoRoT exoplanet
results.
We
will obtain transmission spectroscopy of the 1.4-micron water band in
a
sample of 13 planets, using the G141 grism on WFC3. Among the abundant
molecules,
only water absorbs at this wavelength, and our measurement of
water
abundance will enable us to break the degeneracies in the Spitzer
results
with minimal model assumptions. We will also use the G141 grism
to
observe secondary eclipses for 7 very hot giant exoplanets at
1.5-microns,
including several bright systems in the Kepler and CoRoT
fields.
The strong temperature sensitivity of the thermal continuum at
1.5-microns
provides high leverage on atmospheric temperature for these
worlds,
again helping to break degeneracies in interpreting the Spitzer
data.
Moreover, our precise eclipse photometry, in combination with
extant
Spitzer data, will enable us to extrapolate the thermal continuum
to
optical wavelengths. Kepler and CoRoT teams will be thereby able to
subtract
the thermal contribution from their increasingly precise
measurements
of optical eclipses, and measure, or place extremely
stringent
limits on, the albedo of these exotic worlds.
COS/NUV/FUV
12178
Spanning
the Reionization History of IGM Helium: a Highly Efficient
Spectral
Survey of the Far- UV-Brightest Quasars
The
reionization of IGM helium likely occurred at redshifts of z=3 to 4.
Detailed
studies of HeII Ly-alpha absorption toward a handful of quasars
at
2.7<z<3.3 confirm the potential of such IGM probes, but the small
sample
and redshift range limited confidence in cosmological inferences.
The
requisite unobscured sightlines to high redshift are extremely rare;
but
we've cross-correlated 10, 000 z>2.8 SDSS DR7 (and other) quasars
with
GALEX GR4/5, to identify 630 candidates potentially useful for HST
HeII
studies. Our cycle 15-16 HST trials confirm our approach, verifying
twenty
new HeII quasars at unprecedented 40% efficiency. We propose to
complete
the first efficient (80% with refinements) survey for HeII
quasars,
via reconnaissance (~1 orbit) COS spectra of a highly select
subset
of 17 SDSS/GALEX quasars at 2.7<z<3.8. Along with past work, this
program
will yield 3-4 of the brightest far-UV HeII sightlines within
each
of 10-12 redshift bins spanning 2.7<z<3.8, enabling a community
sample
suitable for detailed spectral follow-up with HST. Herein, we
will
also directly obtain quality UV spectral stacks within each
redshift
bin to trace the reionization history of IGM helium; such
spectral
stacks average over cosmic variance and individual object
pathology.
Our high-yield HeII sightline sample and spectral stacks will
enable
confident conclusions about the IGM baryon density, the spectrum
and
evolution of the ionizing background, the evolution of HeII opacity,
and
the epoch of helium reionization.
ACS/WFC
12166
A
Snapshot Survey of The Most Massive Clusters of Galaxies
We
propose the continuation of our highly successful HST/ACS SNAPshot
survey
of a sample of 123 very X-ray luminous clusters in the redshift
range
0.3-0.7, detected and compiled by the MACS cluster survey. As
demonstrated
by dedicated HST observations of the 12 most distant MACS
clusters
(GO-09722) as well as by the MACS SNAPshots of an additional 25
obtained
with ACS so far in Cycles 14 and 15, these systems frequently
exhibit
strong gravitational lensing as well as spectacular examples of
violent
galaxy evolution. A large number of additional MACS SNAPs have
since
been obtained with WFPC2, leading to the discovery of several more
powerful
cluster lenses. The dramatic loss, however, of depth,
field-of-view,
and angular resolution compared to ACS led to
significantly
reduced scientific returns, underlining the need for ACS
for
this project. The proposed observations will provide important
constraints
on the cluster mass distributions, on the physical nature of
!
galaxy-galaxy and galaxy-gas interactions in cluster cores, and will
yield
a set of optically bright, lensed galaxies for further 8-10m
spectroscopy.
For those of our targets with existing ACS SNAPshot
images,
we propose SNAPshots in the WFC3 F110W and F140W passbands to
obtain
colour information that will greatly improve the secure
identification
of multiple-image systems and may, in the form of F606W
or
F814W dropouts, lead to the lensing-enabled discovery of very distant
galaxies
at z>5. Acknowledging the broad community interest in this
sample
(16 of the 25 targets of the approved MCT cluster program are
MACS
discoveries) we waive our data rights for these observations.
This
proposal is an updated and improved version of our successful Cycle
15
proposal of the same title. Alas, SNAP-10875 collected only six
snapshots
in the F606W or F814W passbands, due to, first, a clerical
error
at STScI which caused the program to be barred from execution for
four
months and, ultimately, the failure of ACS. With ACS restored, and
WFC3
providing additional wavelength and redshift leverage, we wish to
resume
this previously approved project.
WFC3/IR/WFC/ACS/UV
12061
Cosmic
Assembly Near-IR Deep Extragalactic Legacy Survey -- GOODS-South
Field,
Early Visits of SNe Search
This
survey will document the first third of galactic evolution from z=8
to
1.5 and test for evolution in the properties of Type Ia supernovae to
z~2
by imaging more than 250, 000 galaxies with WFC3/IR and ACS. Five
premier
multi-wavelength regions are selected from within the Spitzer
SEDS
survey, providing complementary IRAC data down to 26.5 AB mag, a
unique
resource for stellar masses at high redshifts. The use of five
widely
separated fields mitigates cosmic variance and yields
statistically
robust samples of galaxies down to 10^9 M_Sun out to z~8.
We
adopt a two-tiered strategy with a "Wide" component (roughly 2 orbits
deep
over ~0.2 sq. degrees) and a "Deep" component (roughly 12 orbits
deep
over ~0.04 sq. degrees). Combining these with ultra-deep imaging
from
the Cycle 17 HUDF09 program yields a three-tiered strategy for
efficient
sampling of both rare/bright and faint/common objects.
Three
of the Wide-survey fields are located in COSMOS, EGS, and
UKIDSS/UDS.
Each of these consists of roughly 3x15 WFC3/IR tiles. Each
WFC3
tile will be observed for 2 orbits, with single orbits separated in
time
to allow a search for high-redshift Type Ia SNe. The co-added
exposure
times will be approximately 2/3 orbit in J (F125W) and 4/3
orbit
in H (F160W). ACS parallels overlap most of the WFC3 area and will
consist
of roughly 2/3 orbits in V (F606W) and 4/3 orbit in I (F814W).
Because
of the larger area of ACS, this results in effective exposures
that
are twice as long (4/3 in V, 8/3 in I), making a very significant
improvement
to existing ACS mosaics in COSMOS and EGS and creating a new
ACS
mosaic in UDS/UKIDSS where none now exists. Other Wide-survey
components
are located in the GOODS fields (North and South) surrounding
the
Deep-survey areas.
The
Deep-survey fields cover roughly half of each GOODS field, with
exact
areas and placements to be determined as part of the Phase-2
process.
Each WFC3/IR tile within the Deep regions will receive
approximately
12 orbits of exposure time split between Y (F105W), J
(F125W),
and H (F160W). Multi-epoch imaging will provide an efficient
search
for high-redshift Type Ia SNe here also. ACS parallels are also
taken
in the Deep regions, with the goal of assembling enough total
exposure
time in F850LP and other filters to identify high redshift z>6
galaxies
in concert with WFC3/IR data using the Lyman break technique.
A
portion of the GOODS-N campaign will take place while the field is in
the
HST Continuous Viewing Zone (CVZ). The bright time in those orbits
will
be used to obtain UV imaging with WFC3 in the F275W and F336W
filters.
The exact number of orbits will not be known until Phase-2
planning
is complete, but we anticipate that it will be possible to
schedule
at least 100 orbits, resulting in 5-sigma point-source depths
of
26.6, 26.4 in F275W and F336W, respectively. The science goals
include
measuring the Lyman-continuum escape fractions for galaxies at
z~2.5
and identifying Lyman-break galaxies at z~2-3.
The
Type Ia supernova search program in this proposal is integrated with
that
in the Postman cluster MCT proposal, with this one stressing the
more
distant supernovae. A combined follow-up program will provide light
curves
and grism spectra of 15-20 of the best candidates at redshifts
1<z<2.
The observing configuration for the follow up will depend on the
redshift
of the supernova, and will likely include a grism observation
with
either ACS G800L, WFC3-IR G102, or G141, and light curves observed
with
F850LP, WFC3-IR F125W, and F160W.
The
new data will be used to answer many urgent questions in galaxy
evolution
and cosmology. In the reionization era, we will identify
hundreds
of high-confidence z>7 galaxies in the Deep regions, in
addition
to hundreds of highly-luminous candidates in the Wide regions
for
detailed follow-up. These samples will be used to construct a
unified
picture of star-formation and stellar mass buildup in early
galaxies.
Extremely deep X-ray data will reveal distant AGNs to z>6,
shedding
light on the earliest stages of BH growth. In the peak star
formation/QSO
era, z~2, we will document the properties of early disks,
the
build-up of bulges, the evolution of mergers, and the nature of AGN
hosts
to construct an integrated model for structural evolution, star
formation
quenching, and AGN triggering. Finally, the ~8 Type Ia SNe
found
beyond z>1.5 in the supernova programs will establish the
constancy
of these standard candles independent of dark energy and yield
the
first measurement of the Type Ia rate at z~2 to distinguish among
different
progenitor models. Lower-redshift SNe Ia at 1<z<1.5 will be
used
to measure the evolution of dark energy.
This
program takes full advantage of MCTP mode to fulfill Hubble's
legacy
for deep extragalactic science and prepare the way for JWST.
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 will 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.
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.
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/UVIS
11907
UVIS
Cycle 17 Contamination Monitor
The
UV throughput of WFC3 during Cycle 17 is monitored via weekly
standard
star observations in a subset of key filters covering 200-600nm
and
F606W, F814W as controls on the red end. The data will provide a
measure
of throughput levels as a function of time and wavelength,
allowing
for detection of the presence of possible contaminants.
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).
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/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.
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.
STIS/CCD
11845
CCD
Dark Monitor Part 2
Monitor
the darks for the STIS CCD.
STIS/CCD
11721
Verifying
the Utility of Type Ia Supernovae as Cosmological Probes:
Evolution
and Dispersion in the Ultraviolet Spectra
The
study of distant type Ia supernova (SNe Ia) offers the most
practical
and immediate discriminator between popular models of dark
energy.
Yet fundamental questions remain over possible
redshift-dependent
trends in their observed and intrinsic properties.
High-quality
Keck spectroscopy of a representative sample of 36
intermediate
redshift SNe Ia has revealed a surprising, and unexplained,
diversity
in their rest-frame UV fluxes. One possible explanation is
hitherto
undiscovered variations in the progenitor metallicity.
Unfortunately,
this result cannot be compared to local UV data as only
two
representative SNe Ia have been studied near maximum light. Taking
advantage
of two new `rolling searches' and the restoration of STIS, we
propose
a non-disruptive TOO campaign to create an equivalent comparison
local
sample. This will allow us to address possible evolution in the
mean
UV spectrum and its diversity, an essential precursor to the study
of
SNe beyond z~1.
WFC3/IR
11694
Mapping
the Interaction Between High-Redshift Galaxies and the
Intergalactic
Environment
With
the commissioning of the high-throughput large-area camera WFC3/IR,
it
is possible for the first time to undertake an efficient survey of
the
rest-frame optical morphologies of galaxies at the peak epoch of
star
formation in the universe. We therefore propose deep WFC3/IR
imaging
of over 320 spectroscopically confirmed galaxies between
redshift
1.6 < z < 3.4 in well-studied fields which lie along the line
of
sight to bright background QSOs. The spectra of these bright QSOs
probe
the IGM in the vicinity of each of the foreground galaxies along
the
line of sight, providing detailed information on the physical state
of
the gas at large galactocentric radii. In combination with our
densely
sampled UV/IR spectroscopy, stellar population models, and
kinematic
data in these fields, WFC3/IR imaging data will permit us to
construct
a comprehensive picture of the structure, dynamics, and star
formation
properties of a large population of galaxies in the early
universe
and their effect upon their cosmological environment.
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.
ACS/WFC3
11575
The
Stellar Origins of Supernovae
Supernovae
(SNe) have a profound effect on galaxies, and have been used
recently
as precise cosmological probes, resulting in the discovery of
the
accelerating Universe. They are clearly very important events
deserving
of intense study. Yet, even with nearly 4000 known SNe, we
know
relatively little about the stars which give rise to these powerful
explosions.
The main limitation has been the lack of spatial resolution
in
pre-SN imaging data. However, since 1999 our team has been at the
vanguard
of directly identifying SN progenitor stars in HST images. From
this
exciting new line of study, the emerging trend from 5 detections
for
Type II- Plateau SNe is that their progenitors appear to be
relatively
low mass (8 to 20 Msun) red supergiants, although more cases
are
needed. Nonetheless, the nature of the progenitors of Type Ib/c SNe,
a
subset of which are associated with the amazing gamma-ray bursts,
remains
ambiguous. Furthermore, we remain in the continually
embarrassing
situation that we still do not yet know which progenitor
systems
explode as Type Ia SNe, which are currently being used for
precision
cosmology. In Cycle 16 we have triggered on the Type Ic SN
2007gr
and Type IIb SN 2008ax so far. We propose to determine the
identities
of the progenitors of 4 SNe within 17 Mpc, which we expect to
occur
during Cycle 17, through ToO observations using ACS/HRC.
COS/NUV/FUV
11532
COS-GTO:
Activity of Solar Mass Stars from Cradle to Grave
COS
spectra will be very useful for answering the question of how
chromospheric
and coronal activity of stars decline as stars lose
angular
momentum and magnetic fields with age. This question is
important
for modeling the atmospheres of young planets that are blasted
by
strong ultraviolet radiation and winds from young stars. COS will
obtain
spectra of solar mass stars with a range of ages from 10 Myr to 7
Gyr.