HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5131
PERIOD
COVERED: 5am July 2 - 5am July 6, 2010 (DOY 183/09:00z-187/09:00z)
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
27
27
FGS
REAcq
32
32
OBAD with
Maneuver
20
20
SIGNIFICANT
EVENTS: (None)
OBSERVATIONS
SCHEDULED:
STIS/CCD 11999
JWST
Calibration from a Consistent Absolute Calibration of Spitzer &
Hubble
Recently,
Gordon, Bohlin, et al. submitted a successful Spitzer proposal
for cross
calibration of HST and Spitzer. The cross-calibration targets
are stars
in three categories: WDs, A-stars, and G-stars. Traditionally,
IR flux
standards are extrapolations of stellar models that are tied to
absolute
fluxes at shorter wavelengths. HST absolute flux standards are
among the
best available with a solid basis that uses pure hydrogen
models of
hot WD stars for the SED slopes and is tied to Vega at 5556A
via precise
Landolt V-band photometry. Consistently matching models to
our three
categories of HST observations along with Spitzer photometry
and the few
existing absolute IR flux determinations will provide a
solid basis
for JWST flux calibration over its 0.8-30micron range. The
goal of
this proposal is to complete the HST observations of the set of
HST/Spitzer
cross-calibration stars. Using a variety of standard stars
with three
different spectral types will ensure that the final
calibration
is not significantly affected by systematic uncertainties.
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/IR
11926
IR Zero
Points
We will
measure and monitor the zeropoints through the IR filters using
observations
of the white dwarf standard stars, GD153, GD71 and GD191B2B
and the
solar analog standard star, P330E. Data will be taken monthly
during
Cycle 17. Observations of the star cluster, NGC 104, are made
twice to check
color transformations. We expect an accuracy of 2% in the
wide filter
zeropoints relative to the HST photometric system, and 5% in
the medium-
and narrow-band filters.
WFC3/IR
11915
IR Internal
Flat Fields
This
program is the same as 11433 (SMOV) and depends on the completion
of the IR
initial alignment (Program 11425). This version contains three
instances
of 37 internal orbits: to be scheduled early, middle, and near
the end of
Cycle 17, in order to use the entire 110-orbit allocation.
In this
test, we will study the stability and structure of the IR
channel
flat field images through all filter elements in the WFC3-IR
channel.
Flats will be monitored, i.e. to capture any temporal trends in
the flat
fields and delta flats produced. High signal observations will
provide a
map of the pixel-to-pixel flat field structure, as well as
identify
the positions of any dust particles.
WFC3/UVIS
11911
UVIS
L-Flats and Geometric Distortion
Multiple
pointing observations of the globular cluster Omega Centauri
(NGC 5139)
will be used to measure the filter-dependent low frequency
flat field
(L-flat) corrections and stability for a key set of 10
broadband
filters used by GO programs. The selected filters are F225W,
F275W, F336W,
F390W, F438W, F555W, F606W, F775W, F814W and F850LP. By
measuring
relative changes in brightness of a star over different
portions of
the detector, we will determine local variations in the UVIS
detector
response.
The broad
wavelength range covered by these observations will allow us
to derive
the L-flat correction for the remaining wide, medium and
narrow-band
UVIS filters. The same data will also be used to determine
and correct
the geometric distortion that affects UVIS data. The broad
wavelength
range covered by these observations will allow us to measure
the
geometric distortion dependence with wavelength and filters and to
provide the
most appropriate correction over the entire wavelength range
provided by
UVIS.
WFC3/UVIS
11908
Cycle 17: 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/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
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
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.
ACS/SBC
11886
UV
Contamination Monitor
The
observations consist of imaging and spectroscopy with SBC and HRC of
the cluster
NGC 6681 in order to monitor the temporal evolution of the
UV
sensitivity of the SBC and the HRC.
WFC3/ACS/UVIS
11877
HST Cycle
17 and Post-SM4 Optical Monitor
This
program is the Cycle 17 implementation of the HST Optical
Monitoring
Program.
The 36
orbits comprising this proposal will utilize ACS (Wide Field
Channel)
and WFC3 (UVIS Channel) to observe stellar cluster members in
parallel
with multiple exposures over an orbit. Phase retrieval
performed
on the PSF in each image will be used to measure primarily
focus, with
the ability to explore apparent coma, and astigmatism
changes in
WFC3.
The goals
of this program are to: 1) monitor the overall OTA focal
length for
the purposes of maintaining focus within science tolerances
2) gain
experience with the relative effectiveness of phase retrieval on
WFC3/UVIS
PSFs 3) determine focus offset between the imagers and
identify
any SI-specific focus behavior and dependencies
If need is
determined, future visits will be modified to interleave
WFC3/IR
channel and STIS/CCD focii measurements.
STIS/CCD
11855
STIS/CCD
Spectroscopic Sensitivity Monitor for Cycle 17
Monitor
sensitivity of each CCD grating mode to detect any change due to
contamination
or other causes.
STIS/CC
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/CC
11845
CCD Dark
Monitor Part 2
Monitor the
darks for the STIS CCD.
WFC3/UV/ACS/WFC
11739
Multiple
Stellar Generations in the Unique Globular Clusters NGC 6388
and NGC
6441
Over the
last few years HST observations have resulted in one of the
most exciting
and unexpected developments in stellar population studies:
the
discovery of multiple generations of stars in several globular
clusters.
The finding of multiple main sequences in the massive clusters
NGC 2808
and Omega Centauri, and multiple subgiant branches in NGC 1851,
M54, and
NGC 6388 has challenged the long-held paradigm that globular
clusters
are simple stellar populations. Even more surprising, given the
spectroscopic
and photometric constraints, the only viable explanation
for the
main sequence splitting appears to be Helium enrichment, up to
an
astonishingly high Y=0.4. The conditions under which certain
globulars
experience the formation of multiple stellar generations
remain
mysterious, and even more so the helium-enrichment phenomenon.
Such an
enrichment has important implications for chemical-enrichment,
star-formation,
and stellar-evolution scenarios, in star clusters and
likely
elsewhere. To properly constrain the multiple main sequence
phenomenon,
it is important to determine its extent among GCs: is it
limited to
Omega Cen and NGC2808, or is it more common? We propose deep
WFC3
optical/IR imaging of NGC 6388 and 6441, the two globular clusters
that are
most likely to host multiple, helium-enriched populations. Our
simulations
of WFC3 performance suggest that we will be able to detect
even the
main sequence splittings caused by small He differences (Delta
Y
<0.03).
WFC3/UVIS
11732
The
Temperature Profiles of Quasar Accretion Disks
We can now
routinely measure the size of quasar accretion disks using
gravitational
microlensing of lensed quasars. At optical wavelengths we
observe a
size and scaling with black hole mass roughly consistent with
thin disk
theory but the sizes are larger than expected from the
observed
optical fluxes. One solution would be to use a flatter
temperature
profile, which we can study by measuring the wavelength
dependence
of the disk size over the largest possible wavelength
baseline.
Thus, to understand the size discrepancy and to probe closer
to the
inner edge of the disk we need to extend our measurements to UV
wavelengths,
and this can only be done with HST. For example, in the UV
we should
see significant changes in the optical/UV size ratio with
black hole
mass. We propose monitoring 5 lenses spanning a broad range
of black
hole masses with well-sampled ground based light curves,
optical
disk size measurements and known GALEX UV fluxes during Cycles
17 and 18
to expand from our current sample of two lenses. We would
obtain 5 observations
of each target in each Cycle, similar to our
successful
strategy for the first two targets.
WFC3/UV/ACS/WFC
11710
The Extreme
Globular Cluster System of Abell 1689: The Ultimate Test of
Universal
Formation Efficiency
The stellar
masses of the most luminous galaxies poorly represent the
masses of
the halos in which they reside. However, recent studies of the
very rich
globular cluster (GC) populations in the centers of galaxy
clusters
point toward an apparently linear scaling of the number of GCs
with the
total core mass of the galaxy cluster. Thus, unlike for the
stars in cD
galaxies, GC formation in these systems appears to have
proceeded
with a roughly universal mass conversion efficiency. GCs are
also
distinct in that their spatial distributions are more extended than
the
starlight, and recent simulations suggest that they follow the mass
density
profile of the merged dark matter halos that formed stars at
high
redshift. To provide a definitive test of the universal efficiency
hypothesis
requires measuring the number of GCs in the most massive
galaxy
clusters, where the number should be a factor of 5 or more
greater
than seen in M87. Likewise, the relationship between GCs and
mass
density can only be tested in systems where the total mass and mass
density are
well-determined. Fortunately, the imaging power of HST
brings the
GC population of Abell 1689, the most extreme high-mass
lensing
cluster, into range. Estimates of the size of the A1689 GC
population
from available data suggest an unprecedented 100, 000 GCs,
but this
number is based on the tip of the iceberg and is extremely
uncertain.
We propose to obtain the first accurate measurement of the
number of
GCs and their density profile in this extraordinary system -
the most massive
and most distant GC system ever studied - and thus make
the
ultimate test of the universal GC formation hypothesis. Our deep
I-band
image will also provide a stringent "null-detection" test of
several
known z>7 galaxy candidates and improve the mass model of the
system by
increasing the number of usable lensed background galaxies.
Finally, we
will take deep multi-band parallel observations with WFC3/IR
to help in
quantifying the abundance of rare faint red objects.
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/UVIS
11661
The Black
Hole Mass - Bulge Luminosity Relationship for the Nearest
Reverberation-Mapped
AGNs
We propose
to obtain WFC3 host galaxy images of the eight nearest AGNs
with masses
from reverberation mapping, and one star as a PSF model.
These
images will allow us to determine with unprecedented accuracy the
bulge
luminosities of the host galaxies, a goal which is not achievable
from the
ground due to the blurring of the very bright PSF component
under
typical, and even very good, seeing conditions. High-resolution
ACS images
of the host galaxies of more luminous AGNs reveal that the
black hole
mass-bulge luminosity and black hole mass-bulge mass
relationships
for AGNs are not well constrained and arise from what
appear to
be fundamentally flawed data sets. With the addition of the
images
proposed here to our current sample of ACS images, we will be
able to
extend our determinations of the black hole mass- bulge
luminosity and
black hole mass-bulge mass relationships for AGNs by an
order of
magnitude and test our preliminary results for these
fundamentally
important relationships against those previously
determined
for quiescent galaxies.
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/UVI
11615
Hunting for
Optical Companions to Binary MSPs in Globular Clusters
Here we
present a proposal which exploits the re-newed potential of HST
after the
Service Mission 4 for probing the population of binary
Millisecond
Pulsars (MSPs) in Globular Clusters. In particular we intend
to: (1)
extend the search for optical counterparts in Terzan 5, by
pushing the
performance of the WFC3 IR channel to sample the entire MS
extension
down to M=0.1 Mo; (2) perform a deep multi-band search of MSP
companions
with the WFC3, in 3 clusters (namely NGC6440, M28 and M5),
where
recent radio observations have found particularly interesting
objects;
(3) derive an accurate radial velocity (with STIS) of the
puzzling
optical companion COM6266B recently discovered by our group, to
firmly
assess its cluster membership. This program is the result of a
large
collaboration among the three major groups (lead by Freire, Ransom
and
Possenti) which are performing extensive MSP search in GCs in the
radio
bands, and our group which has a large experience in performing
accurate
stellar photometry in crowded environments. This collaboration
has
produced a number of outstanding discoveries. In fact, three of the
6 optical
counterparts to binary MSP companions known to date in GCs
have been
discovered by our group. The observations here proposed would
easily
double/triple the existing sample of known MSP companions,
allowing
the first meaningful approach to the study of the formation,
evolution
and recycling process of pulsar in GCs. Moreover, since most
of binary
MSPs in GCs are thought to form via stellar interactions in
the high
density core regions, the determination of the nature of the
companion
and the incidence of this collisionally-induced population has
a significant
impact on our knowledge of the cluster dynamics. Even more
interesting,
the study of the optical companions to NSs in GCs allows
one to
derive tighter constraints (than those obtainable for NS binaries
in the
Galactic field) on the system properties. This has, in turn, an
intrisic
importance for fundamental physics, since it offers the
opportunity
of measuring the mass of the NS and hence constraining the
equation of
state of matter at the nuclear equilibrium density.
WFC3/UV
11605
Obtaining
the Missing Links in the Test of Very Low Mass Evolutionary
Models with
HST
We are
proposing for spatially resolved ACS+HRC observations of 11 very
low mass
binaries spanning late-M, L and T spectral types in order to
obtain
precise effective temperature measurements for each component.
All of our
targets are part of a program in which we are measuring
dynamical
masses of very low-mass binaries to an unprecedented precision
of 10% (or
better). However, without precise temperature measurements,
the full scientific
value of these mass measurements cannot be realized.
Together,
mass and temperature measurements will allow us to distinguish
between
brown dwarf evolutionary models that make different assumptions
about the
interior and atmospheric structure of these ultra-cool
objects.
While dynamical masses can be obtained from the ground in the
near-IR,
obtaining precise temperatures require access to optical data
which, for
these sub-arcsecond binaries, can only be obtained from space
with
Hubble.
WFC3/ACS/UVIS
11603
A
Comprehensive Study of Dust Formation in Type II Supernovae with HST,
Spitzer,
and Gemini
The recent
discovery of three extremely bright Type II SNe, (2007it,
2007oc,
2007od) gives us a unique opportunity to combine observations
with HST,
Spitzer, and Gemini to study the little understood dust
formation
process in Type II Sne. Priority 1 Spitzer Cycle 5 and band 1
Gemini
2008A time has already been approved for this project. Since
late-time
Type II Sne are faint and tend to be in crowded fields, we
need the
high sensitivity and high spatial resolution of ACS and
NICMOS/NIC2
for these observations. This project is motivated by the
recent
detection of large amounts of dust in high redshift galaxies. The
dust in
these high-z galaxies must come from young, massive stars so
Type II Sne
could be potential sources. The mechanism and the efficiency
of dust
condensation in Type II SN ejecta are not well understood,
largely due
to the lack of observational data. We plan to produce a
unique dataset,
combining spectroscopy and imaging in the visible, near-
and mid-IR
covering the key phase, 400-700 days after maximum when dust
is known to
form in the SN ejecta. Therefore, we are proposing for
coordinated
HST/NOAO observations (HST ACS, NICMOS/NIC2 & Gemini/GMOS
and TReCS)
which will be combined with our Spitzer Cycle 5 data to study
these new
bright Sne. The results of this program will place strong
constraints
on the formation of dust seen in young high redshift (z>5)
galaxies.
COS/NUV/FUV
11598
How
Galaxies Acquire their Gas: A Map of Multiphase Accretion and
Feedback in
Gaseous Galaxy Halos
We propose
to address two of the biggest open questions in galaxy
formation -
how galaxies acquire their gas and how they return it to the
IGM - with a
concentrated COS survey of diffuse multiphase gas in the
halos of
SDSS galaxies at z = 0.15 - 0.35. Our chief science goal is to
establish a
basic set of observational facts about the physical state,
metallicity,
and kinematics of halo gas, including the sky covering
fraction of
hot and cold material, the metallicity of infall and
outflow,
and correlations with galaxy stellar mass, type, and color -
all as a
function of impact parameter from 10 - 150 kpc. Theory suggests
that the
bimodality of galaxy colors, the shape of the luminosity
function,
and the mass-metallicity relation are all influenced at a
fundamental
level by accretion and feedback, yet these gas processes are
poorly
understood and cannot be predicted robustly from first
principles.
We lack even a basic observational assessment of the
multiphase
gaseous content of galaxy halos on 100 kpc scales, and we do
not know
how these processes vary with galaxy properties. This ignorance
is
presently one of the key impediments to understanding galaxy
formation
in general. We propose to use the high-resolution gratings
G130M and
G160M on the Cosmic Origins Spectrograph to obtain sensitive
column
density measurements of a comprehensive suite of multiphase ions
in the
spectra of 43 z < 1 QSOs lying behind 43 galaxies selected from
the Sloan
Digital Sky Survey. In aggregate, these sightlines will
constitute
a statistically sound map of the physical state and
metallicity
of gaseous halos, and subsets of the data with cuts on
galaxy
mass, color, and SFR will seek out predicted variations of gas
properties
with galaxy properties. Our interpretation of these data will
be aided by
state-of-the-art hydrodynamic simulations of accretion and
feedback,
in turn providing information to refine and test such models.
We will
also use Keck, MMT, and Magellan (as needed) to obtain optical
spectra of
the QSOs to measure cold gas with Mg II, and optical spectra
of the
galaxies to measure SFRs and to look for outflows. In addition to
our other
science goals, these observations will help place the Milky
Way's
population of multiphase, accreting High Velocity Clouds (HVCs)
into a
global context by identifying analogous structures around other
galaxies.
Our program is designed to make optimal use of the unique
capabilities
of COS to address our science goals and also generate a
rich
dataset of other absorption-line systems.
WFC3/ACS/IR
11597
Spectroscopy
of IR-Selected Galaxy Clusters at 1 < z < 1.5
We propose
to obtain WFC3 G141 and G102 slitless spectroscopy of galaxy
clusters at
1 < z < 1.5 that were selected from the IRAC survey of the
Bootes
NDWFS field. Our IRAC survey contains the largest sample of
spectroscopically
confirmed clusters at z > 1. The WFC3 grism data will
measure
H-alpha to determine SFR, and fit models to the low resolution
continua to
determine stellar population histories for the brighter
cluster
members, and redshifts for the red galaxies too faint for
ground-based
optical spectroscopy.
ACS/WFC3
11586
Exceptional
Galactic Halo Globular Clusters and the Second Parameter
We propose
to obtain deep ACS-WFC images of six globular clusters (five
of which
have no previous HST photometry) that reside in the Galactic
halo, where
the second parameter effect is most pronounced. These
globular clusters
are among the least studied in the Galaxy and yet,
from the
perspective of the second parameter phenomenon, the most
intriguing.
With the
best available CMDs only reaching the vicinity of the main
sequence
turn off at present, the unique sensitivity and resolution of
ACS-WFC
will yield ages of unprecedented precision for these clusters.
These data
will provide us with new insight into the stellar populations
present in
the outer Galactic halo and the nature of the second
parameter.
The second parameter plays a critical role in our
understanding
of the formation and evolution of the Galaxy and the
proposed
observations will shed new light on this problem and these
exceptional
clusters.
ACS/WFC
11582
The Spatial
Distribution of Radiation in the Complex ISM of Distant
Ultraluminous
Galaxies
A
significant fraction of energy emitted by galaxies at redshifts when
their stars
were forming most vigorously, and when their blackholes were
growing
most powerfully emerges at far-infrared (IR) wavelengths. The
fraction of
this energy generated by the most extreme and luminous
objects is
also much larger than the equivalent fraction at optical
wavelengths.
Many of the most luminous far-IR sources have been located
precisely and
unambiguously using deep radio, Spitzer and optical
observations,
and have spectroscopic identifications using the largest
ground-based
telescopes. Surprisingly, however, the spectra of most of
these
heavily dust-enshrouded galaxies show prominent Lyman-alpha
emission.
We propose to observe five of the brightest examples at z~2-3
in
re-activated ACS ramp filters, to resolve the spatial distribution of
this line
emission on fine kpc scales, in order to contrast and compare
with the
underlying ultraviolet (UV) continuum. Precise spectroscopic
redshifts
and the unique rest-UV resolution of HST are both essential to
reveal the
escape and generation of Lyman-alpha photons in the dusty ISM
of these
extreme galaxies. There is no other way to trace the detailed
spatial
distirbution of the most excited gas in a galactic wind, along
with
emission from less-massive star-forming galaxies in associated
groups. The
targets have available HST-resolution ground-based near-IR
AO imaging
and arcsec-scale images in CO from ground-based mm-wave
interferometers,
which provide context for spatial structure of evolved
stars and
the ISM. The interplay between restframe UV emission and the
ISM in
these galaxies has important consequences for understanding the
origin of
the prodigous luminosity of these systems, and for future
observations
with JWST and ALMA.
ACS/SBC/COS/NUV/FUV
11579
The
Difference Between Neutral- and Ionized-Gas Metal Abundances in
Local
Star-Forming Galaxies with COS
The
metallicity of galaxies and its evolution with redshift is of
paramount
importance for understanding galaxy formation. Abundances in
the
interstellar medium (ISM) are typically determined using
emission-line
spectroscopy of HII regions. However, since HII regions
are associated
with recent SF they may not have abundances typical for
the galaxy
as a whole. This is true in particular for star-forming
galaxies
(SFGs), in which the bulk of the metals may be contained in the
neutral
gas. It is therefore important to directly probe the metal
abundances
in the neutral gas. This can be done using absorption lines
in the Far
UV. We have developed techniques to do this in SFGs, where
the
absorption is measured for sightlines toward bright SF regions
within the
galaxy itself. We have successfully applied this technique to
a sample of
galaxies observed with FUSE. The results have been very
promising,
suggesting in I Zw 18 that abundances in the neutral gas may
be up to
0.5 dex lower than in the ionized gas. However, the
interpretation
of the FUSE data is complicated by the very large FUSE
aperture
(30 arcsec), the modest S/N, and the limited selection of
species
available in the FUSE bandpass. The advent of COS on HST now
allows a
significant advance in all of these areas. We will therefore
obtain
absorption line spectroscopy with G130M in the same sample for
which we
already have crude constraints from FUSE. We will obtain
ACS/SBC
images to select the few optimal sightlines to target in each
galaxy. The
results will be interpreted through line-profile fitting to
determine
the metal abundances constrained by the available lines. The
results
will provide important new insights into the metallicities of
galaxies,
and into outstanding problems at high redshift such as the
observed
offset between the metallicities of Lyman Break Galaxies and
Damped
Lyman Alpha systems.
WFC3/UV
11556
Investigations
of the Pluto System
We propose
a set of high SNR observations of the Pluto system that will
provide improved
lightcurves, orbits, and photometric properties of Nix
and Hydra.
The key photometric result for Nix and Hydra will be a vastly
improved
lightcurve shape and rotation period to test if the objects are
in
synchronous rotation or not. A second goal of this program will be to
retrieve a
new epoch of albedo map for the surface of Pluto. These
observations
will also improve masses and in some case densities for the
bodies in
the Pluto system.
WFC3/ACS/UVIS
11360
Star
Formation in Nearby Galaxies
Star
formation is a fundamental astrophysical process; it controls
phenomena
ranging from the evolution of galaxies and nucleosynthesis to
the origins
of planetary systems and abodes for life. The WFC3,
optimized
at both UV and IR wavelengths and equipped with an extensive
array of
narrow-band filters, brings unique capabilities to this area of
study. The
WFC3 Scientific Oversight Committee (SOC) proposes an
integrated
program on star formation in the nearby universe which will
fully
exploit these new abilities. Our targets range from the
well-resolved
R136 in 30 Dor in the LMC (the nearest super star cluster)
and M82
(the nearest starbursting galaxy) to about half a dozen other
nearby
galaxies that sample a wide range of star-formation rates and
environments.
Our program consists of broad band multiwavelength imaging
over the
entire range from the UV to the near-IR, aimed at studying the
ages and
metallicities of stellar populations, revealing young stars
that are
still hidden by dust at optical wavelengths, and showing the
integrated
properties of star clusters. Narrow-band imaging of the same
environments
will allow us to measure star-formation rates, gas
pressure,
chemical abundances, extinction, and shock morphologies. The
primary scientific
issues to be addressed are: (1) What triggers star
formation?
(2) How do the properties of star-forming regions vary among
different
types of galaxies and environments of different gas densities
and
compositions? (3) How do these different environments affect the
history of
star formation? (4) Is the stellar initial mass function
universal
or determined by local conditions?
-Lynn
NASA
office: 301-286-2876
__________________________________________________________
Lynn F. Bassford
Hubble Space Telescope
CHAMP Mission Operations Manager
CHAMP Flight Operations Team Manager
Lockheed Martin Mission Services (LMMS)
"...Hubble is the most
significant science instrument of all time in terms of its
productivity..." Scott Altman @12:45pm 5/21/9
STS-125 Senate Subcommittee Hearing