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Daily Report #5092



 
 
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Old May 10th 10, 02:41 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5092

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5092

PERIOD COVERED: 5am May 7 - 5am May 10, 2010 (DOY 127/09:00z-130/09:00z)

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

12270 - REAcq(1,2,1) at 129/19:25:47z took 3 attempts to succeed. the
first two attempts resulted in scan step limit exceeded on FGS1.
Previous GSAcq(1,2,1) at 129/17:58:12z was successful on the first
attempt.

12271 - GSAcq(2,0,2) at 130/06:34:11z failed to RGA control due to
scan step limit exceeded on FGS 2.

Observations affected: Astrometry proposal ID#11704.

COMPLETED OPS REQUEST:

18855-0 - Null Genslew for proposal 12077 - slot 1 @ 127/1911z

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 28 27
FGS REAcq 18 18
OBAD with Maneuver 18 18

SIGNIFICANT EVENTS: (None)




OBSERVATIONS SCHEDULED

WFC3/IR/S/C 12089

Persistence - Part 2

The IR detectors on WFC3, like other IR detectors, trap charge when
exposed to sources near or above the full well of the detector diodes.
This charge leaks out, producing detectable afterglow images for
periods which can last for several hours, depending on the amount of
over exposure. These visits, which consist of tungsten lamp exposures
of varying durations followed by darks, are intended to provide a
better calibration of persistence over the full area of the IR
detector of WFC3.

WFC3/UV 12077

Monitoring the Aftermath of an Asteroid Impact Event

Our Director's Discretionary program (GO-12053) to image the newly
discovered object P/2010 A2 executed successfully on 2010 Jan 25 and
29 with spectacular results. Hubble has apparently borne witness to
the first detection of a collision in the asteroid belt. Hubble
imaging with the WFC3 has revealed an object unlike anything ever seen
before and with details impossible to detect with any other facility.
We request 6 more orbits of Hubble time (1 orbit every 20 days over
the next few months, until the object enters Hubble's solar exclusion
zone in late-June 2010) to monitor the evolution of this remarkable
object and further clarify the nature of this event. These
observations may usher in a new era of searching for and
characterizing collisional events within the asteroid belt.

ACS/WFC 11995

CCD Daily Monitor (Part 2)

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 320 orbits (20 weeks) from 1 February
2010 to 20 June 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/UVIS 11924

WFC3/UVIS External and Internal CTE Monitor

CCD detector Charge Transfer Inefficiency (CTI)-induced losses in
photometry and astrometry will be measured using observations of the
rich open cluster NGC6791 and with the EPER (Extended Pixel Edge
Response) method using tungsten lamp flat field exposures. Although we
do not expect to see CTE effects at the outset of Cycle 17, this CTE
monitoring program is the first of a multi-cycle program to monitor
and establish CTE-induced losses with time. We expect to measure CTE
effects with a precision comparable to the ACS measurements.

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).

STIS/MA1 11861

MAMA FUV Flats

This program will obtain FUV-MAMA observations of the STIS internal
Krypton lamp to construct an FUV flat applicable to all FUV modes.

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/IR 11838

Completing a Flux-limited Survey for X-ray Emission from Radio Jets

We will measure the changing flow speeds, magnetic fields, and energy
fluxes in well-resolved quasar jets found in our short-exposure
Chandra survey by combining new, deep Chandra data with radio and
optical imaging. We will image each jet with sufficient sensitivity to
estimate beaming factors and magnetic fields in several distinct
regions, and so map the variations in these parameters down the jets.
HST observations will help diagnose the role of synchrotron emission
in the overall SED, and may reveal condensations on scales less than
0.1 arcsec.

FGS 11789

An Astrometric Calibration of Population II Distance Indicators

In 2002, HST produced a highly precise parallax for RR Lyrae. That
measurement resulted in an absolute magnitude, M(V)= 0.61+/-0.11, a
useful result, judged by the over ten refereed citations each year
since. It is, however, unsatisfactory to have the direct,
parallax-based, distance scale of Population II variables based on a
single star. We propose, therefore, to obtain the parallaxes of four
additional RR Lyrae stars and two Population II Cepheids, or W Vir
stars. The Population II Cepheids lie with the RR Lyrae stars on a
common K-band Period-Luminosity relation. Using these parallaxes to
inform that relationship, we anticipate a zero point error of 0.04
magnitude. This result should greatly strengthen confidence in the
Population II distance scale and increase our understanding of RR
Lyrae star and Pop. II Cepheid astrophysics.

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/IR 11719

A Calibration Database for Stellar Models of Asymptotic Giant Branch
Stars

Studies of galaxy formation and evolution rely increasingly on the
interpretation and modeling of near-infrared observations. At these
wavelengths, the brightest stars are intermediate mass asymptotic
giant branch (AGB) stars. These stars can contribute nearly 50% of the
integrated luminosity at near infrared and even optical wavelengths,
particularly for the younger stellar populations characteristic of
high-redshift galaxies (z1). AGB stars are also significant sources
of dust and heavy elements. Accurate modeling of AGB stars is
therefore of the utmost importance.

The primary limitation facing current models is the lack of useful
calibration data. Current models are tuned to match the properties of
the AGB population in the Magellanic Clouds, and thus have only been
calibrated in a very narrow range of sub-solar metallicities.
Preliminary observations already suggest that the models are
overestimating AGB lifetimes by factors of 2-3 at lower metallicities.
At higher (solar) metallicities, there are no appropriate observations
for calibrating the models.

We propose a WFC3/IR SNAP survey of nearby galaxies to create a large
database of AGB populations spanning the full range of metallicities
and star formation histories. Because of their intrinsically red
colors and dusty circumstellar envelopes, tracking the numbers and
bolometric fluxes of AGB stars requires the NIR observations we
propose here. The resulting observations of nearby galaxies with deep
ACS imaging offer the opportunity to obtain large (100-1000's)
complete samples of AGB stars at a single distance, in systems with
well-constrained star formation histories and metallicities.

FGS 11704

The Ages of Globular Clusters and the Population II Distance Scale

Globular clusters are the oldest objects in the universe whose age can
be accurately determined. The dominant error in globular cluster age
determinations is the uncertain Population II distance scale. We
propose to use FGS 1R to obtain parallaxes with an accuracy of 0.2
milliarcsecond for 9 main sequence stars with [Fe/H] -1.5. This will
determine the absolute magnitude of these stars with accuracies of
0.04 to 0.06mag. This data will be used to determine the distance to
24 metal-poor globular clusters using main sequence fitting. These
distances (with errors of 0.05 mag) will be used to determine the ages
of globular clusters using the luminosity of the subgiant branch as an
age indicator. This will yield absolute ages with an accuracy of 5%,
about a factor of two improvement over current estimates. Coupled with
existing parallaxes for more metal-rich stars, we will be able to
accurately determine the age for globular clusters over a wide range
of metallicities in order to study the early formation history of the
Milky Way and provide an independent estimate of the age of the
universe.

The Hipparcos database contains only 1 star with [Fe/H] -1.4 and an
absolute magnitude error less than 0.18 mag which is suitable for use
in main sequence fitting. Previous attempts at main sequence fitting
to metal-poor globular clusters have had to rely on theoretical
calibrations of the color of the main sequence. Our HST parallax
program will remove this source of possible systematic error and yield
distances to metal-poor globular clusters which are significantly more
accurate than possible with the current parallax data. The HST
parallax data will have errors which are 10 times smaller than the
current parallax data. Using the HST parallaxes, we will obtain main
sequence fitting distances to 11 globular clusters which contain over
500 RR Lyrae stars. This will allow us to calibrate the absolute
magnitude of RR Lyrae stars, a commonly used Population II distance
indicator.

COS/NUV/FUV 11698

The Structure and Dynamics of Virgo's Multi-Phase Intracluster Medium

The dynamical flows of the intracluster medium (ICM) are largely
unknown. We propose to map the spatial and kinematic distribution of
the warm ICM of the nearby Virgo cluster using the Cosmic Origins
Spectrograph. 15 sightlines at a range of impact parameters within the
virial radius of the cluster (0.2 - 1.7 Mpc) will be probed for
Lyman-alpha absorption and the data compared to blind HI, dust and
x-ray surveys to create a multi-phase map of the cluster's ICM.
Absorption line sightlines are commonly 40-100 kpc from a galaxy,
allowing the flow of baryons between galaxies and the ICM to be
assessed. The velocity distribution of the absorbers will be directly
compared to simulations and used to constrain the turbulent motions of
the ICM. This proposal will result in the first map of a cluster's
warm ICM and provide important tests for our theoretical understanding
of cluster formation and the treatment of gas cooling in cosmological
simulations.

ACS/WFC3 11669

The Origins of Short Gamma-Ray Bursts

During the past decade extraordinary progress has been made in
determining the origin of long- duration gamma-ray bursts. It has been
conclusively shown that these objects derive from the deaths of
massive stars. Nonetheless, the origin of their observational cousins,
short-duration gamma-ray bursts (SGRBs) remains a mystery. While SGRBs
are widely thought to result from the inspiral of compact binaries,
this is a conjecture. SGRBs have been found in elliptical galaxies,
Abell Clusters, star-forming dwarfs and even an edge-on spiral.
Whether they primarily result from an old population, a young
population, or rapid evolution of binaries in globular clusters
remains open.

Here we propose to employ two related sets of observations which may
dramatically advance our understanding of short bursts. The first is a
variant of a technique that we pioneered and used to great effect in
elucidating the origins of long-duration bursts. We will examine a
statistical sample of hosts and measure the degree to which SGRB
locations trace the red or blue light of their hosts, and thus old or
young stellar populations. This will allow us to study the
demographics of the SGRB population in a manner largely free of the
distance dependent selection effects which have so far bedeviled this
field. In the second line of attack we will use two targets of
opportunity to obtain extremely precise positions of up to two nearby
bursts -- one on a star-forming galaxy and the other on a elliptical.
Observation of the star-formation galaxy could link at least some
bursts directly to a young population; however, a discovery in later
images of a globular cluster at the site of the explosion in an
elliptical would provide revolutionary evidence that SGRBs are formed
from compact binaries.

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/UV/ACS/WFC 11636

First Resolved Imaging of Escaping Lyman Continuum

The emission from star-forming galaxies appears to be responsible for
reionization of the universe at z 6. However, the models that
attempt to describe the detailed impact of high-redshift galaxies on
the surrounding inter-galactic medium (IGM) are strongly dependent
upon several uncertain parameters. Perhaps the most uncertain is the
fraction of HI-ionizing photons produced by young stars that escape
into the IGM. Most attempts to measure this "escape fraction" have
produced null results. Recently, a small subset of z~3 Lyman Break
Galaxies (LBGs) has been found exhibiting large escape fractions. It
remains unclear however, what differentiates them from other LBGs.
Several models attempt to explain how such a large fraction of
ionizing continuum can escape through the HI and dust in the ISM (eg.
"chimneys" created by SNe winds, globular cluster formation, etc.),
each producing unique signatures which can be observed with resolved
imaging of the escaping Lyman continuum. To date, there are only six
LBGs with individual detections of escaping Lyman continuum at any
redshift. We propose a single deep, high resolution WFC3/UVIS image of
the ionizing continuum (F336W) and the rest-frame UV/optical
(F606W/F814W/F160W) of five of these six LBGs with large escape
fractions. These LBGs have a high surface density and large escape
fractions, and lie at the optimal redshift for Lyman continuum imaging
with UVIS filters, making our sample especially suitable for
follow-up. With these data we will discern the mechanisms responsible
for producing large escape fractions, and therefore gain insight into
the process of reionization.

STIS/CCD 11634

Probing the Collimation of Pristine Post-AGB Jets with STIS

The shaping of planetary and protoplanetary nebulae (PNe and PPNe) is
probably the most exciting yet least understood problem in the late
evolution of ~1-8 solar mass stars. An increasing number of
astronomers believe that fast jet-like winds ejected in the PPN phase
are responsible for carving out the diverse shapes in the dense
envelopes of the Asymptotic Giant Branch (AGB) stars. To date, the
properties of these post-AGB jets have not been characterized and,
indeed, their launching/collimation mechanism is still subject to
controversial debate. This is due to the lack of the direct
observations probing the spatio-kinematic structure of post-AGB winds
in the stellar vicinity (~10e16cm), which is only possible with
HST+STIS.

Recently, STIS observations have allowed us for the first time the
DIRECT study of the structure and kinematics of the elusive post-AGB
winds in one PPN, He3-1475 (Sanchez Contreras & Sahai 2001). Those
winds have been discovered through H-alpha blue-shifted absorption
features in the inner 0.3"-0.7" of the nebula. These STIS observations
have revealed an ultra-fast collimated outflow relatively unaffected
by the interaction with the AGB wind that is totally hidden in
ground-based spectroscopic observations and HST images. The discovery
of the pristine ultra-fast (~2300km/s) jet in He3-1475 is the first
observational confirmation of the presence of collimated outflows as
close as ~10e16cm from the central star. Most importantly, the
spatio-kinematic structure of the ultra-fast jet clearly rules out
hydrodynamical collimation alone and favors magnetic wind collimation.
Therefore, STIS observations provide a unique method of probing the
structure, kinematics, and collimation mechanism of the elusive
post-AGB winds. We now propose similar observations for a sample of
bipolar PPNe with ongoing post-AGB ejections in order to investigate
the frequency of jets like those in He3-1475 in other PPNe and
elucidate their nature and collimation mechanism. The observational
characterization of these winds is indispensable for understanding
this violent and important phase of post-AGB evolution.

WFC3/IR 11631

Binary Brown Dwarfs and the L/T Transition

Brown dwarfs traverse spectral types M, L and T as their atmospheric
structure evolves and they cool into oblivion. This SNAPSHOT program
will obtain WFC3-IR images of 45 nearby late-L and early-T dwarfs to
investigate the nature of the L/T transition. Recent analyses have
suggested that a substantial proportion of late-L and early-T dwarfs
are binaries, comprised of an L dwarf primary and T dwarf secondary.
WFC3-IR observations will let us quantify this suggestion by expanding
coverage to a much larger sample, and permitting comparison of the L/T
binary fraction against 'normal' ultracool dwarfs. Only eight L/T
binaries are currently known, including several that are poorly
resolved: we anticipate at least doubling the number of resolved
systems. The photometric characteristics of additional resolved
systems will be crucial to constraining theoretical models of these
late-type ultracool dwarfs. Finally, our data will also be eminently
suited to searching for extremely low luminosity companions,
potentially even reaching the Y dwarf regime.

WFC3/UVIS 11628

Globular Cluster Candidates for Hosting a Central Black Hole

We are continuing our study of the dynamical properties of globular
clusters and we propose to obtain surface brightness profiles for high
concentration clusters. Our results to date show that the distribution
of central surface brightness slopes do not conform to standard
models. This has important implications for how they form and evolve,
and suggest the possible presence of central intermediate-mass black
holes. From our previous archival proposals (AR-9542 and AR- 10315),
we find that many high concentration globular clusters do not have
flat cores or steep central cusps, instead they show weak cusps.
Numerical simulations suggest that clusters with weak cusps may harbor
intermediate-mass black holes and we have one confirmation of this
connection with omega Centauri. This cluster shows a shallow cusp in
its surface brightness profile, while kinematical measurements suggest
the presence of a black hole in its center. Our goal is to extend
these studies to a sample containing 85% of the Galactic globular
clusters with concentrations higher than 1.7 and look for objects
departing from isothermal behavior. The ACS globular cluster survey
(GO-10775) provides enough objects to have an excellent coverage of a
wide range of galactic clusters, but it contains only a couple of the
ones with high concentration. The proposed sample consists of clusters
whose light profile can only be adequately measured from space-based
imaging. This would take us close to completeness for the high
concentration cases and therefore provide a more complete list of
candidates for containing a central black hole. The dataset will also
be combined with our existing kinematic measurements and enhanced with
future kinematic studies to perform detailed dynamical modeling.

ACS/WFC/WFC3/IR 11624

Black Hole Superkicks: Lmaging the Site of a Gravitational Wave Recoil
Event

Recent numerical relativity simulations of coalescing, binary
supermassive black holes (SMBHs) predict kick velocities as large as
several thousand km/s due to anisotropic emission of gravitational
waves. We have recently discovered the best candidate to date for such
a recoiling SMBH, the quasar SDSS0927+2943. It shows an exceptional
optical emission-line spectrum with two sets of emission lines; one
set of very narrow emission lines, and a second set of broad Balmer
and broad high-ionization forbidden lines which are blueshifted by
2650 km/s relative to the narrow emission lines. This is the predicted
spectroscopic signature of a SMBH recoiling from the core of its host
galaxy, carrying with it the broad-line gas while leaving behind the
bulk of the narrow-line gas. We apply for HST imaging in two filters
for two orbits each in order to confirm the recoil model by detecting
the host galaxy of the SMBH and measuring the angular offset of the
recoiling SMBH from the host galaxy core; and determining, if
possible, the morphology of the host galaxy in order to constrain its
merger history. Confirmation of the SMBH ejection model for
SDSSJ0927+2943 with HST will show decisively that kicks large enough
to remove SMBHs completely from their host galaxies do occur, a result
that would have profound implications for models of SMBH evolution and
galaxy assembly and for numerical relativity.

WFC3/UV 11602

High-resolution imaging of three new UV-bright lensed arcs

We have identified and spectroscopically confirmed three new strongly
lensed, UV-bright star-forming galaxies at z ~ 2 that are similar to
the well-studied gravitationally lensed Lyman Break Galaxy (LBG)
MS1512-cB58, and are of comparable brightness to the ''8 O'Clock Arc''
(Allam et al. 2007) and ''Clone'' systems (Lin et al. 2008). The 8
O'Clock Arc and Clone have already been awarded 20 orbits for deep
WFPC2 and NICMOS imaging in five bands (HST cycle 16, Program 11167,
PI: Allam). Adding these three recently discovered objects thus
completes a unique set of the brightest known strongly lensed galaxies
at z ~ 2, with magnitudes of r~20-21, and they provide a new window
into the detailed study of the properties of high redshift galaxies.
We propose 21 orbits for deep WFC3 imaging in five bands (F475W,
F606W, F814W, F110W, and F160W) in order to construct detailed lensing
models, to probe the mass and light profiles of the lensing galaxies
and their environments, and to constrain the spectral energy
distributions, star formation histories, and morphologies of the
lensed galaxies.

STIS/CCD/MA2 11568

A SNAPSHOT Survey of the Local Interstellar Medium: New NUV
Observations of Stars with Archived FUV Observations

We propose to obtain high-resolution STIS E230H SNAP observations of
MgII and FeII interstellar absorption lines toward stars within 100
parsecs that already have moderate or high-resolution far-UV (FUV),
900-1700 A, observations available in the MAST Archive. Fundamental
properties, such as temperature, turbulence, ionization, abundances,
and depletions of gas in the local interstellar medium (LISM) can be
measured by coupling such observations. Due to the wide spectral range
of STIS, observations to study nearby stars also contain important
data about the LISM embedded within their spectra. However, unlocking
this information from the intrinsically broad and often saturated FUV
absorption lines of low-mass ions, (DI, CII, NI, OI), requires first
understanding the kinematic structure of the gas along the line of
sight. This can be achieved with high resolution spectra of high-mass
ions, (FeII, MgII), which have narrow absorption lines, and can
resolve each individual velocity component (interstellar cloud). By
obtaining short (~10 minute) E230H observations of FeII and MgII, for
stars that already have moderate or high- resolution FUV spectra, we
can increase the sample of LISM measurements, and thereby expand our
knowledge of the physical properties of the gas in our galactic
neighborhood. STIS is the only instrument capable of obtaining the
required high resolution data now or in the foreseeable future.

 




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