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)
OBSERVATION=
S
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
observation=
s
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=3D1,
and
1x1 at gain =3D 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)=3D 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-ba=
sed,
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
spectroscop=
ic
and photometric constraints, the only viable =
explanation
for
the main sequence splitting appears to be Helium enrichment, up =
to
an
astonishingly high Y=3D0.4. 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-format=
ion,
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
interpretat=
ion
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,
particularl=
y
for the younger stellar populations characteristic =
of
high-redshi=
ft
galaxies (z>1). 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
overestimat=
ing
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
determinati=
ons
is the uncertain Population II distance scale. We =
propose
to
use FGS 1R to obtain parallaxes with an accuracy of =
0.2
milliarcsec=
ond
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
metalliciti=
es
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
calibration=
s
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
Spectrograp=
h.
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
distributio=
n
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
conclusivel=
y
shown that these objects derive from the deaths of =
massive
stars.
Nonetheless, the origin of their observational =
cousins,
short-durat=
ion
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
dramaticall=
y
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-format=
ion
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
revolutiona=
ry
evidence that SGRBs are formed from compact binaries. =
WFC3/UVIS/I=
R
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
composition=
al
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
gravitation=
al
influence of the early giant planets and an attempt =
is
made
to reproduce the current observed populations. With =
little
composition=
al
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
capabilitie=
s
of WFC3 to perform the first ever large-scale
dynamical-c=
ompositional
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
understandi=
ng
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
reionizatio=
n
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/c=
ollimation
mechanism is still subject to controversial
debate.
This is due to the lack of the direct observations probing =
the
spatio-kine=
matic
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
spectroscop=
ic
observations and HST images. The discovery of the =
pristine
ultra-fast
(~2300km/s) jet in He3-1475 is the first =
observational
confirmatio=
n
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
indispensab=
le
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
observation=
s
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
concentrati=
on
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
completenes=
s
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
measurement=
s
and enhanced with future kinematic studies to =
perform
detailed
dynamical modeling.
ACS/WFC/WFC=
3/IR
11624
Black
Hole Superkicks: Lmaging the Site of a Gravitational Wave =
Recoil
Event
Recent
numerical relativity simulations of coalescing, =
binary
supermassiv=
e
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
spectroscop=
ic
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-resolu=
tion
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-studie=
d
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
environment=
s,
and to constrain the spectral energy distributions, =
star
formation
histories, and morphologies of the lensed galaxies. =
STIS/CCD/MA=
2
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
understandi=
ng
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.