HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #4963
PERIOD
COVERED: 5am October 30 - 5am November 2, 2009 (DOY 303/09:00z-306/10:00z)
OBSERVATIONS
SCHEDULED
COS/FUV
11997
FUV
Internal/External Wavelength Scale Monitor
This
program monitors the offsets between the wavelength scale set by
the
internal wavecal versus that defined by absorption lines in external
targets.
This is accomplished by observing two external targets in the
SMC:
SK191 with G130M and G160M and Cl* NGC 330 ROB B37 with G140L
(SK191
is too bright to be observed with G140L). The cenwaves observed
in
this program are a subset of the ones used during Cycle 17. Observing
all
cenwaves would require a considerably larger number of orbits.
Constraints
on scheduling of each target are placed so that each target
is
observed once every ~2-3 months. Observing the two targets every
month
would also require a considerably larger number of orbits.
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/UV
11923
UVIS
Filter Wedge Check
The
position of each UVIS filter will be checked to verify that the
filters
meet the CEI (Contract End Item) specification for image
displacement.
We will observe NGC 1850 with all full-frame UVIS filters
using
a subarray (UVIS1-C512A) without moving the telescope, as well as
the
quad filters with a 512x512 specifically designed subarray. We will
also
acquire one grism exposure. The relative displacement of the stars
in
each image will be measured from one filter to the next.
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
11907
UVIS
Cycle 17 Contamination Monitor
The
UV throughput of WFC3 during Cycle 17 is monitored via weekly
standard
star observations in a subset of key filters covering 200-600nm
and
F606W, F814W as controls on the red end. The data will provide a
measure
of throughput levels as a function of time and wavelength,
allowing
for detection of the presence of possible contaminants.
WFC3/UVIS
11905
WFC3
UVIS CCD Daily Monitor
The
behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame,
four-amp bias and dark frames. A smaller set of 2Kx4K
subarray
biases are acquired at less frequent intervals throughout the
cycle
to support subarray science observations. The internals from this
proposal,
along with those from the anneal procedure (Proposal 11909),
will
be used to generate the necessary superbias and superdark reference
files
for the calibration pipeline (CDBS).
ACS/WFC3
11887
CCD
Stability Monitor
This
program will verify that the low frequency flat fielding, the
photometry,
and the geometric distortion are stable in time and across
the
field of view of the CCD arrays. A moderately crowded stellar field
in
the cluster 47 Tuc is observed with the ACS (at the cluster core) and
WFC3
(6 arcmin West of the cluster core) using the full suite of broad
and
narrow band imaging filters. The positions and magnitudes of objects
will
be used to monitor local and large scale variations in the plate
scale
and the sensitivity of the detectors and to derive an independent
measure
of the detector CTE. The UV sensitivity for the SBC and ACS will
be
addressed in the UV contamination monitor program (11886, PI=Smith).
One
additional orbit will be obtained at the beginning of the cycle will
allow
a verification of the CCD gain ratios for WFC3 using gain 2.0,
1.4,
1.0, 0.5 and for ACS using gain 4.0 and 2.0. In addition, one
subarray
exposure with the WFC3 will allow a verification that
photometry
obtained in full-frame and in sub-array modes are repeatable
to
better than 1%. This test is important for the ACS Photometric
Cross-Calibration
program (11889, PI=Bohlin) which uses sub-array
exposures.
ACS/WFC3
11879
CCD
Daily Monitor (Part 1)
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 352 orbits (22 weeks) from 31 August 2009 to 31 January
2010.
STIS/MA
11863
STIS
MAMA Fold Distribution
The
performance of MAMA microchannel plates can be monitored using a
MAMA
fold analysis procedure. The fold analysis provides a measurement
of
the distribution of charge cloud sizes incident upon the anode giving
some
measure of changes in the pulse-height distribution of the MCP and,
therefore,
MCP gain. This proposal executes the same steps as the STIS
MAMA
Fold Analysis (10035) during Cycle 12.
STIS/CCD
11846
CCD
Bias Monitor-Part 1
The
purpose of this proposal is to monitor the bias in the 1x1, 1x2,
2x1,
and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up
high-S/N
superbiases and track the evolution of hot columns.
STIS/CCD
11844
CCD
Dark Monitor Part 1
The
purpose of this proposal is to monitor the darks for the STIS CCD.
FGS
11788
The
Architecture of Exoplanetary Systems
Are
all planetary systems coplanar? Concordance cosmogony makes that
prediction.
It is, however, a prediction of extrasolar planetary system
architecture
as yet untested by direct observation for main sequence
stars
other than the Sun. To provide such a test, we propose to carry
out
FGS astrometric studies on four stars hosting seven companions. Our
understanding
of the planet formation process will grow as we match not
only
system architecture, but formed planet mass and true distance from
the
primary with host star characteristics for a wide variety of host
stars
and exoplanet masses.
We
propose that a series of FGS astrometric observations with
demonstrated
1 millisecond of arc per-observation precision can
establish
the degree of coplanarity and component true masses for four
extrasolar
systems: HD 202206 (brown dwarf+planet); HD 128311
(planet+planet),
HD 160691 = mu Arae (planet+planet), and HD 222404AB =
gamma
Cephei (planet+star). In each case the companion is identified as
such
by assuming that the minimum mass is the actual mass. For the last
target,
a known stellar binary system, the companion orbit is stable
only
if coplanar with the AB binary orbit.
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.
STIS/CCD
11721
Verifying
the Utility of Type Ia Supernovae as Cosmological Probes:
Evolution
and Dispersion in the Ultraviolet Spectra
The
study of distant type Ia supernova (SNe Ia) offers the most
practical
and immediate discriminator between popular models of dark
energy.
Yet fundamental questions remain over possible
redshift-dependent
trends in their observed and intrinsic properties.
High-quality
Keck spectroscopy of a representative sample of 36
intermediate
redshift SNe Ia has revealed a surprising, and unexplained,
diversity
in their rest-frame UV fluxes. One possible explanation is
hitherto
undiscovered variations in the progenitor metallicity.
Unfortunately,
this result cannot be compared to local UV data as only
two
representative SNe Ia have been studied near maximum light. Taking
advantage
of two new `rolling searches' and the restoration of STIS, we
propose
a non-disruptive TOO campaign to create an equivalent comparison
local
sample. This will allow us to address possible evolution in the
mean
UV spectrum and its diversity, an essential precursor to the study
of
SNe beyond z~1.
ACS/WFC
11689
Direct
Observations of Dark Matter from a Second Bullet: The Spectacular
Abell
2744
Vigorous
cluster mergers provide a unique opportunity to directly "see"
dark
matter and to probe its properties through the analysis of the
segregation
of the baryonic and non-baryonic components. This is
accomplished
through detailed comparison of the mass distributions as
traced
by X-ray emitting gas and by gravitational lensing. This
condition
is rare and so far only one cluster has met these
requirements,
the so-called "bullet" cluster, producing exciting results
and
placing constraints to the properties of dark matter. These
constraints
have a broad impact on models for formation of structure and
on
galaxy evolution. This multi-wavelength analysis has the potential
confront
alternative gravity models such as MOND. Therefore, it is
crucial
to find new bullet clusters to corroborate and improve
previous
measurements. This is the most direct way to constrain dark
matter
properties and A2744 is ideal for corroborating this study since
it
maximizes all the requirements for this analysis. Here, we propose to
carry
out such analysis through combined ACS and Chandra observations of
the
cluster merger Abell 2744.
WFC3/UV/ACS/WFC
11688
Exploring
the Bottom End of the White Dwarf Cooling Sequence in the Open
Cluster
NGC6819
The
recent discovery by our group of an unexpectedly bright end of the
white-dwarf
(WD) luminosity function (LF) of the metal-rich, old open
cluster
NGC 6791 casts serious doubts on our understanding of the
physical
process which rules the formation and the cooling of WDs. It is
clear
at this point that the theory badly needs more observations. Here
we
propose WFC3/UVIS and ACS/WFC HST observations reaching the bottom
end
of the WD LF, for the first time in a solar-metallicity,
2.5-Gyr-old,
populous open cluster: NGC 6819.
ACS/WFC3
11670
The
Host Environments of Type Ia Supernovae in the SDSS Survey
The
Sloan Digital Sky Survey Supernova Survey has discovered nearly 500
type
Ia supernovae and created a large, unique, and uniform sample of
these
cosmological tools. As part of a comprehensive study of the
supernova
hosts, we propose to obtain Hubble ACS images of a large
fraction
of these galaxies. Integrated colors and spectra will be
measured
from the ground, but we require high-resolution HST imaging to
provide
accurate morphologies and color information at the site of the
explosion.
This information is essential in determining the systematic
effects
of population age on type Ia supernova luminosities and
improving
their reliability in measuring dark energy. Recent studies
suggest
two populations of type Ia supernovae: a class that explodes
promptly
after star-formation and one that is delayed by billions of
years.
Measuring the star-formation rate at the site of the supernova
from
colors in the HST images may be the best way to differentiate
between
these classes.
WFC3/IR
11666
Chilly
Pairs: A Search for the Latest-type Brown Dwarf Binaries and the
Prototype
Y Dwarf
We
propose to use HST/NICMOS to image a sample of 27 of the nearest (<
20
pc) and lowest luminosity T-type brown dwarfs in order to identify
and
characterize new very low mass binary systems. Only 3 late-type T
dwarf
binaries have been found to date, despite that fact that these
systems
are critical benchmarks for evolutionary and atmospheric models
at
the lowest masses. They are also the most likely systems to harbor Y
dwarf
companions, an as yet unpopulated putative class of very cold (T <
600
K) brown dwarfs. Our proposed program will more than double the
number
of T5-T9 dwarfs imaged at high resolution, with an anticipated
yield
of ~5 new binaries with initial characterization of component
spectral
types. We will be able to probe separations sufficient to
identify
systems suitable for astrometric orbit and dynamical mass
measurements.
We also expect one of our discoveries to contain the first
Y-type
brown dwarf. Our proposed program complements and augments
ongoing
ground-based adaptive optics surveys and provides pathway
science
for JWST.
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.
COS/FUV
11625
Beyond
the Classical Paradigm of Stellar Winds: Investigating Clumping,
Rotation
and the Weak Wind Problem in SMC O Stars
SMC
O stars provide an unrivaled opportunity to probe star formation,
evolution,
and the feedback of massive stars in an environment similar
to
the epoch of the peak in star formation history. Two recent
breakthroughs
in the study of hot, massive stars have important
consequences
for understanding the chemical enrichment and buildup of
stellar
mass in the Universe. The first is the realization that rotation
plays
a major role in influencing the evolution of massive stars and
their
feedback on the surrounding environment. The second is a drastic
downward
revision of the mass loss rates of massive stars coming from an
improved
description of their winds. STIS spectroscopy of SMC O stars
combined
with state-of-the-art NLTE analyses has shed new light on these
two
topics. A majority of SMC O stars reveal CNO-cycle processed
material
brought at their surface by rotational mixing. Secondly, the
FUV
wind lines of early O stars provide strong indications of the
clumped
nature of their wind. Moreover, we first drew attention to some
late-O
dwarfs showing extremely weak wind signatures. Consequently, we
have
derived mass loss rates from STIS spectroscopy that are
significantly
lower than the current theoretical predictions used in
evolutionary
models. Because of the limited size of the current sample
(and
some clear bias toward stars with sharp-lined spectra), these
results
must however be viewed as tentative. Thanks to the high
efficiency
of COS in the FUV range, we propose now to obtain
high-resolution
FUV spectra with COS of a larger sample of SMC O stars
to
study systematically rotation and wind properties of massive stars at
low
metallicity. The analysis of the FUV wind lines will be based on our
2D
extension of CMFGEN to model axi-symmetric rotating winds.
WFC3/UVIS
11594
A
WFC3 Grism Survey for Lyman Limit Absorption at z=2
We
propose to conduct a spectroscopic survey of Lyman limit absorbers at
redshifts
1.8 < z < 2.5, using WFC3 and the G280 grism. This proposal
intends
to complete an approved Cycle 15 SNAP program (10878), which was
cut
short due to the ACS failure. We have selected 64 quasars at 2.3 < z
<
2.6 from the Sloan Digital Sky Survey Spectroscopic Quasar Sample, for
which
no BAL signature is found at the QSO redshift and no strong metal
absorption
lines are present at z > 2.3 along the lines of sight. The
survey
has three main observational goals. First, we will determine the
redshift
frequency dn/dz of the LLS over the column density range 16.0 <
log(NHI)
< 20.3 cm^-2. Second, we will measure the column density
frequency
distribution f(N) for the partial Lyman limit systems (PLLS)
over
the column density range 16.0 < log(NHI) < 17.5 cm^-2. Third, we
will
identify those sightlines which could provide a measurement of the
primordial
D/H ratio. By carrying out this survey, we can also help
place
meaningful constraints on two key quantities of cosmological
relevance.
First, we will estimate the amount of metals in the LLS using
the
f(N), and ground based observations of metal line transitions.
Second,
by determining f(N) of the PLLS, we can constrain the amplitude
of
the ionizing UV background at z~2 to a greater precision. This survey
is
ideal for a snapshot observing program, because the on-object
integration
times are all well below 30 minutes, and follow-up
observations
from the ground require minimal telescope time due to the
QSO
sample being bright.
WFC3/UV
11589
Hypervelocity
Stars as Unique Probes of the Galactic Center and Outer
Halo
We
propose to obtain high-resolution images of 11 new hypervelocity
stars
in the Galactic halo in order to establish the first-epoch
astrometric
frame, as a part of a long-term program to measure precise
proper
motions in an absolute inertial frame. The origin of these
recently
discovered stars with extremely large positive radial
velocities,
in excess of the escape speed from the Galaxy, is consistent
only
with being ejected from the deep potential well of the massive
black
hole at the Galactic center. Reconstructing the full
three-dimensional
space motion of the hypervelocity stars, through
astrometric
proper motions, provides a unique opportunity to measure the
shape
and orientation of the triaxial dark matter halo. The
hypervelocity
stars allow determination of the Galactic potential out to
120
kpc, independently of and at larger distances than is afforded by
tidal
streams of satellite galaxies such as the Sagittarius dSph galaxy.
Proper
motions of the full set of hypervelocity stars will provide
unique
constraints on massive star formation in the environment of the
Galactic
center and on the history of stellar ejection by the
supermassive
black hole. We request one orbit with WFC3 for each of the
11
hypervelocity stars to establish their current positions relative to
background
galaxies. We request a repeated observation of these stars in
Cycle
19, which will conclusively measure the astrometric proper
motions.
STIS/CCD
11572
Charaterizing
Atmospheric Sodium in the Transiting hot-Jupiter HD189733b
We
propose STIS transit observations of the exoplanet HD189733b with the
goal
of measuring atmospheric atomic sodium. Our strategy is to repeat
the
observing meathods used for HD209458b, which resulted in a
successful
exoplanetary atmospheric sodium detection. Initial
ground-based
measurements suggest that the sodium signature on HD189733
could
be up to three times larger than HD209458b, making a robust 8?
detection
possible within a 12 orbit program observing three transits.
Transit
transmission spectra resulting from space-based measurements
have
the advantage of retaining absolute transit depths when features
are
measured, which will make it possible to provide an observational
link
between sodium and atmospheric haze detected with ACS. Such a link
can
break modeling degeneracies and providing stringent constraints on
the
overall atmospheric properties, making such atmospheric information
as
abundances and the temperature-pressure-altitude relation known. A
successful
measurement will also allow for comparative atmospheric
exoplanetology,
as an atmospheric feature will be measured with the same
instrument
in two separate planets.
STIS/CCD
11567
Boron
Abundances in Rapidly Rotating Early-B Stars
Models
of rotation in early-B stars predict that rotationally driven
mixing
should deplete surface boron abundances during the main-sequence
lifetime
of many stars. However, recent work has shown that many boron
depleted
stars are intrinsically slow rotators for which models predict
no
depletion should have occurred, while observations of nitrogen in
some
more rapidly rotating stars show less mixing than the models
predict.
Boron can provide unique information on the earliest stages of
mixing
in B stars, but previous surveys have been biased towards narrow-
lined
stars because of the difficulty in measuring boron abundances in
rapidly
rotating stars. The two targets observed as part of our Cycle 13
SNAP
program 10175, just before STIS failed, demonstrate that it is
possible
to make useful boron abundance measurements for early-B stars
with
Vsin(i) above 100 km/s. We propose to extend that survey to a large
enough
sample of stars to allow statistically significant tests of
models
of rotational mixing in early-B stars.
WFC3/UVIS
11565
A
Search for Astrometric Companions to Very Low-Mass, Population II
Stars
We
propose to carry out a Snapshot search for astrometric companions in
a
subsample of very low-mass, halo subdwarfs identified within 120
parsecs
of the Sun. These ultra-cool M subdwarfs are local
representatives
of the lowest-mass H burning objects from the Galactic
Population
II. The expected 3-4 astrometric doubles that will be
discovered
will be invaluable in that they will be the first systems
from
which gravitational masses of metal-poor stars at the bottom of the
main
sequence can be directly measured.
NIC2/WFC3/IR
11548
Infrared
Imaging of Protostars in the Orion A Cloud: The Role of
Environment
in Star Formation
We
propose NICMOS and WFC3/IR observations of a sample of 252 protostars
identified
in the Orion A cloud with the Spitzer Space Telescope. These
observations
will image the scattered light escaping the protostellar
envelopes,
providing information on the shapes of outflow cavities, the
inclinations
of the protostars, and the overall morphologies of the
envelopes.
In addition, we ask for Spitzer time to obtain 55-95 micron
spectra
of 75 of the protostars. Combining these new data with existing
3.6
to 70 micron photometry and forthcoming 5-40 micron spectra measured
with
the Spitzer Space Telescope, we will determine the physical
properties
of the protostars such as envelope density, luminosity,
infall
rate, and outflow cavity opening angle. By examining how these
properties
vary with stellar density (i.e. clusters vs. groups vs.
isolation)
and the properties of the surrounding molecular cloud; we can
directly
measure how the surrounding environment influences protostellar
evolution,
and consequently, the formation of stars and planetary
systems.
Ultimately, this data will guide the development of a theory of
protostellar
evolution.
COS/FUV
11524
COS-GTO:
WARM AND HOT ISM IN AND NEAR THE MILKY WAY
COS
G130M and G160M 20, 000 resolution observations will be obtained for
10
AGNs situated beyond Milky Way high velocity clouds. For all objects
good
O VI line profile observations exist from FUSE and high velocity O
VI
is detected. The COS observations will be used to obtain high quality
absorption
line profiles (S/N ~ 30 to 40) for C IV, Si IV and N V in the
low
and high velocity gas toward each AGN. The high ionization profiles
of
O VI (from FUSE), N V, C IV, and Si IV will be compared to low
ionization
profiles (O I, S II, Si II, Fe II, etc.) in order to evaluate
the
physical conditions and origins of the highly ionized gas in and
near
the Milky Way at low and high velocity. The HVCs include Complex C
(four
lines of sight), Complex A, WD, WB, and several negative velocity
O
VI HVCs. Other studies to be undertaken with this data set include
studies
of the physical conditions and abundances in the cool and warm
HVC
gas and studies of the physical conditions in low redshift IGM
systems
detected along the 10 lines of sight.
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?
WFC3/IR
11208
The
Co-Evolution of Spheroids and Black Holes in the Last Six Billion
Years
The
masses of giant black holes are correlated with the luminosities,
masses,
and velocity dispersions of the bulges of their host galaxies.
This
empirical correlation of phenomena on widely different scales (from
pcs
to kpcs) suggests that the formation and evolution of galaxies and
central
black holes are closely linked. In Cycle 13, we have started a
campaign
to map directly the co-evolution of spheroids and black-holes
by
measuring in observationally favorable redshift windows the empirical
correlations
connecting their properties. By focusing on Seyfert 1s,
where
the nucleus and the stars contribute comparable fractions of total
light,
black hole mass and bulge dispersion are obtained from Keck
spectroscopy.
HST is required for accurate measurement of the
non-stellar
AGN continuum, the morphology of the galaxy, and the
structural
parameters of the bulge. The results at z=0.36 indicate a
surprisingly
fast evolution of bulges in the past 4 Gyrs (significant at
the
95%CL), in the sense that bulges were significantly smaller for a
given
black hole mass. Also, the large fraction of mergers and disturbed
galaxies
(4+2 out of 20) identifies gas-rich mergers as the mechanisms
responsible
for bulge-growth. Going to higher redshift - where
evolutionary
trends should be stronger - is needed to confirm these
tantalizing
results. We propose therefore to push our investigation to
the
next suitable redshift window z=0.57 (lookback-time 6 Gyrs). Fifteen
objects
are the minimum number required to map the evolution of the
empirical
correlations between bulge properties and black-hole mass, and
to
achieve a conclusive detection of evolution (>99%CL).
NIC1
11205
The
Effects of Multiplicity on the Evolution of Young Stellar Objects: A
NICMOS
Imaging Study
We
propose to use NICMOS to investigate the multiplicity of young
stellar
objects (YSOs) in the Orion B molecular cloud. Previous
observations
with the Spitzer Space Telescope have revealed a remarkable
star
forming filament near the NGC 2068 reflection nebula. The
population
of YSOs associated with the filament exhibit a surprisingly
wide
range of circumstellar evolutionary states, from deeply embedded
protostars
to T Tauri accretion disks. Many of the circumstellar disks
themselves
show evidence for significant dust evolution, including grain
growth
and settling and cleared inner holes, apparently in spite of the
very
young age of these stars. We will estimate the binary fraction of a
representative
sample of objects in these various stages of evolution in
order
to test whether companions may play a significant role in that
evolution.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12061
- GSAcq(1,2,1) scheduled at 304/23:27:17 resulted in fine lock backup (1,0,1).
Observations possibly affected: WFC3 138 - 142 Proposal ID#11548,
STIS 67 Proposal ID#11844, STIS 68-70 Proposal ID#11846,
ACS 119 and 120 Proposal ID#11879
12062
- GSAcq(1,2,1) scheduled at 305/19:04:37z failed due to search
radius limits exceeded on both FGS1 and FGS2.
Observations affected: ACS 127-138, proposal ID#11887.
For
Day 295 and 296
12059
- GSAcq(2,1,2) required two attempts to achieve CT-DV @ 295/13:41:55
12060
- GSAcq(1,2,1) Lost Lock @ 296/17:18:55
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSAcq
32
31
FGS
REAcq
22
22
OBAD
with Maneuver
15
15
LOSS
of
LOCK
SIGNIFICANT
EVENTS: (None)