HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5081
PERIOD
COVERED: 5am April 22 - 5am April 23, 2010 (DOY 112/09:00z-113/09:00z)
OBSERVATIONS
SCHEDULED
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.
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.
COS/FUV
11687
SNAPing
Coronal Iron
This
is a Snapshot Survey to explore two forbidden lines of highly
ionized
iron in late-type coronal sources. Fe XII 1349 (T~ 2 MK) and Fe
XXI
1354 (T~ 10 MK) -- well known to Solar Physics -- have been detected
in
about a dozen cool stars, mainly with HST/STIS. The UV coronal
forbidden
lines are important because they can be observed with velocity
resolution
of better than 15 km/s, whereas even the state-of-the-art
X-ray
spectrometers on Chandra can manage only 300 km/s in the kilovolt
band
where lines of highly ionized iron more commonly are found. The
kinematic
properties of hot coronal plasmas, which are of great interest
to
theorists and modelers, thus only are accessible in the UV at
present.
The bad news is that the UV coronal forbidden lines are faint,
and
were captured only in very deep observations with STIS. The good
news
is that 3rd-generation Cosmic Origins Spectrograph, slated for
installation
in HST by SM4, in a mere 25 minute exposure with its G130M
mode
can duplicate the sensitivity of a landmark 25-orbit STIS E140M
observation
of AD Leo, easily the deepest such exposure of a late-type
star
so far. Our goal is to build up understanding of the properties of
Fe
XII and Fe XXI in additional objects beyond the current limited
sample:
how the lineshapes depend on activity, whether large scale
velocity
shifts can be detected, and whether the dynamical content of
the
lines can be inverted to map the spatial morphology of the stellar
corona
(as in "Doppler Imaging''). In other words, we want to bring to
bear
in the coronal venue all the powerful tricks of spectroscopic
remote
sensing, well in advance of the time that this will be possible
exploiting
the corona's native X-ray radiation. The 1290-1430 band
captured
by side A of G130M also contains a wide range of key plasma
diagnostics
that form at temperatures from below 10, 000 K (neutral
lines
of CNO), to above 200, 000 K (semi-permitted O V 1371), including
the
important bright multiplets of C II at 1335 and Si IV at 1400;
yielding
a diagnostic gold mine for the subcoronal atmosphere. Because
of
the broad value of the SNAP spectra, beyond the coronal iron project,
we
waive the normal proprietary rights.
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.
STIS/CC
11845
CCD
Dark Monitor Part 2
Monitor
the darks for the STIS CCD.
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.
WFC3/ACS/IR
11600
Star
Formation, Extinction, and Metallicity at 0.7<z<1.5: H-Alpha Fluxes
and
Sizes from a Grism Survey of GOODS-N
The
global star formation rate (SFR) is ~10x higher at z=1 than today.
This
could be due to drastically elevated SFR in some fraction of
galaxies,
such as mergers with central bursts, or a higher SFR across
the
board. Either means that the conditions in z=1 star forming galaxies
could
be quite different from local objects. The next step beyond
measuring
the global SFR is to determine the dependence of SFR,
obscuration,
metallicity, and size of the star-forming region on galaxy
mass
and redshift. However, SFR indicators at z=1 typically apply local
calibrations
for UV, [O II] and far-IR, and do not agree with each other
on
a galaxy-by-galaxy basis. Extinction, metallicity, and dust
properties
cause uncontrolled offsets in SFR calibrations. The great
missing
link is Balmer H-alpha, the most sensitive probe of SFR. We
propose
a slitless WFC3/G141 IR grism survey of GOODS-N, at 2
orbits/pointing.
It will detect Ha+[N II] emission from 0.7<z<1.5, to
L(Ha)
= 1.7 x 10^41 erg/sec at z=1, measuring H-alpha fluxes and sizes
for
> 600 galaxies, and a small number of higher-redshift emitters. This
will
produce: an emission-line redshift survey unbiased by magnitude and
color
selection; star formation rates as a function of galaxy
properties,
e.g. stellar mass and morphology/mergers measured by ACS;
comparisons
of SFRs from H-alpha to UV and far-IR indicators;
calibrations
of line ratios of H-alpha to important nebular lines such
as
[O II] and H-beta, measuring variations in metallicity and extinction
and
their effect on SFR estimates; and the first measurement of scale
lengths
of the H-alpha emitting, star- forming region in a large sample
of
z~1 sources.
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 (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
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.
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).
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/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/UVIS/IR
11662
Improving
the Radius-Luminosity Relationship for Broad-Lined AGNs with a
New
Reverberation Sample
The
radius-luminosity (R-L) relationship is currently the fundamental
basis
for all techniques used to estimate black hole masses in AGNs, in
both
the nearby and distant universe. However, the current R-L
relationship
is based on 34 objects that cover a limited range in black
hole
mass and luminosity. To improve our understanding of black hole
growth
and evolution, the R-L relationship must be extended to cover a
broader
range of black hole masses using the technique known as
reverberation
mapping. To this end, we have been awarded an
unprecedented
64 nights on the Lick Observatory 3-m telescope between
March
24 and May 31, 2008, to spectroscopically monitor 12 AGNs in order
to
measure their black hole masses. To properly determine the
luminosities
of these 12 AGNs, we must correct them for their
host-galaxy
starlight contributions using high-resolution images.
Previous
work by Bentz et al. (2006) has shown that the starlight
correction
to AGN luminosity measurements is an essential component to
interpreting
the R-L relationship. The correction will be substantial
for
each of the 12 sources we will monitor, as the AGNs are relatively
faint
and embedded in nearby, bright galaxies. Starlight corrections are
not
possible with ground-based images, as the PSF and bulge
contributions
become indistinguishable under typical seeing conditions,
and
adaptive optics are not yet operational in the spectral range where
the
corrections are needed. In addition, spectral decompositions are
very
model-dependent and are limited by the degree of accuracy to which
we
understand emission processes and stellar populations in galaxies.
Without
correcting for starlight, we will be unable to apply the results
of
our Spring 2008 campaign to the body of knowledge from previous
reverberation
mapping work. Therefore, we propose to obtain high
resolution,
high dynamic range images of the host galaxies of the 12
AGNs
in our ground-based monitoring sample, as well as one white dwarf
which
will be used as a PSF model.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
(None)
COMPLETED
OPS REQUEST:
18843-2
- Installation of FSW Acq Logic B @ 112/1648z
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSAcq
8
8
FGS
REAcq
6
6
OBAD
with Maneuver 4
4
SIGNIFICANT
EVENTS:
FLASH:
At
112/16:46z Acq Logic Version B was successfully installed
on-orbit.
The Guide Star Acquisition at 112/21:10z was successfully
performed
using the new acquisition logic.