HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4796
PERIOD COVERED: 5am February 20 - 5am February 23, 2009
(DOY
051/1000z-054/1000z)
OBSERVATIONS SCHEDULED
WFPC2 11991
Constraining the Late Time Lightcurve and Energy of GRB
090102
We propose to conduct a series of late time observations
of the
lightcurve of the bright gamma-ray burst GRB 090102.
Declared a burst of
interest by the Swift team, and with excellent broadband
data covering
the prompt emission (Swift and Fermi) and afterglow
(Swift, TAROT, NOT,
WHT, and several more), GRB 090102 offers a rare
opportunity to probe
the physics and energetics of GRBs. Its high energy budget
(>2e53 ergs
for isotropic emission) stretches plausible progenitor
models, and as
yet the signatures of jet-like emission have not been
observed. Our late
time observations will search for steepening of the
afterglow due to
lateral expansion of the jet. This will enable us, in
tandem with the
data already secured, to determine its total energy
budget, and compare
this to expectations for different progenitors models. HST
is vital to
this endeavour since it can reach depths essentially
unattainable to
ground based technology, while its invariant PSF will
allow us to
accurately remove underlying host contamination.
Ultimately, the range
and quality of data secured for this burst will enable us
to accurately
reconstruct the parameters of the explosion, and shed
greater light on
the physical processes which under lie the production of
GRBs.
WFPC2 11986
Completing HST's Local Volume Legacy
Nearby galaxies offer one of the few laboratories within
which stellar
populations can be tied to multi-wavelength observations.
They are thus
essential for calibrating and interpreting key
astrophysical
observables, such as broad-band luminosities, durations
and energy input
from starbursts, and timescales of UV, H-alpha, and FIR
emission. The
study of stellar populations in nearby galaxies requires
high-resolution
observations with HST, but HST's legacy for this limited
set of galaxies
remains incomplete.
As a first attempt to establish this legacy, The ACS
Nearby Galaxy
Survey Treasury (ANGST) began observations in late 2006.
ANGST was
designed to carry out a uniform multi-color survey of a
volume-limited
sample of ~70 nearby galaxies that could be used for
systematic studies
of resolved stellar populations. The resulting data
provide nuanced
constraints on the processes which govern star formation
and galaxy
evolution, for a well-defined population of galaxies. All
photometry for
the survey has been publicly released.
However, the failure of ACS 4.5 months after ANGST began
taking data led
to a drastic reduction in the planned survey. The loss is
two-fold.
First, the goals of completeness and uniformity were
greatly
compromised, impacting global comparison studies. Second,
the variety of
observed star formation histories was reduced. Given that
we have never
found two galaxies with identical star formation
histories, and fully
sampling the population allows us to catch those few
systems whose star
formation rates and metallicities place the strongest
constraints on key
astrophysical processes.
Here we propose WFPC2 observations of all remaining
galaxies within the
Local Volume (D<3.5Mpc) for which current HST
observations are
insufficient for meaningful stellar population studies. We
will use
these observations for research on the star formation
histories of
individual galaxies and the Local Volume, detailed
calibrations of star
formation rate indicators, and the durations of
starbursts. We will also
make them publicly available through the ANGST archive to
support future
research. The proposed observations will finally complete
a lasting
legacy of HST
WFPC2 11978
Luminous and Dark Matter in Disk Galaxies from Strong
Lensing and
Stellar Kinematics
The formation of realistic disk galaxies within the LCDM
paradigm is
still an unsolved problem. Theory is only now beginning to
make
predictions for how dark matter halos respond to galaxy
formation and
for the properties of disk galaxies. Measuring the density
profiles of
dark matter halos on galaxy scales is therefore a strong
test for the
standard paradigm of galaxy formation, offering great
potential for
discovery. However, from an observational point of view,
the degeneracy
between the stellar and dark matter contributions to
galaxy rotation
curves remains a major road block. Strong gravitational
lensing, when
coupled to spatially-resolved kinematics and stellar
population models,
can solve this long-standing problem. Unfortunately, this
joint
methodology could not be exploited so far due to the
paucity of known
edge-on spiral lenses. Exploiting the full SDSS-DR7
archive we have
identified a new sample of exactly these systems. We
propose multi-color
HST imaging to confirm and measure a sample of twenty
spiral lenses,
covering a range of bulge to disk ratios. By combining
dynamical lensing
and stellar population information for this unique sample
we will
deliver the first statistical constraints on halos and
disk properties,
and a new stringent test of disk galaxy formation
theories.
FGS 11945
Asteroseismology of Extrasolar Planet Host Stars
Detections of stellar oscillations, although a very
demanding task in
terms of observing time, offers a return of more accurate
knowledge
about the structure of stars than can be obtained in any
other way. In
particular, detecting the 10-15 highest amplitude modes in
solar-like
stars to signal-to-noise of just a few sigma each allows
robust
constraints on the stellar density to <1%, and the
stellar age to within
5-10% of its main sequence lifetime. Ten day observing
runs using the
FGS as a photometer on any of the 5 best transiting planet
systems would
enable these asteroseismology returns. From more precisely
observed
transit shapes than can be obtained from the ground a
completely
independent constraint on stellar density to ~1% can be
obtained. The
long observation sets required for asteroseismology also
provide an
excellent opportunity of detecting transits from other
planets, e.g.
hypothesized inner -orbit Hot Earths, should any exist.
FGS 11943/11944
Binaries at the Extremes of the H-R Diagram
We propose to use HST/Fine Guidance Sensor 1r to survey
for binaries
among some of the most massive, least massive, and oldest
stars in our
part of the Galaxy. FGS allows us to spatially resolve
binary systems
that are too faint for ground-based, speckle or optical
long baseline
interferometry, and too close to resolve with AO. We
propose a
SNAP-style program of single orbit FGS TRANS mode
observations of very
massive stars in the cluster NGC 3603, luminous blue
variables, nearby
low mass main sequence stars, cool subdwarf stars, and
white dwarfs.
These observations will help us to (1) identify systems
suitable for
follow up studies for mass determination, (2) study the
role of binaries
in stellar birth and in advanced evolutionary states, (3)
explore the
fundamental properties of stars near the main
sequence-brown dwarf
boundary, (4) understand the role of binaries for X-ray
bright systems,
(5) find binaries among ancient and nearby subdwarf stars,
and (6) help
calibrate the white dwarf mass - radius relation.
WFPC2 11797
Supplemental WFPC2 CYCLE 16 Intflat Linearity Check and
Filter Rotation
Anomaly Monitor
Supplemental observations to 11029, to cover period from
Aug 08 to SM4.
Intflat observations will be taken to provide a linearity
check: the
linearity test consists of a series of intflats in F555W,
in each gain
and each shutter. A combination of intflats, visflats, and
earthflats
will be used to check the repeatability of filter wheel
motions.
(Intflat sequences tied to decons, visits 1-18 in prop
10363, have been
moved to the cycle 15 decon proposal 11022 for easier
scheduling.)
Note: long-exposure WFPC2 intflats must be scheduled
during ACS anneals
to prevent stray light from the WFPC2 lamps from
contaminating long ACS
external exposures.
Note: These are supplemental observations to cover June to
SM4 (Oct 8
'08) + 6 months.
WFPC2 11796
WFPC2 Cycle 16 Decontaminations and Associated
Observations
This proposal is for the WFPC2 decons. Also included are
instrument
monitors tied to decons: photometric stability check,
focus monitor,
pre- and post-decon internals (bias, intflats, kspots,
& darks), UV
throughput check, VISFLAT sweep, and internal UV flat
check.
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.
WFPC2 11590
Observing the IR Catastrophe in a Deflagration Type Ia
Supernova
Our lack of understanding of Type Ia
supernova (SN Ia) explosions limits
our confidence in their use for cosmology. While there is
broad
agreement that these objects represent the explosions of
white dwarfs,
the details of the explosion mechanism are not
well-understood.
Recently, we have identified an internally homogeneous
subclass of SNe
Ia whose photometric and spectroscopic peculiarities make
them quite
distinct from normal SNe Ia. Models suggest we may be
seeing the result
of an explosion with a subsonic burning front, called a
deflagration. We
propose to test SN Ia models by obtaining late-time
photometry for SN
2008A, a recent, nearby example of this subclass, using
ACS and WFC3 on
HST. We will accurately measure the late-time photometric
decline rate
and spectral energy distribution (SED). These observations
will allow us
to test whether the ejecta contain the large amount of
oxygen predicted
by certain models. We also aim to detect major evolution
of the SED
expected due to the "IR catastrophe, " a change
in the dominant cooling
mechanism in the ejecta, as generically predicted by
models but only
hinted at by current observations.
WFPC2 11196
An Ultraviolet Survey of Luminous Infrared Galaxies in the
Local
Universe
At luminosities above 10^11.4 L_sun, the space density of
far-infrared
selected galaxies exceeds that of optically selected
galaxies. These
Luminous Infrared Galaxies {LIRGs} are primarily
interacting or merging
disk galaxies undergoing starbursts and creating/fueling
central AGN. We
propose far {ACS/SBC/F140LP} and near {WFPC2/PC/F218W} UV
imaging of a
sample of 27 galaxies drawn from the complete IRAS Revised
Bright Galaxy
Sample {RBGS} LIRGs sample and known, from our Cycle 14 B
and I-band ACS
imaging observations, to have significant numbers of
bright {23 < B < 21
mag} star clusters in the central 30 arcsec. The HST UV
data will be
combined with previously obtained HST, Spitzer, and GALEX
images to {i}
calculate the ages of the clusters as function of merger
stage, {ii}
measure the amount of UV light in massive star clusters
relative to
diffuse regions of star formation, {iii} assess the
feasibility of using
the UV slope to predict the far-IR luminosity {and thus
the star
formation rate} both among and within IR-luminous
galaxies, and {iv}
provide a much needed catalog of rest- frame UV
morphologies for
comparison with rest-frame UV images of high-z LIRGs and
Lyman Break
Galaxies. These observations will achieve the resolution
required to
perform both detailed photometry of compact structures and
spatial
correlations between UV and redder wavelengths for a
physical
interpretation our IRX-Beta results. The HST UV data,
combined with the
HST ACS, Spitzer, Chandra, and GALEX observations of this
sample, will
result in the most comprehensive study of luminous
starburst galaxies to
date.
WFPC2 11013
Continued M31 Monitoring for Black Hole X-ray Nova
We have been carring out a Chandra (GO+GTO) and HST (GO)
program to find
Black Hole X-ray Nova (BHXN) and their optical
counterparts in M31 for
several years. To date we have found >2 dozen BHXN and
3 HST optical
counterparts for these BHXN. Our results suggest a rather
high ratio of
BH to neutron star (NS) binaries, or a high duty cycle for
the BHXN. We
propose to continue this program, with the goal of
determining the
orbital period distribution and duty cycles of these BHXN.
Current
results yield 3 orbital periods and 3 upper limits. Our
proposed
observations will ~double the total number of periods and
therefore
yield sufficient numbers to make a first approximation of
the orbital
period distribution. The orbital period distribution is
the fundamental
observable parameter any binary stellar evolution models
must match, and
the duty cycle is very poorly known but directly
influences the binary
lifetime. M31 is the only galaxy in which this
extra-galactic study of
BHXN is feasible. Furthermore, the 2 HST observations will
allow us to
estimate the orbital period of a single super-Eddington
source.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
11694 - At 052/01:12:56, GSAcq (2,3,2) scheduled from
052/01:09:14 -
01:16:41 resulted in Fine Lock Back-up (2,0,2).
0bservations possibly affected: Astrometry Proposal ID# 11943
11695 - REAcq (1,2,2) at 053/18:31:22 failed to RGA
control with QF1STOPF
and QSTOP flags set.
Observations affected: WFPC 202 to 203, Proposal ID# 11986.
COMPLETED OPS REQUEST:
18404-0 - Uplink new FGS Alignment tables for 054 SMS @
054/0019z
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS GSacq
18
18
FGS
REacq
22
21
OBAD with Maneuver
50
50
SIGNIFICANT EVENTS:
The new FGS alignments were successfully uplinked tonight
at the start
of the 054 SMS at 2009.054/00:20. The first Guide star
acquisition on
the SMS was successful