HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4761
PERIOD COVERED: 5am December 19 - 5am December 22, 2008
(DOY
354/1000z-357/1000z)
OBSERVATIONS SCHEDULED
WFPC2 11962
A New Supernova in the Antennae; Narrowing in on the
Hubble Constant and
Dark Energy
A measurement of the Hubble constant to a precision of a
few percent
would be a powerful aid to the investigation of the nature
of dark
energy and a potent "end-to-end" test of the
present cosmological model.
In Cycle 15 we constructed a new, streamlined distance
ladder utilizing
high-quality type Ia supernova data and observations of
Cepheids with
HST in the near-IR to minimize the dominant sources of
systematic
uncertainty in past measurements of the Hubble constant
and reduce its
total uncertainty to a little under 5%. Here we propose to
exploit this
new route with a rare opportunity to begin reducing the
remaining
uncertainty. SN 2007sr in the Antennae (NGC 4038/9) is the
rare SN Ia
which is suitable for increasing the precision of small
calibration
sample of
Cepheids are within range of observing with WFPC2 (and
NICMOS, should it
return to life). But we need to act fast as the window of
long
visibility and fixed orient runs from mid-early December
2008 to early
March 2009. We request 34 orbits with WFPC2 to find the
Cepheids in the
SN host. We also request 16 orbits to observe the Cepheids
we find with
Camera 2, F160W if NICMOS becomes available by April 2009
. (If NICMOS
does not return we would forgo these observations and ask
the TTRB to
let us make them with our own WFC3-IR allocation, though
we much prefer
the smaller pixel size of NIC2).
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.
WFPC2 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 to observe using 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.
FGS 11943
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.
FGS 11870
Calibrating FGS1R's Optical Field Angle Distortion (OFAD),
Second Epoch
This proposal gathers the data needed to calibrate the
optical field
angle distortions in FGS1r to the level of accuracy
required for
astrometry science. Selected stars from the galactic
cluster M35 are
repeatedly observed in POSITION mode by FGS1r with F583W
filter at a
variety of spacecraft pointings and telescope roll angles.
Ideally the
observations are to occur at a time when this ecliptic
star field is
near the anti-sun direction so that HST's roll angle is
unconstrained.
Unfortunately this is not possible under two gyro
operations. Therefore,
the observations in this proposal are somewhat very
constrained in roll.
However, this test should suffice as an adequate update to
the original
FGS1r OFAD that executed in December 2000. For each visit,
the desired
telescope pointing is specified by POS TARG and ORIENT
special
requirements.
FGS 11704
The Ages of Globular Clusters and the Population II
Distance Scale
Globular clusters are the oldest objects in the universe
whose age can
be accurately determined. The dominant error in globular
cluster age
determinations is the uncertain Population II distance
scale. We propose
to use FGS 1r to obtain parallaxes with an accuracy of 0.2
milliarcsecond for 9 main sequence stars with [Fe/H] <
-1.5. This will
determine the absolute magnitude of these stars with
accuracies of 0.04
to 0.06mag. This data will be used to determine the
distance to 24
metal-poor globular clusters using main sequence fitting.
These
distances (with errors of 0.05 mag) will be used to
determine the ages
of globular clusters using the luminosity of the subgiant
branch as an
age indicator. This will yield absolute ages with an
accuracy 5%, about
a factor of two improvement over current estimates.
Coupled with
existing parallaxes for more metal-rich stars, we will be
able to
accurately determine the age for globular clusters over a
wide range of
metallicities in order to study the early formation
history of the Milky
Way and provide an independent estimate of the age of the
universe.
The Hipparcos database contains only 1 star with [Fe/H]
< -1.4 and an
absolute magnitude error less than 0.18 mag which is
suitable for use in
main sequence fitting. Previous attempts at main sequence
fitting to
metal-poor globular clusters have had to rely on
theoretical
calibrations of the color of the main sequence. Our HST
parallax program
will remove this source of possible systematic error and
yield distances
to metal-poor globular clusters which are significantly
more accurate
than possible with the current parallax data. The HST
parallax data will
have errors which are 10 times smaller than the current
parallax data.
Using the HST parallaxes, we will obtain main sequence
fitting distances
to 11 globular clusters which contain over 500 RR Lyrae
stars. This will
allow us to calibrate the absolute magnitude of RR Lyrae
stars, a
commonly used Population II distance indicator.
WFPC2 11316
HST Cycle 16 & Pre-SM4 Optical Monitor
This is a continuation of the Cycle 15 & pre-SM4
Optical Monitor, 11020.
Please see that proposal for a more complete description
of the
observing strategy. The 6 visits comprising this proposal observe
two
single standard stars with WFPC2/PC in order to establish
overall OTA
focal length for the purposes of focus maintenance. The
goal of this
monitoring before SM4 is to establish a best estimate of
the OTA focus
entering SMOV.
WFPC2 11289
SL2S: The Strong Lensing Legacy Survey
Recent systematic surveys of strong galaxy-galaxy lenses
{CLASS, SLACS,
GOODS, etc.} are producing spectacular results for galaxy
masses roughly
below a transition mass M~10^13 Mo. The observed lens
properties and
their evolution up to z~0.2, consistent with numerical
simulations, can
be described by isothermal elliptical potentials. In
contrast, modeling
of giant arcs in X-ray luminous clusters {halo masses M
>~10^13 Mo}
favors NFW mass profiles, suggesting that dark matter
halos are not
significantly affected by baryon cooling. Until recently,
lensing
surveys were neither deep nor extended enough to probe the
intermediate
mass density regime, which is fundamental for
understanding the assembly
of structures. The CFHT Legacy Survey now covers 125
square degrees, and
thus offers a large reservoir of strong lenses probing a
large range of
mass densities up to z~1. We have extracted a list of 150
strong lenses
using the most recent CFHTLS data release via automated
procedures.
Following our first SNAPSHOT proposal in cycle 15, we
propose to
continue the Hubble follow-up targeting a larger list of
130 lensing
candidates. These are intermediate mass range candidates
{between
galaxies and clusters} that are selected in the redshift
range of 0.2-1
with no a priori X-ray selection. The HST resolution is
necessary for
confirming the lensing candidates, accurate modeling of
the lenses, and
probing the total mass concentration in galaxy groups up
to z~1 with the
largest unbiased sample available to date.
FGS 11213
Distances to Eclipsing M Dwarf Binaries
We propose HST FGS observations to measure accurate
distances of 5
nearby M dwarf eclipsing binary systems, from which
model-independent
luminosities can be calculated. These objects have either
poor or no
existing parallax measurements. FGS parallax
determinations for these
systems, with their existing dynamic masses determined to
better than
0.5%, would serve as model-independent anchor points for
the low-mass
end of the mass-luminosity diagram.
FGS 11212
Filling the Period Gap for Massive Binaries
The current census of binaries among the massive O-type
stars is
seriously incomplete for systems in the period range from
years to
millennia because the radial velocity variations are too
small and the
angular separations too close for easy detection. Here we
propose to
discover binaries in this observational gap through a
Faint Guidance
Sensor SNAP survey of relatively bright targets listed in
the Galactic O
Star Catalog. Our primary goal is to determine the binary
frequency
among those in the cluster/association, field, and runaway
groups. The
results will help us assess the role of binaries in
massive star
formation and in the processes that lead to the ejection
of massive
stars from their natal clusters. The program will also
lead to the
identification of new, close binaries that will be targets
of long term
spectroscopic and high angular resolution observations to
determine
their masses and distances. The results will also be
important for the
interpretation of the spectra of suspected and newly
identified binary
and multiple systems.
WFPC2 11113
Binaries in the Kuiper Belt: Probes of Solar System
Formation and
Evolution
The discovery of binaries in the Kuiper Belt and related
small body
populations is powering a revolutionary step forward in
the study of
this remote region. Three quarters of the known binaries
in the Kuiper
Belt have been discovered with HST, most by our snapshot
surveys. The
statistics derived from this work are beginning to yield
surprising and
unexpected results. We have found a strong concentration
of binaries
among low-inclination Classicals, a possible size cutoff
to binaries
among the Centaurs, an apparent preference for nearly
equal mass
binaries, and a strong increase in the number of binaries
at small
separations. We propose to continue this successful
program in Cycle 16;
we expect to discover at least 13 new binary systems,
targeted to
subgroups where these discoveries can have the greatest
impact.
ACS/HRC 10877
A Snapshot Survey of the Sites of Recent, Nearby
Supernovae
During the past few years, robotic {or nearly robotic}
searches for
supernovae {SNe}, most notably our Lick Observatory
Supernova Search
{LOSS}, have found hundreds of SNe, many of them in quite
nearby
galaxies {cz < 4000 km/s}. Most of the objects were
discovered before
maximum brightness, and have follow-up photometry and
spectroscopy; they
include some of the best-studied SNe to date. We propose
to conduct a
snapshot imaging survey of the sites of some of these
nearby objects, to
obtain late-time photometry that {through the shape of the
light and
color curves} will help reveal the origin of their lingering
energy. The
images will also provide high-resolution information on
the local
environments of SNe that are far superior to what we can
procure from
the ground. For example, we will obtain color-color and
color-magnitude
diagrams of stars in these SN sites, to determine the SN
progenitor
masses and constraints on the reddening. Recovery of the
SNe in the new
HST images will also allow us to actually pinpoint their
progenitor
stars in cases where pre- explosion images exist in the
HST archive.
This proposal is an extension of our successful Cycle 13
snapshot survey
with ACS. It is complementary to our Cycle 15 archival
proposal, which
is a continuation of our long-standing program to use
existing HST
images to glean information about SN environments.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
11620 - NCC (NICMOS CRYO-COOLER) SAFED @ 354/1827z
11621 - GSAcq (2,3,2) Loss of Lock while guiding @
356/1922
A
Loss of Lock occurred on FGS 2 while guiding under FGSs 2 & 3.
Observations
affected: Astrometry Proposal # 11213
COMPLETED OPS REQUEST:
18376-0 - Off-Line +BB SPA Trim Relay
18377-0 - Lower FGS-1R K16 K-factor for Proposal 11945
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL FAILURE TIMES
FGS GSacq 28
28
FGS REacq 13
13
OBAD with Maneuver
82 82
LOSS of
LOCK
356/1922z
SIGNIFICANT EVENTS:
Flash Report: Off-Line +BB SPA Trim Relay (OR #18376) from
upcoming hot period from DOY 348 until DOY 362.
Flash Report: FGS-1R K16 K-factor lowered to a value of
4982 as
preparation for 10 day Astrometry Proposal #11945 that
started at
357/01:30z.