HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4744
PERIOD COVERED: 5am November 24 - 5am November 25, 2008
(DOY
329/1000z-330/1000z)
OBSERVATIONS SCHEDULED
WFPC2 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.
ACS/SBC 11110
Searching for Lyman Apha Emission from FUSE Lyman
Continuum Candidates
We have recently been granted time on FUSE to characterize
the escape
fraction of hydrogen Lyman continuum (Lyc) photons from a
morphologically diverse set of star forming galaxies. The
FUSE program
is designed to provide ~ 5 sigma detections of Lyc photons
emitted from
star forming galaxies with escape fractions ~5%. With this
proposal we
seek hydrogen Lyman alpha (Lya) observations of a
representative subset
of the FUSE program targets to constrain the observational
relationship
between Lyc, Lya, and hydrogen Balmer line emission in
these systems.
Such observations explore the detailed balance between the
simple
optically thin (Case A) and optically thick (Case B)
limits in
recombination theory. The ultimate goal of this program is
to quantify
the relationship between escaping Lya and Lyc emission and
the first
structures that form in the early universe.
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
followup 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 11201
Systemic and Internal Motions of the Magellanic Clouds:
Third Epoch
Images
In Cycles 11 and 13 we obtained two epochs of ACS/HRC data
for fields in
the Magellanic Clouds centered on background quasars. We
used these data
to determine the proper motions of the LMC and SMC to
better than 5% and
15% respectively. These are by far the best determinations
of the proper
motions of these two galaxies. The results have a number
of unexpected
implications for the Milky Way-LMC-SMC system. The implied
three-dimensional velocities are larger than previously
believed, and
are not much less than the escape velocity in a standard
10^12 solar
mass Milky Way dark halo. Orbit calculations suggest the
Clouds may not
be bound to the Milky Way or may just be on their first
passage, both of
which would be unexpected in view of traditional
interpretations of the
Magellanic Stream. Alternatively, the Milky Way dark halo
may be a
factor of two more massive than previously believed, which
would be
surprising in view of other observational constraints.
Also, the
relative velocity between the LMC and SMC is larger than
expected,
leaving open the possibility that the Clouds may not be
bound to each
other. To further verify and refine our results we now request
an epoch
of WFPC2/PC data for the fields centered on 40 quasars
that have at
least one epoch of ACS imaging. We request execution in
snapshot mode,
as in our previous programs, to ensure the most efficient
use of HST
resources. A third epoch of data of these fields will
provide crucial
information to verify that there are no residual
systematic effects in
our previous measurements. More importantly, it will
increase the time
baseline from 2 to 5 yrs and will increase the number of
fields with at
least two epochs of data. This will reduce our
uncertainties
correspondingly, so that we can better address whether the
Clouds are
indeed bound to each other and to the Milky Way. It will
also allow us
to constrain the internal motions of various populations within
the
Clouds, and will allow us to determine a distance to the
LMC using
rotational parallax.
WFPC2 11793
WFPC2 Cycle 16 Internal Monitor
This calibration proposal is the Cycle 15 routine internal
monitor for
WFPC2, to be run weekly to monitor the health of the
cameras. A variety
of internal exposures are obtained in order to provide a
monitor of the
integrity of the CCD camera electronics in both bays (both
gain 7 and
gain 15 -- to test stability of gains and bias levels), a
test for
quantum efficiency in the CCDs, and a monitor for possible
buildup of
contaminants on the CCD windows. These also provide raw
data for
generating annual super-bias reference files for the
calibration
pipeline.
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.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
11584 - GSAcq(2,3,2) failed to RGA Hold during scheduled
The acquisition of signal (AOS) at 329/20:55:19 showed, GSAcq (2,3,2),
scheduled from 20:19:05 - 20:26:28 had failed to RGA Control due to
QF2STOPF flag on FGS-2.
Possible observations affected: Astrometry Proposal 11943
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS GSacq
07
06
FGS REacq
04
04
OBAD with Maneuver
22
22
SIGNIFICANT EVENTS: (None)