HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 4158
PERIOD COVERED: UT July 18, 2006 (DOY 199)
OBSERVATIONS SCHEDULED
ACS/HRC 10598
ACS Imaging of Fomalhaut: A Rosetta Stone for Debris Disks Sculpted
by
Planets
The Sun and roughly 15% of stars are surrounded by dust disks
collisionally replenished by asteroids and comets. Disk structure can
be
directly tied to the dynamical influence of more massive bodies such
as
planets. For example, planetary perturbations offset the center of
our
zodiacal dust disk ~0.01 AU away from the Sun and also maintain a ~40
AU
radius inner edge to our Kuiper Belt. Here we propose follow-up
observation to the first optical detection of reflected light from
dust
grains surrounding the nearby star Fomalhaut using HST/ACS. We find
a
belt of material between 133 and 158 AU radius that has a center
position offset ~15 AU from the stellar position, and with a sharp
inner
edge. A tenuous dust component interior to the belt is also detected
in
the southeast. Given Fomalhaut's proximity to the Sun {7.7 pc},
these
images represent the closest and highest angular resolution view of
an
extrasolar analog to our Kuiper Belt. The center of symmetry offset
and
the sharp inner edge of Fomalhaut's belt are evidence for
planet-mass
objects orbiting the star as predicted by dynamical theory and
simulations. We propose comprehensive follow-up ACS imaging to fully
exploit this discovery and map the disk around its entire
circumference
with higher signal-to-noise and at multiple wavelengths. HST/ACS is
certainly the only facility capable of performing this relatively
wide
field optical study at high contrast ratios and diffraction-limited
resolution. The Cycle 14 data will provide key measurements of belt
width as a function of azimuth, the scattered light color of the
belt
versus the inner dust component, and the azimuthal structure of the
belt. These data will be used to constrain dynamical models of
resonances and shepherding that ultimately elucidate the dynamical
properties of planet-mass objects in the system.
ACS/HRC 10738
Earth Flats
Sky flats will be obtained by observing the bright Earth with the
HRC
and WFC. These observations will be used to verify the accuracy of
the
flats currently in the pipeline and to monitor any changes. Weekly
coronagraphic monitoring is required to assess the changing position
of
the spots.
ACS/HRC/WFC 10737
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 detectors. A moderately crowded stellar
field in the cluster 47 Tuc is observed every three months with the
HRC
{at the cluster core} and WFC {6' 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. An additional
orbit is required to compare WFC observations taken at gain 1 with
those
taken at the new default gain 2.
ACS/WFC 10551
Gamma-Ray Bursts from Start to Finish: A Legacy Approach
The progenitors of long-duration GRBs are now known to be massive
stars.
This result lends credence to the collapsar model, where a rotating
massive star ends its life leaving a black hole or a highly
magnetized
neutron star, and confirms its essential aspects. The focus of
attention
now is on the black hole or magnetar engines that power the bursts.
Somehow these engines create the most highly relativistic and highly
collimated outflows that we know of, through mechanisms that no
current
theory can explain. These astrophysical laboratories challenge our
understanding of relativistic shocks, of mechanisms for extracting
energy from a black hole, and of how physics works in extreme
conditions. The launch of Swift is bringing us into a new era, where
we
can make broadband observations that will enable us to study these
fascinating physical processes. We propose here an ambitious,
comprehensive program to obtain the datasets that will become the
standard that any successful model for the central engine must
explain.
This programs leverages the HST observations to the maximum extent
by
our commitment of Swift observations, a Large program at the VLA,
and
extensive ground-based optical resources. By studying the engines
and
searching for jets in a variety of events, this program will
investigate
the conditions necessary for the engine and jet formation itself.
ACS/WFC 10629
Are Field OB Stars Alone?
This SNAP program offers an inexpensive, simple program to search
for
low-mass companions of field OB stars. Do field OB stars exist in
true
isolation, as suggested by a recent Galactic study, or are they the
tip
of the iceberg on a small cluster of low-mass stars as predicted by
the
cluster mass function and stellar IMF? Short ACS/WFC V and I
observations proposed here may easily resolve this issue for field
OB
stars in the Small Magellanic Cloud. Truly isolated OB stars represent
a
theoretical challenge and variation from clusters, in mode of star
formation, and have important consequences for our understanding of
the
field stellar population in galaxies. Small clusters around the field
OB
stars, on the other hand, may confirm the universality of the
stellar
clustering law and IMF.
ACS/WFC/NIC2 10496
Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae
and Clusters
We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available
with the
previous GOODS searches. Moreover, this approach provides a
strikingly
more efficient search-and-follow-up that is primarily pre-scheduled.
The
resulting dark energy measurements do not share the major systematic
uncertainty at these redshifts, that of the extinction correction with
a
prior. By targeting massive galaxy clusters at z > 1 we obtain a
five-times higher efficiency in detection of Type Ia supernovae in
ellipticals, providing a well-understood host galaxy environment.
These
same deep cluster images then also yield fundamental calibrations
required for future weak lensing and Sunyaev-Zel'dovich measurements
of
dark energy, as well as an entire program of cluster studies. The
data
will make possible a factor of two improvement on supernova
constraints
on dark energy time variation, and much larger improvement in
systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.
CAL/ACS 10735
SBC MAMA Recovery
This proposal is designed for the initial turn-on of the ACS MAMA
detector and to permit recovery after an anomalous shutdown.
Anomalous
shutdowns can occur as a result of bright object violations which
trigger the Bright Scene Detection or Software Global Monitors.
Anomalous shutdowns can also occur as a result of MAMA hardware
problems. The Initial MAMA turn-on/recovery from anomalous shutdown
consists of three tests: a signal processing electronics check, high
voltage ramp-up to an intermediate voltage, and high voltage ramp-up
to
the full operating voltage. During each of the two high voltage
ramp-ups, diagnostics are performed during a dark ACCUM. The turn-on
is
followed by a MAMA Fold Analysis . The complete sequence is contained
in
visits 1 through 4. If a second execution is required during cycle
13,
visits 5 through 8 will be run and another proposal prepared for
possible future occurrences.
WFPC2 10745
WFPC2 CYCLE 14 INTERNAL MONITOR
This calibration proposal is the Cycle 14 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.
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:
#17852-0 - GenSlew for Proposal 10598 slot#13 @200/1621z
#17853-0 - GenSlew for Proposal 10598 slot#14 @200/1821z
#17854-0 - GenSlew for Proposal 10598 slot#1 @200/1957z
#17857-0 - GenSlew for Proposal 10598 slot#2 @200/2149z
#17855-1 - Clear ACS Event Flag 2 @199/1818z
#17856-0 - Restore VTFE to K1L4 @199/2012z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSacq
12 12
FGS
REacq
04 04
OBAD with Maneuver
28 28
SIGNIFICANT EVENTS: (None)
Raised VTFE to K1L4 Flash Report
At approximately DOY 199/2012 GMT (Tuesday, 7/18, 4:12pm local), the
VTFE was reset to the nominal K1L4 level. (The VTFE had been reduced
to
K1L4-150mV on DOY 196. Additionally, the +CC SPA was taken
off-line.)
EPS will determine the appropriate time to place the +CC SPA back
on-line.
-Lynn
Lynn F. Bassford
CHAMP HST Missions Operations Manager
Lockheed Martin Technical Operations
GSFC PH#: 301-286-2876
"The Hubble Space Telescope is the Babe Ruth of astronomical
observatories, the Muhammad Ali of cosmic photography
"
- Robert Roy Britt, space.com 7-14-4
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