HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 4152
PERIOD COVERED: UT July 10, 2006 (DOY 191)
OBSERVATIONS SCHEDULED
ACS/HRC 10512
Search for Binaries Among Faint Jupiter Trojan Asteroids
We propose an ambitious SNAPSHOT program to survey faint Jupiter
Trojan
asteroids for binary companions. We target 150 objects, with the
expectation of acquiring data on about 50%. These objects span Vmag
=
17.5-19.5, a range inaccessible with ground-based adaptive optics.
We
now have a significant sample from our survey of brighter Trojans to
suggest that the binary fraction is similar to that which we find
among
brighter main-belt asteroids, roughly 2%. However, our observations
suggest a higher binary fraction for smaller main-belt asteroids,
probably the result of a different formation mechanism {evident also
from the physical characteristics of the binaries}. Because the
collision environment among the Trojans is similar to that of the
Main
Belt, while the composition is likely to be very different, sampling
the
binary fraction among the fainter Trojans should help us understand
the
collisional and binary formation mechanisms at work in various
populations, including the Kuiper Belt, and help us evaluate
theories
for the origin of the Trojans. Calibration of and constraints on
models
of binary production and collisional evolution can only be done
using
these large-scale, real-life physical systems that we are beginning
now
to find and utilize.
ACS/HRC/WFC 10758
ACS CCDs daily monitor
This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in
ACS CCD detectors. The files, biases and dark will be used to create
reference files for science calibration. This programme will be for
the
entire lifetime of ACS. Changes from cycle 13:- The default gain for
WFC
is 2 e-/DN. As before bias frames will be collected for both gain 1
and
gain 2. Dark frames are acquired using the default gain {2}. This
program cover the period May, 31 2006- Oct, 1-2006. The first half
of
the program has a different proposal number: 10729.
ACS/WFC 10503
The Star Formation Histories of Early Type Dwarf Galaxies in Low
Density
Environments: Clues from the Sculptor Group
We seek HST ACS/WFC time to conduct a detailed study of the stellar
populations of 5 early-type {dE, dE/dIrr} dwarf galaxies in the
nearby
{~1.5 to 4 Mpc} Sculptor group. Four of these systems have been
recently
found to contain modest amounts of HI, and existing ground-based and
HST
snapshot data point to the potential presence of small populations
of
young {blue} stars in at least three of these systems. Consequently,
they resemble the Local Group 'transition' objects Phoenix and LGS3.
The
relative number of such transition systems is thus substantially
larger
in the low density environment of the Scl group than for the Local
Group. Detailed stellar populations studies will allow estimation of
the
star formation histories, via stellar population modelling of the
color-
magnitude diagrams, of the target dwarfs, which in turn will connect
to
gas consumption and retention rates. For the two nearer dwarfs we aim
to
reach below the horizontal branch {a first for any system beyond the
Local Group} equivalent to a main sequence turnoff age of ~1 Gyr.
The
observations of these two systems will also allow detection of RR
Lyrae
variables and thus direct confirmation of the presence of old
populations. For the other three dwarfs will we cover the first 2.5
mags
of the red giant branch, equivalent to the main sequence termination
for
a ~300 Myr population. The results will have implications for
theories
of galaxy formation and evolution, particularly with regard to the
evolutionary relation between low luminosity dEs and dwarf irregulars.
ACS/WFC 10592
An ACS Survey of a Complete Sample 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 enhanced star formation and Active
Galactic Nuclei {AGN} activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
ACS/WFC imaging of a complete sample of 88 L_IR > 10^11.4 L_sun
luminous
infrared galaxies in the IRAS Revised Bright Galaxy Sample {RBGS:
i.e.,
60 micron flux density > 5.24 Jy}. This sample is ideal not only in
its
completeness and sample size, but also in the proximity and
brightness
of the galaxies. The superb sensitivity, resolution, and field of
view
of ACS/WFC on HST enables a unique opportunity to study the detailed
structure of galaxies that sample all stages of the merger process.
Imaging will be done with the F439W and F814W filters {B and I-band}
to
examine as a function of both luminosity and merger state {i} the
evidence at optical wavelengths of star formation and AGN activity
and
the manner in which instabilities {bars and bridges} in the galaxies
may
funnel material to these active regions, {ii} the relationship
between
star formation and AGN activity, and {iii} the structural properties
{AGN, bulge, and disk components} and fundamental parameters
{effective
radius and surface brightness} of LIRGs and their similarity with
putative evolutionary byproducts {elliptical, S0 and classical AGN
host
galaxies}. This HST survey will also bridge the wavelength gap between
a
Spitzer imaging survey {covering seven bands in the 3.6-160 micron
range} and a GALEX UV imaging survey of these galaxies, but will
resolve
complexes of star clusters and multiple nuclei at resolutions well
beyond the capabilities of either Spitzer or GALEX. The combined
datasets will result in the most comprehensive multiwavelength study
of
interacting and merging galaxies to date.
ACS/WFC 10624
Solving the Mystery of the Short-Hard Gamma-Ray Bursts
Eight years after the afterglow detections that revolutionized
studies
of the long-soft gamma-ray bursts, not even one afterglow of a
short-hard GRB has been seen, and the nature of these events has
become
one of the most important problems in GRB research. The Swift
satellite,
expected to be in full operation throughout Cycle 14, will report
few-arcsecond localizations for short-hard bursts in minutes,
enabling
prompt, deep optical afterglow searches for the first time.
Discovery
and observation of the first short-hard optical afterglows will
answer
most of the critical questions about these events: What are their
distances and energies? Do they occur in distant galaxies, and if so,
in
which regions of those galaxies? Are they the result of collimated
or
quasi-spherical explosions? In combination with an extensive
rapid-response ground-based campaign, we propose to make the
critical
high-sensitivity HST TOO observations that will allow us to answer
these
questions. If theorists are correct in attributing the short-hard
bursts
to binary neutron star coalescence events, then they will serve as
signposts to the primary targeted source population for ground-based
gravitational-wave detectors, and short-hard burst studies will have
a
vital role to play in guiding those observations.
NIC1/NIC2/NIC3 8794
NICMOS Post-SAA calibration - CR Persistence Part 5
A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the
SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel
in all three NICMOS Cameras. The POST-SAA darks will be non-standard
reference files available to users with a USEAFTER date/time mark.
The
keyword 'USEAFTER=date/time' will also be added to the header of
each
POST-SAA DARK frame. The keyword must be populated with the time, in
addition to the date, because HST crosses the SAA ~8 times per day
so
each POST-SAA DARK will need to have the appropriate time specified,
for
users to identify the ones they need. Both the raw and processed
images
will be archived as POST-SAA DARKSs. Generally we expect that all
NICMOS
science/calibration observations started within 50 minutes of leaving
an
SAA will need such maps to remove the CR persistence from the
science
images. Each observation will need its own CRMAP, as different SAA
passages leave different imprints on the NICMOS detectors.
NIC3/ACS/WFC 10504
Characterizing the Sources Responsible for Cosmic Reionization
Our group has demonstrated the role that massive clusters, acting as
powerful cosmic lenses, can play in constraining the abundance and
properties of low-luminosity star-forming sources beyond z~6; such
sources are thought to be responsible for ending cosmic
reionization.
The large magnification possible in the critical regions of
well-constrained clusters brings sources into view that lie at or
beyond
the limits of conventional exposures such as the UDF, as well as
those
in imaging surveys being undertaken with IRAC onboard Spitzer. We
have
shown that the combination of HST and Spitzer is particularly
effective
in delivering the physical properties of these distant sources,
constraining their mass, age and past star formation history.
Indirectly, we therefore gain a valuable glimpse to yet earlier
epochs.
Recognizing the result {and limitations} of the UDF exposure, we
propose
a systematic search through 6 lensing clusters with ACS and NICMOS
for
further z~6-7 sources in conjunction with existing deep IRAC data.
Our
survey will mitigate cosmic variance and extend the search both to
lower
luminosities and, by virtue of the NICMOS/IRAC combination, to
higher
redshift. The goal is to count and characterize representative
sources
at z~6-10 and to delineate the redshift range of activity for the
planning of future observations.
WFPC2 10534
Active Atmospheres on Uranus and Neptune
We propose Snapshot observations of Uranus and Neptune to monitor
changes in their atmospheres on time scales of weeks, months, and
years.
Uranus is rapidly approaching equinox in 2007, with another 4 degrees
of
latitude becoming visible every year. Recent HST observations during
this epoch {including 6818: Hammel, Lockwood, and Rages; 8680:
Hammel,
Rages, Lockwood, and Marley; 8634: Rages, Hammel, Lockwood, Marley,
and
McKay; and 10170: Rages, Hammel, Lockwood, and Marley} have revealed
strongly wavelength-dependent latitudinal structure and the presence
of
numerous visible-wavelength cloud features in the northern
hemisphere.
Long- term ground-based observations {Lockwood and Thompson 1999}
show
seasonal brightness changes whose origins are not well understood.
Recent near-IR images of Neptune obtained using adaptive optics on
the
Keck Telesccope together with images from our Cycle 9 Snapshot
program
{8634} show a general increase in activity at south temperate
latitudes
as well as the possible development of another Great Dark Spot.
Further
Snapshot observations of these two dynamic planets will elucidate
the
nature of long-term changes in their zonal atmospheric bands and
clarify
the processes of formation, evolution, and dissipation of discrete
albedo features.
WFPC2 10748
WFPC2 CYCLE 14 Standard Darks
This dark calibration program obtains dark frames every week in order
to
provide data for the ongoing calibration of the CCD dark current
rate,
and to monitor and characterize the evolution of hot pixels. Over an
extended period these data will also provide a monitor of radiation
damage to the CCDs.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary
reports
of potential non-nominal performance that will be investigated.)
HSTARS:
#10351 - GSAcq(2,3,2) Failed to RGA Control @ 191/1553z
The
GSAcq(2,3,2) scheduled at 191/15:53:34 - 16:01:39 failed to RGA Hold
due to
stop flag (QF2STOPF) indication on FGS-2. Pre-acquisition OBADs
had (RSS)
attitude error corrections values of 5160.83 and 10.42
arcseconds. Post-acquisition OBAD/MAP not scheduled. Possible
Observations affected: ACS 38.
#10352 - REACQ(2,3,2) fails to RGA control @ 191/1847z
At
acquisition of signal at 191/19:06:09, vehicle was in gyro control
with
QF2STOPF and QSTOP flags set. REACQ(2,3,2) at 191/18:47:18 failed
to acquire
lock. No Scan Step Limit or Search Radius Limit flags were
seen.
GSACQ(2,3,2) at 15:54:19 and REACQ(2,3,2) at 17:11:15 were
successful. REACQ(2,3,2) at 20:23:12 was also successful.
Observations
affected:
ACS 43 to 46. GSAcq(2,3,2) @ 15:54:19 failed to RGA Hold,
reference
HSTAR #10351.
#10355 GSAcq (2,3,2) failed due to search radius limit exceeded
@192/08:51:53z
GSAcq
(2,3,2) scheduled at 192/08:46:56-08:54:28 failed to RGA control
due to
search radius limit exceeded on FGS 2. Possible observations
effected:
ACS 62 At 192/08:41:14) received two 486 ESB 1805's (FHST
Moving
target detected). Pre-acquisition OBADs had (RSS) attitude error
corrections values of 1578.03 and 12.04 arc-seconds.
Post-acquisition
OBAD/MAP
not scheduled. At 192/08:59:26 received 486 ESB a07 (CT
TIMEOUT IN
DET DV).
COMPLETED OPS REQUEST:
#17819-1 Install SMAC20 Versions K & L @ 191/1925z
#17813-1 Enable ESBs 1201 and 1202 for Battery 3 BCT @ 192/0749z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS
GSacq
10
8
191/1553z (HSTAR 10351)
192/0851z (HSTAR 10355)
FGS
REacq
5
4
191/1847z (HSTAR 10352)
OBAD with Maneuver
26
26
SIGNIFICANT EVENTS: (None)
-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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