HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4548
PERIOD
COVERED: UT February 14, 2008 (DOY 045)
OBSERVATIONS
SCHEDULED
ACS/SBC
10862
Comprehensive
Auroral Imaging of Jupiter and Saturn during the
International
Heliophysical Year
A
comprehensive set of observations of the auroral emissions from
Jupiter
and Saturn is proposed for the International Heliophysical Year
in
2007, a unique period of especially concentrated measurements of
space
physics phenomena throughout the solar system. We propose to
determine
the physical relationship of the various auroral processes at
Jupiter
and Saturn with conditions in the solar wind at each planet.
This
can be accomplished with campaigns of observations, with a sampling
interval
not to exceed one day, covering at least one solar rotation.
The
solar wind plasma density approaching Jupiter will be measured by
the
New Horizons spacecraft, and a separate campaign near opposition in
May
2007 will determine the effect of large-scale variations in the
interplanetary
magnetic field {IMF} on the Jovian aurora by
extrapolation
from near-Earth solar wind measurements. A similar Saturn
campaign
near opposition in Jan. 2007 will combine extrapolated solar
wind
data with measurements from a wide range of locations within the
Saturn
magnetosphere by Cassini. In the course of making these
observations,
it will be possible to fully map the auroral footprints of
Io
and the other satellites to determine both the local magnetic field
geometry
and the controlling factors in the electromagnetic interaction
of
each satellite with the corotating magnetic field and plasma density.
Also
in the course of making these observations, the auroral emission
properties
will be compared with the properties of the near-IR
ionospheric
emissions {from ground-based observations} and non thermal
radio
emissions, from ground-based observations for Jupiter's decametric
radiation
and Cassini plasma wave measurements of the Saturn Kilometric
Radiation
{SKR}.
NIC1/NIC2/NIC3
8795
NICMOS Post-SAA calibration - CR Persistence Part 6
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 i
mages.
Each observation will need its own CRMAP, as different SAA
passages
leave different imprints on the NICMOS detectors.
NIC3
11236
Did
Rare, Large Escape-Fraction Galaxies Reionize the Universe?
Lyman
continuum photons produced in massive starbursts may have played a
dominant
role in the reionization of the Universe. Starbursts are
important
contributors to the ionizing metagalactic background at lower
redshifts
as well. However, their contribution to the background depends
upon
the fraction of ionizing radiation that escapes from the intrinsic
opacity
of galaxies below the Lyman limit. Current surveys suggest that
the
escape fraction is close to zero in most galaxies, even among young
starbursts,
but is large in 15-25% of them. Non-uniform escape fractions
are
expected as a result of violent events creating clear paths in small
parts
of galaxies. The number of galaxies observed with high escape
fraction
will result from the combination of the intrinsic number with
clear
lines of sight and their orientation with respect to the observer.
We
propose to measure the fraction of escaping Lyman continuum radiation
in
a large sample (47) of z~0.7 starbursts in the COSMOS field. These
compact
UV-luminous galaxies are good analogs to high redshift LBGs.
Using
the SBC/PR130L we can quickly (1-4 orbits) detect relative escape
fractions
(f_LC/f_1500) of 25% or more. This will be the first
measurement
of the escape fraction in sources between z=1 and the local
universe.
We expect ~10 detections. Stacking will set limits of <4% on
the
relative escape fraction in the rest. We will correlate the LC
detections
with the properties of the galaxies. By targeting z~0.7 in
COSMOS,
we will have tremendous ancillary information on those sources.
A
non-detection in all sources would be significant (99% confidence).
This
would imply that QSOs provide the overwhelming majority of ionizing
radiation
at z<1, requiring substantial evolution in the processes within
Lyman
break galaxies which allow large escape fractions at high
redshift.
WFPC2
11083
The
Structure, Formation and Evolution of Galactic Cores and Nuclei
A
surprising result has emerged from the ACS Virgo Cluster Survey
{ACSVCS},
a program to obtain ACS/WFC gz imaging for a large, unbiased
sample
of 100 early-type galaxies in the Virgo Cluster. On subarcsecond
scales
{i.e., <0.1"-1"}, the HST brightness profiles vary systematically
from
the brightest giants {which have nearly constant surface brightness
cores}
to the faintest dwarfs {which have compact stellar nuclei}.
Remarkably,
the fraction of galaxy mass contributed by the nuclei in the
faint
galaxies is identical to that contributed by supermassive black
holes
in the bright galaxies {0.2%}. These findings strongly suggest
that
a single mechanism is responsible for both types of Central Massive
Object:
most likely internally or externally modulated gas inflows that
feed
central black holes or lead to the formation of "nuclear star
clusters".
Understanding the history of gas accretion, star formation
and
chemical enrichment on subarcsecond scales has thus emerged as the
single
most pressing question in the study of nearby galactic nuclei,
either
active or quiescent. We propose an ambitious HST program {199
orbits}
that constitutes the next, obvious step forward:
high-resolution,
ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W}
imaging
for the complete ACSVCS sample. By capitalizing on HST's unique
ability
to provide high-resolution images with a sharp and stable PSF at
UV
and IR wavelengths, we will leverage the existing optical HST data to
obtain
the most complete picture currently possible for the history of
star
formation and chemical enrichment on these small scales. Equally
important,
this program will lead to a significant improvement in the
measured
structural parameters and density distributions for the stellar
nuclei
and the underlying galaxies, and provide a sensitive measure of
"frosting"
by young stars in the galaxy cores. By virtue of its superb
image
quality and stable PSF, NICMOS is the sole instrument capable of
the
IR observations proposed here. In the case of the WFPC2
observations,
high-resolution UV imaging {< 0.1"} is a capability unique
to
HST, yet one that could be lost at any time.
WFPC2
11291
Following
Eta Carinae's Change of State
Eta
Carinae is now known to be undergoing some unusually rapid changes
on
a timescale of several years. They are probably essential for
modeling
the star's long-term recovery from its Giant Eruption 160 years
ago
-- the prototype "supernova impostor" event. Since high spatial
resolution
is needed to isolate the central star, and the present state
will
probably not recur in the future, it is important to obtain HST
data
during the next two years. We propose a cost- effective set of ACS
observations
with three goals: {1} to obtain a continuing record of the
star's
rapid UV and visual brightening; {2} to lengthen the temporal
baseline
of ACS images enough to settle an important question concerning
ejecta
ages; and {3} to extend the record of morphological changes in
the
inner ejecta past the midpoint of eta Car's 5.5-year cycle.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
11190
- REacq(2,1,2) failed to RGA Hold (Gyro Control)
REacq(2,1,2) scheduled at 046/02:00:24 - 02:08:29 failed to RGA Hold due
to (QF2STOPF) stop flag indication on FGS2. Pre-acq OBADs had (RSS)
values of 858.68 and 9.83 arcseconds. Post-acq OBAD/MAP was not
scheduled. Received ACS 779 Status Buffer Messages ("Fold Mechanism Move
was Blocked") following the failure of the REacq.
COMPLETED
OPS REQUEST:
18207-0
- 32Kbps Memory Dump @ 045/1419z
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSacq 08 08
FGS
REacq 07 06
OBAD
with Maneuver 30 30
SIGNIFICANT
EVENTS:
Flash
Report : 32Kbps Memory Dump
Ops
Request #18207 was successfully executed to collect 32Kbps memory
dump
and verified that White Sands can handle the "J" (32Kbps memory
dump)
format correctly.