HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT # 4304
PERIOD COVERED: UT February 21, 2007 (DOY 052)
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}.
ACS/SBC 11056
Improved Sensitivity SBC Prisms
The flux calibration of the SBC {PR110L and PR130L} will
be improved by
observing for each prism white dwarf standards {WD1657+343
and LTT9491}.
The blue standard star WD1657+343 has previously been
observed with
ACS/SBC and will serve as a reference point to track time
dependent
variations. LTT9491 is much redder and thus will be used
to investigate
the sensitivity curve of ?red? targets to check for a
potential red leak
of the SBC. Additionally, LTT9491 shows various strong
absorption lines
which can be used to confirm the wavelength calibration of
the PR110L
and PR130L prisms. The standard stars are observed at a
variety of
pointings across the SBC detector in order to map spatial
variations.
LTT9491 will also be observed with ACS/HRC PR200L to
obtain an improved
flux calibration from about 1800 A to 4000 A.
ACS/WFC 10798
Dark Halos and Substructure from Arcs & Einstein Rings
The surface brightness distribution of extended
gravitationally lensed
arcs and Einstein rings contains super-resolved
information about the
lensed object, and, more excitingly, about the smooth and
clumpy mass
distribution of the lens galaxies. The source and lens
information can
non-parametrically be separated, resulting in a direct
"gravitational
image" of the inner mass-distribution of
cosmologically-distant galaxies
{Koopmans 2005; Koopmans et al. 2006 [astro-ph/0601628]}.
With this goal
in mind, we propose deep HST ACS-F555W/F814W and
NICMOS-F160W WFC
imaging of 20 new gravitational-lens systems with
spatially resolved
lensed sources, of the 35 new lens systems discovered by
the Sloan Lens
ACS Survey {Bolton et al. 2005} so far, 15 of which are
being imaged in
Cycle-14. Each system has been selected from the SDSS and
confirmed in
two time- efficient HST-ACS snapshot programs {cycle
13&14}.
High-fidelity multi-color HST images are required {not
delivered by the
420s snapshots} to isolate these lensed images {properly
cleaned,
dithered and extinction-corrected} from the lens galaxy
surface
brightness distribution, and apply our "gravitational
maging" technique.
Our sample of 35 early-type lens galaxies to date is by
far the largest,
still growing, and most uniformly selected. This minimizes
selection
biases and small-number statistics, compared to smaller,
often
serendipitously discovered, samples. Moreover, using the
WFC provides
information on the field around the lens, higher S/N and a
better
understood PSF, compared with the HRC, and one retains
high spatial
resolution through drizzling. The sample of galaxy mass
distributions -
determined through this method from the arcs and Einstein
ring HST
images - will be studied to: {i} measure the smooth mass
distribution of
the lens galaxies {dark and luminous mass are separated
using the HST
images and the stellar M/L values derived from a joint
stellar-dynamical
analysis of each system}; {ii} quantify statistically and
individually
the incidence of mass-substructure {with or without
obvious luminous
counter- parts such as dwarf galaxies}. Since dark-matter
substructure
could be more prevalent at higher redshift, both results
provide a
direct test of this prediction of the CDM hierarchical
structure-formation model.
FGS 10989
Astrometric Masses of Extrasolar Planets and Brown Dwarfs
We propose observations with HST/FGS to estimate the
astrometric
elements {perturbation orbit semi-major axis and
inclination} of
extra-solar planets orbiting six stars. These companions
were originally
detected by radial velocity techniques. We have
demonstrated that FGS
astrometry of even a short segment of reflex motion, when
combined with
extensive radial velocity information, can yield useful
inclination
information {McArthur et al. 2004}, allowing us to
determine companion
masses. Extrasolar planet masses assist in two ongoing
research
frontiers. First, they provide useful boundary conditions
for models of
planetary formation and evolution of planetary systems.
Second, knowing
that a star in fact has a plantary mass companion,
increases the value
of that system to future extrasolar planet observation
missions such as
SIM PlanetQuest, TPF, and GAIA.
NIC1 10879
A search for planetary-mass companions to the nearest L
dwarfs -
completing the survey
We propose to extend the most sensitive survey yet
undertaken for very
low-mass companions to ultracool dwarfs. We will use
NICMOS to complete
imaging of an all-sky sample of 87 L dwarfs in 80 systems
within 20
parsecs of the Sun. The combination of infrared imaging
and proximity
allows us to search for companions with mass ratios
q>0.25 at
separations exceeding ~3 AU, while probing companions with
q>0.5 at ~1.5
AU separation. This resolution is crucial, since no
ultracool binaries
are known in the field with separations exceeding 15 AU.
Fifty L dwarfs
from the 20-parsec sample have high- resolution imaging,
primarily
through our Cycle 13 HST proposal which identified six new
binaries,
including an L/T system. Here, we propose to target the
remaining 30
dwarfs
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.
NIC2, ACS/WFC 10802
SHOES-Supernovae, HO, for the Equation of State of Dark
energy
The present uncertainty in the value of the Hubble
constant {resulting
in an uncertainty in Omega_M} and the paucity of
redshifts exceeding 1 are now the leading obstacles to
determining the
nature of dark energy. We propose a single, integrated set
of
observations for Cycle 15 that will provide a 40%
improvement in
constraints on dark energy. This program will observe
known Cepheids in
six reliable hosts of
uncertainty in H_0 by a factor of two because of the
smaller dispersion
along the instability strip, the diminished extinction,
and the weaker
metallicity dependence in the infrared. In parallel with
ACS, at the
same time the NICMOS observations are underway, we will
discover and
follow a sample of
measurements, along with prior constraints from WMAP, will
provide a
great improvement in HST's ability to distinguish between
a static,
cosmological constant and dynamical dark energy. The
Hubble Space
Telescope is the only instrument in the world that can
make these IR
measurements of Cepheids beyond the Local Group, and it is
the only
telescope in the world that can be used to find and follow
supernovae at
z > 1. Our program exploits both of these unique
capabilities of HST to
learn more about one of the greatest mysteries in science.
NIC3 11080
Exploring the Scaling Laws of Star Formation
As a variety of surveys of the local and distant Universe
are
approaching a full census of galaxy populations, our
attention needs to
turn towards understanding and quantifying the physical
mechanisms that
trigger and regulate the large-scale star formation rates
{SFRs} in
galaxies.
WFPC2 10822
CIII] Imagery of Planetary Nebulae
We propose to image five planetary nebulae {PNe} with the
F185W filter
of WFPC2 in order to study the spatial distribution of the
ultraviolet C
III] 1909 Angstrom line relative to [O III] 5007 Angstrom
and other
optical lines. This program follows a Cycle 12 SNAP
program {GO 9740} of
WFPC2 F185W imaging of PNe and H II regions which
validated the
feasibility of obtaining images of bright PNe in C III]
through careful
continuum subtraction and calibrations based on archival
IUE SWP and
LWP/R spectra. However, in the SNAP program only short {10
minute}
exposures of four PNe were taken; we now propose much
longer exposures
{60-72 minutes} to obtain the desired signal-to-noise to
develop high
quality C++ ionization maps for comparison with O++ and
other ions via
photoionization modeling. The five PNe chosen: NGC 2392,
NGC 3242, NGC
6543, NGC 6720, and NGC 7662 were selected on the basis of
their high
surface brightness, extensive UV spectra available from
IUE and HST, and
numerous WFPC2 images in the archives in other emission
lines. We expect
the results of this study to impact the utility and
accuracy of using
the C III] 1909 lines compared to [O III] 5007 for C/O
abundance
derivations in PNe and H II regions.
WFPC2 10871
Observations of the Galilean Satellites in Support of the
New Horizons
Flyby
On February 28 2007 the New Horizons {NH} spacecraft will
fly by Jupiter
on its way to Pluto, and will conduct an extensive series
of
observations of the Jupiter system, including the Galilean
satellites.
We propose HST observations to support and complement the
New Horizons
observations in four ways: 1} Determine the distribution
and variability
of Io's plumes in the two weeks before NH closest
approach, to look for
correlations with Io- derived dust streams that may be
detected by New
Horizons, to understand the origin of the dust streams; 2}
Imaging of
SO2 and S2 gas absorption in Io's plumes in Jupiter
transit, which
cannot be done by NH; 3} Color imaging of Io's surface to
determine the
effects of the plumes and volcanos seen by New Horizons on
the surface-
New Horizons cannot image the sunlit surface in color due
to saturation;
4} Imaging of far-UV auroral emissions from the
atmospheres of Io,
Europa, and Ganymede in Jupiter eclipse, near-
simultaneously with
disk-integrated NH UV spectra, to locate the source of the
UV emissions
seen by NH and use the response of the satellite
atmospheres to the
eclipse to constrain production mechanisms.
WFPC2 11092
Hubble Heritage Observations of Arp 87
The Hubble Heritage team will use a single pointing of
WFPC2 to obtain
F450W, F555W, F656N, and F814W images of Arp 87 as part of
a public
release image.
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: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 11 11
FGS REacq 03 03
OBAD with Maneuver 28 28
SIGNIFICANT EVENTS: (None)