HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT # 4305
PERIOD COVERED: UT February 22, 2007 (DOY 053)
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/WFC 10918
Reducing Systematic Errors on the Hubble Constant:
Metallicity
Calibration of the
Reducing the systematic errors on the Hubble constant is
still of
significance and of immediate importance to modern
cosmology. One of the
largest remaining uncertainties in the Cepheid-based
distance scale
{which itself is at the foundation of the HST Key Project
determination
of H_o} which can now be addressed directly by HST, is the
effect of
metallicity on the Cepheid Period-Luminosity relation.
Three chemically
distinct regions in M101 will be used to directly measure
and thereby
calibrate the change in zero point of the
range of metallicities that run from SMC-like, through
Solar, to
metallicities as high as the most metal-enriched galaxies
in the pure
Hubble flow. ACS for the first time offers the opportunity
to make a
precise calibration of this effect which currently
accounts for at least
a third of the total systematic uncertainty on Ho. The
calibration will
be made in the V and I bandpasses so as to be immediately
and directly
applicable to the entire HST Cepheid-based distance scale
sample, and
most especially to the highest-metallicity galaxies that
were hosts to
the Type Ia supernovae, which were then used to extend the
the distance
scale calibration out to cosmologically significant
distances.
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 10792
Quasars at Redshift z=6 and Early Star Formation History
We propose to observe four high-redshift quasars {z=6} in
the NIR in
order to estimate relative Fe/Mg abundances and the
central black hole
mass. The results of this study will critically constrain
models of
joint quasar and galaxy formation, early star formation,
and the growth
of supermassive black holes. Different time scales and
yields for
alpha-elements {like O or Mg} and for iron result into an
iron
enrichment delay of ~0.3 to 0.6 Gyr. Hence, despite the
well-known
complexity of the FeII emission line spectrum, the ratio
iron/alpha -
element is a potentially useful cosmological clock. The
central black
hole mass will be estimated based on a recently revised
back hole mass -
luminosity relationship. The time delay of the iron
enrichment and the
time required to form a supermassive black hole {logM>8
Msol, tau
~0.5Gyr} as evidenced by quasar activity will be used to
date the
beginning of the first intense star formation, marking the
formation of
the first massive galaxies that host luminous quasars, and
to constrain
the epoch when supermassive black holes start to grow by
accretion.
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 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.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
10708 - GSACQ(1,2,1) failed, Search Radius Limit Exceeded
on FGS 2
Upon acquisition of signal at
054:01:26:15 vehicle was in gyro control
with FGS 2 search radius limit
flag set. GSACQ(1,2,1) at 054:01:11:16
failed with search radius limit
exceeded. OBAD before GSACQ failure
showed RSS error correction of
12.61 arcseconds.
REACQ(1,2,1) at 02:47:11 also
failed with search radius limit exceeded
on FGS 2.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 11 10
FGS REacq 03 02
OBAD with Maneuver 28 28
SIGNIFICANT EVENTS: (None)