Daily # 4286

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4286

PERIOD COVERED: UT January 25, 2007 (DOY 025)

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 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.

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 Type Ia supernovae at
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 Type Ia supernovae with NICMOS, reducing the
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 Type Ia supernovae at z 1. Together,
these 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 10861

An ACS Treasury Survey of the Coma cluster of galaxies

We propose to use the unique spatial resolution of HST and ACS to
construct a Treasury imaging survey of the core and infall region of
the richest local cluster, Coma. We will observe samples of thousands
of galaxies down to magnitude B=27.3 with the aim of studying in
detail the dwarf galaxy population which, according to hierarchical
models of galaxy formation, are the earliest galaxies to form in the
universe. Our initial scientific objectives a 1} A study of the
structure of the dwarf galaxies, including scaling laws, nuclear
structure and morphology, to compare with hierarchical and
evolutionary models of their formation. 2} A study of the stellar
populations from colors and color gradients, and how the internal
chemical evolution of galaxies is affected by interaction with the
cluster gaseous and galaxy environment. 3} To determine the effect of
the cluster environment upon morphological features, disks, bulges and
bars, by comparing these structure in the Coma sample with field
galaxy samples. 4} Identification of dwarf galaxy samples for further
study with the new generation of multi-object and integral-field
spectrographs on 8-10 metre class telescopes such as Keck, Subaru,
Gemini, and GTC. This is the first such survey of a nearby rich
cluster. It will provide a key database for studies of galaxy
formation and evolution, and a very needed reference for comparison
with similar galaxy surveys both in lower density environments in the
nearby universe, and in high density environments at high redshifts.

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 08 08
FGS REacq 07 07
OBAD with Maneuver 30 30

SIGNIFICANT EVENTS: (None)