HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

 

DAILY REPORT    # 4314

 

PERIOD COVERED: UT March 07, 2007 (DOY 066)

 

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 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 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.

 

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.

 

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              10                    10                  
FGS REacq               04                    04                  
OBAD with Maneuver 28                    28