Daily # 4305

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 Cepheid PL Relation

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 Cepheid
PL relation over a 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 q0.25
at separations exceeding ~3 AU, while probing companions with q0.5 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 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 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 {logM8 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)