Daily Report # 4370

Notice: For the foreseeable future, the daily reports may contain apparent
discrepancies between some proposal descriptions and the listed instrument
usage. This is due to the conversion of previously approved ACS WFC or HRC
observations into WFPC2, or NICMOS observations subsequent to the loss of
ACS CCD science capability in late January.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4370

PERIOD COVERED: UT May 24, 2007 (DOY 144)

OBSERVATIONS SCHEDULED

WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for
supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS},
have found hundreds of SNe, many of them in quite nearby galaxies {cz 4000
km/s}. Most of the objects were discovered before maximum brightness, and
have follow-up photometry and spectroscopy; they include some of the
best-studied SNe to date. We propose to conduct a snapshot imaging survey of
the sites of some of these nearby objects, to obtain late-time photometry
that {through the shape of the light and color curves} will help reveal the
origin of their lingering energy. The images will also provide
high-resolution information on the local environments of SNe that are far
superior to what we can procure from the ground. For example, we will obtain
color-color and color-magnitude diagrams of stars in these SN sites, to
determine the SN progenitor masses and constraints on the reddening.
Recovery of the SNe in the new HST images will also allow us to actually
pinpoint their progenitor stars in cases where pre- explosion images exist
in the HST archive. This proposal is an extension of our successful Cycle 13
snapshot survey with ACS. It is complementary to our Cycle 15 archival
proposal, which is a continuation of our long-standing program to use
existing HST images to glean information about SN environments.

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}.

WFPC2 10826

Galaxy Evolution During Half the Age of the Universe: ACS imaging of rich
galaxy clusters

Detailed studies of nearby galaxies {z0.05} show that galaxies have very
complex histories of formation and evolution involving mergers, bursts of
star formation, and morphological changes. Even so, the global properties of
the galaxies {radii, luminosities, rotation velocities, velocity
dispersions, and absorption line strengths} follow a number of very tight
{empirical} scaling relations, e.g. the Tully-Fisher relation and the
Fundamental Plane {FP}. We use the scaling relations plus quantative
morphological measures for galaxy clusters up to z=1 to constrain models for
galaxy evolution. Here we request 24 orbits to obtain ACS imaging of the
remaining three clusters in our sample at z~0.7-1.0. High resolution imaging
of the clusters is critical for our study of star formation histories and
structural evolution in dense environments since z1. We have previously
obtained deep spectroscopic observations of the clusters with Gemini. The
data will provide samples large enough to establish the slope of the FP for
each cluster. With multiple clusters at similar redshifts, we can probe
evolutionary differences within a single epoch in order to decouple changes
due to different environments. Our two other high-z clusters exhibit
different chemical enrichment histories, which we argue are due to the
different merging histories of these clusters.

NIC2 10858

NICMOS Imaging of the z ~ 2 Spitzer Spectroscopic Sample of Ultraluminous
Infrared Galaxies

We propose to obtain NICMOS images of the first large sample of high-z
ultra-luminous infrared galaxies {ULIRGs} whose redshifts and physical
states have been determined with Spitzer mid-IR spectra. The detection of
strong silicate absorption and/or PAH emission lines suggest that the these
sources are a mixture of highly obscured starbursts, AGNs and composite
systems at z=2. Although some of the spectra show PAH emission similar to
local starburst ULIRGs, their bolometric luminosities are roughly an order
of magnitude higher. One important question is if major mergers, which are
the trigger for 95% of local ULIRGs, also drive this enormous energy output
observed in our z=2 sample. The NICMOS images will allow us to {1} measure
surface brightness profiles of z~2 ULIRGs and establish if major mergers
could be common among our luminous sources at these early epochs, {2}
determine if starbursts and AGNs classified based on their mid-IR spetra
would have different morphological signatures, thus different dynamic state;
{3} make comparisons with the similar studies of ULIRGs at z ~ 0 - 1, thus
infer any evolutionary connections between high-z ULIRGs and the formation
of normal, massive galaxies and quasars observed today.

WFPC2 10886

The Sloan Lens ACS Survey: Towards 100 New Strong Lenses

As a continuation of the highly successful Sloan Lens ACS {SLACS} Survey for
new strong gravitational lenses, we propose one orbit of ACS-WFC F814W
imaging for each of 50 high-probability strong galaxy-galaxy lens
candidates. These observations will confirm new lens systems and permit
immediate and accurate photometry, shape measurement, and mass modeling of
the lens galaxies. The lenses delivered by the SLACS Survey all show
extended source structure, furnishing more constraints on the projected lens
potential than lensed-quasar image positions. In addition, SLACS lenses have
lens galaxies that are much brighter than their lensed sources, facilitating
detailed photometric and dynamical observation of the former. When confirmed
lenses from this proposal are combined with lenses discovered by SLACS in
Cycles 13 and 14, we expect the final SLACS lens sample to number 80--100:
an approximate doubling of the number of known galaxy-scale strong
gravitational lenses and an order-of-magnitude increase in the number of
optical Einstein rings. By virtue of its homogeneous selection and sheer
size, the SLACS sample will allow an unprecedented exploration of the mass
structure of the early- type galaxy population as a function of all other
observable quantities. This new sample will be a valuable resource to the
astronomical community by enabling qualitatively new strong lensing science,
and as such we will waive all but a short {3-month} proprietary period on
the observations.

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.

WFPC2 10888

Complexity in the Smallest Galaxies: Star Formation History of the Sculptor
Dwarf Spheroidal

The Sculptor dwarf spheroidal galaxy {Scl dSph} is one of the most luminous
of the Milky Way dSph satellites, suffers virtually no foreground confusion
or reddening because of its high galactic latitude, and is nearby at 80 kpc
from the Sun. It is of great interest to astronomy to understand the
detailed histories of dSph galaxies because they may be survivors of the
hierarchical merging process that created giant galaxies like our own.
Despite this, the age distribution of stars in Scl dSph remains remarkably
poorly constrained because of a dearth of high-quality color-magnitude
diagrams {CMDs} of its central regions. Scl dSph is known to be complex on
the basis of shallower photometry, radial velocity studies, and
investigations of the metallicity; however, the age range of significant
star-formation and the proportion of stars older and younger than 10 Gyr is
still completely unknown. The age of the centrally concentrated, metal-rich
population has never been measured. We propose to obtain deep optical images
of the core of Scl dSph with WFPC2 in order to measure the temporal
evolution of its star-formation rate over its entire lifetime. The ONLY way
to reliably measure the variation in star-formation rate on Gyr timescales
at ages of 10-13 Gyr is with photometry of a large number of stars at and
below the oldest main-sequence turnoffs to magnitudes of {B,I} = {25.1,
24.5}. Because of the high stellar density and resulting image crowding, it
is impossible to achieve the required level of photometric precision except
with diffraction-limited imaging. These data will permit the first reliable
measurement of the star-formation history of the main body of Scl dSph;
limited inferences from WFPC2 data in an outer field have been made, but
they were hindered not only by small number statistics but by the subsequent
revelation of extremely strong population gradients in Scl dSph, such that
the stars in the existing WFPC2 field are not representative of the galaxy
as a whole. Our proposed program will shed strong new light on the formation
processes of the smallest galaxies. Only by measuring the detailed early
histories of galaxies like Scl dSph can we evaluate the impact of outside
influences like ram-pressure stripping, tidal stirring, and photoionization
feedback on the evolution of small galaxies.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.)

HSTARS:

10831 - REacq(1,2,1) failed due to search radius limit exceeded.

REacq(1,2,1) scheduled at 144/12:05:59 failed due to search radius limit
exceeded on FGS 1. OBAD1 showed errors of V1=-26.92, V2=-1645.61, V3=-27.15,
and RSS=1646.06. OBAD2 showed errors of V1=-55.09, V2=-29.53, V3=-55.84, and
RSS=83.81.

COMPLETED OPS REQUEST: (None)

18093-2 - PCS KF OOT Support, 144/13:17 @ 144/13:26z
18090-0 - MSS/CSS Initialization Test#9 for day 144 @ 144/13:52z

COMPLETED OPS NOTES: (None)

SIGNIFICANT EVENTS:

Evaluation of Universal Kalman Filter performance continued Details follow.

Background Kalman Filter Operation:

The KF was halted at 144/13:19. The filter was restarted at 144/13:25 with
the MSS and CSS sensor inputs enabled. The filter was restarted during a
vehicle slew and just prior to EON (13:27) to monitor how the penumbra would
effect convergence performance (M_C_IVP, Test #9). Only a short period of
UKF converged was able to be monitored due to the scheduled loss of return
telemetry shortly after EON (data was captured to the recorder). Subsequent
UKF performance was nominal. The filter was halted, reconfigured and
restarted with only the MSS sensor input enabled at 144/13:52.

This test completes the KF convergence testing for the 141 SMS. The filter
will be reconfigured to perform a long-term monitoring test of MSS and Gyro1
sensor input (CSS disabled) on Friday due to the few opportunities to
perform the remaining KF convergence testing in the 148 SMS.