Daily Report #4163

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4163

PERIOD COVERED: UT July 25, 2006 (DOY 206)

OBSERVATIONS SCHEDULED

ACS/HRC 10800

Kuiper Belt Binaries: Probes of Early Solar System Evolution

Binaries in the Kuiper Belt are a scientific windfall: in them we have
relatively fragile test particles which can be used as tracers of the
early dynamical evolution of the outer Solar System. We propose to
continue a Snapshot program using the ACS/HRC that has a demonstrated
discovery potential an order of magnitude higher than the HST
observations that have already discovered the majority of known
transneptunian binaries. With this continuation we seek to reach the
original goals of this project: to accumulate a sufficiently large
sample in each of the distinct populations collected in the Kuiper
Belt to be able to measure, with statistical significance, how the
fraction of binaries varies as a function of their particular
dynamical paths into the Kuiper Belt. Today's Kuiper Belt bears the
imprints of the final stages of giant-planet building and migration;
binaries may offer some of the best preserved evidence of that
long-ago era.

ACS/HRC 10805

ACS Imaging of Uranus' Atmosphere Near Equinox

Uranus' 97-degree spin axis inclination results in the largest
fractional seasonal variation of solar insolation in the solar system.
Uranus is now close to its 7 December 2007 equinox, and we can now see
most of the northern hemisphere, which was in darkness when Voyager
provided our first detailed view of the planet in 1986. If Uranus'
seasonal response has the large phase shift expected from its long
radiative time constant, it should now exhibit nearly maximal
hemispheric contrast. Although the long time constant also suggests a
small physical response, significant hemispheric asymmetries in cloud
structure and dynamics are becoming apparent. We propose a detailed
characterization of Uranus' current response to this forcing with a
10-orbit program consisting of 4 orbits of WFC imaging with narrowband
ramp filters and 6 orbits of HRC imaging using both broadband and
narrowband filters. Nine narrow-band filters between 0.62 and 0.955
microns will provide vertical sensing depths scanning through the
pressure range where the putative methane and deeper H2S clouds might
plausibly exist and provide strong constraints on their optical
properties and parent gas mixing ratios. The high resolution HRC
images will characterize the dynamics of discrete features at the
15-30 hour time scale unavailable from the ground. Short wavelength
HRC images will enable a characterization of the stratospheric haze.
These observations have unique combinations of spectral range and
resolution with needed temporal and spatial resolution not available
from groundbased observations.

ACS/WFC 10258

Tracing the Emergence of the Hubble Sequence Among the Most Luminous
and Massive Galaxies

There is mounting evidence that the redshift range 1 z 2 was an
important era when massive galaxies assembled their stellar content
and assumed their present--day morphologies. Despite extensive HST
imaging surveys, however, there is very little data in the optical
rest frame {i.e., observed near--infrared} on the morphologies of the
most luminous galaxies at these redshifts. We propose to image a
carefully selected set of 20 of the most luminous, K--band selected
GOODS galaxies at 1.3 z 2, using NICMOS camera 2. This offers
diffraction--limited, critically sampled imaging at 1.6 microns to
ensure the best angular resolution for comparison to ACS. The galaxies
are chosen to span a simple 4--fold parameter space of morphological
and spectral type, in order to provide the most information about the
variety of massive galaxy properties in this redshift range. We will
investigate the emergence of large scale--length disks, stable spiral
structure, mature bulges with red stellar populations, central bar
structures, the incidence of disturbed morphology, the existence {or
lack thereof} of blue ellipticals, and other questions that concern
the evolution and maturation of the brightest, largest, and most
massive ordinary galaxies in this critical redshift range.

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 10849

Imaging Scattered Light from Debris Disks Discovered by the Spitzer
Space Telescope around 21 Sun-like Stars

We propose to use the high-contrast capability of the NICMOS
coronagraph to image a sample of newly discovered circumstellar disks
associated with Sun-like stars. These systems were identified by their
strong thermal infrared {IR} emission with the Spitzer Space Telescope
as part of the Spitzer Legacy Science program titled "The Formation
and Evolution of Planetary Systems" {FEPS, P.I.: M.Meyer}. Modeling of
the thermal excess emission from the spectral energy distributions
alone cannot distinguish between narrowly confined high-opacity disks
and broadly distributed, low-opacity disks. By resolving light
scattered by the circumstellar material, our proposed NICMOS
observations can break this degeneracy, thus revealing the conditions
under which planet formation processes are occuring or have occured.
For three of our IR-excess stars that have known radial-velocity
planets, resolved imaging of the circumstellar debris disks may
further offer an unprecedented view of planet-disk interactions in an
extrasolar planetary system. Even non-detections of the light
scattered by the circumstellar material will place strong constraints
on the disk geometries, ruling out disk models with high optical
depth. Unlike previous disk imaging programs, our program contains a
well-defined sample of ~1 solar mass stars covering a range of ages
from 3 Myr to 3 Gyr, thus allowing us to study the evolution of disks
from primordial to debris for the first time. The results from our
program will greatly improve our understanding of the architecture of
debris disks around Sun-like stars, and will create a morphological
context for the existence of our own solar system. This proposal is
for a continuation of an approved Cycle 14 program {GO/10527, P.I.: D.
Hines}.

WFPC2 10745

WFPC2 CYCLE 14 INTERNAL MONITOR

This calibration proposal is the Cycle 14 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{both gain 7 and gain 15 -- to test stability of gains and bias
levels}, a test for quantum efficiency in the CCDs, and a monitor for
possible buildup of contaminants on the CCD windows. These also
provide raw data for generating annual super-bias reference files for
the calibration pipeline.


FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

#10372 GSAcq (2,1,1) failed due to Scan Step Limit Exceeded on FGS 2 @
206/13:38:46z

At 206/13:38:46 GSAc1 (2,1,1) failed to RGA hold due to scan step
limit exceeded on FGS 2. OBADs RSS values were 3737.64 & 13.54
respectively. Possible observations affected: ACS 56. OBAD MAP
scheduled @ 206/14:44:43 showed the following errors: V1 -820.84, V2
5011.53, V3 -451.42, RSS 5098.34

#10373 GSAcq (2,3,2) failed due to search radius limit exceeded on FGS
2 @ 206/17:00:47z

At AOS 206/17:00:47, GSAcq (2,3,2) had failed due to search radius
limit exceeded on FGS 2. OBAD #1 data unavailable due to LOS. OBAD #2
V1 43.70, V2 31.93, V3 52.14, RSS 75.15. Possible observations
affected: ACS 59

#10374 GSAcq(2,1,2) failed due to search radius limit exceeded @
207/01:14:20z.

The GSAcq(2,1,2) failed due to search radius limit exceeded on FGS 2.
OBAD2 showed errors of V1=-2.03, V2=-3.48, V3=3.24, RSS=5.15. The Map
at 01:16:44 showed errors of V1=1.43, V2=2.84, V3=-0.02, and RSS=3.18.
Observations affected: ACS 73-79, NIC 21 and 22

#10375 GSAcq(2,1,2) failed to RGA Control @ 07:20:02z

The GSAcq(2,1,2) failed to RGA Hold due to search radius limit
exceeded on FGS-2. Pre-acquisition OBADs had (RSS) attitude erorr
corrections values of 2943.18 and 10.66 arcseconds. Post-acquisition
OBAD/MAP had 3-axis (RSS) value of 3.06 arcseconds. REacq(2,1,2)
scheduled at 207/08:46:00 using same star id failed to RGA Hold.
Observations affected: ACS 82,83.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES:
#1511-1 Reset NICMOS Error Counter @ 207/02:31z

SCHEDULED SUCCESSFUL
FGS GSacq 13 09
FGS REacq 02 01
OBAD with Maneuver 30 30

SIGNIFICANT EVENTS: (None)