Daily # 4138

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4138

PERIOD COVERED: UT June 19, 2006 (DOY 170)

OBSERVATIONS SCHEDULED

ACS/HRC 10512

Search for Binaries Among Faint Jupiter Trojan Asteroids

We propose an ambitious SNAPSHOT program to survey faint Jupiter
Trojan asteroids for binary companions. We target 150 objects, with
the expectation of acquiring data on about 50%. These objects span
Vmag = 17.5-19.5, a range inaccessible with ground-based adaptive
optics. We now have a significant sample from our survey of brighter
Trojans to suggest that the binary fraction is similar to that which
we find among brighter main-belt asteroids, roughly 2%. However, our
observations suggest a higher binary fraction for smaller main-belt
asteroids, probably the result of a different formation mechanism
{evident also from the physical characteristics of the binaries}.
Because the collision environment among the Trojans is similar to that
of the Main Belt, while the composition is likely to be very
different, sampling the binary fraction among the fainter Trojans
should help us understand the collisional and binary formation
mechanisms at work in various populations, including the Kuiper Belt,
and help us evaluate theories for the origin of the Trojans.
Calibration of and constraints on models of binary production and
collisional evolution can only be done using these large-scale,
real-life physical systems that we are beginning now to find and
utilize.

ACS/HRC 10738

Earth Flats

Sky flats will be obtained by observing the bright Earth with the HRC
and WFC. These observations will be used to verify the accuracy of the
flats currently in the pipeline and to monitor any changes. Weekly
coronagraphic monitoring is required to assess the changing position
of the spots.

ACS/HRC/WFC 10514

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 a
Snapshot program using the ACS/HRC that has a potential discovery
efficiency an order of magnitude higher than the HST observations that
have already discovered the majority of known transneptunian binaries.
By more than doubling the number of observed objects in dynamically
hot and cold subpopulations we will be able to answer, with
statistical significance, the question of whether these groups differ
in the abundance of binaries as a result 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/WFC 10758

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS. Changes from cycle 13:- The default
gain for WFC is 2 e-/DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period May, 31 2006- Oct, 1-2006. The
first half of the program has a different proposal number: 10729.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily pre-
scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.

ACS/WFC 10629

Are Field OB Stars Alone?

This SNAP program offers an inexpensive, simple program to search for
low-mass companions of field OB stars. Do field OB stars exist in true
isolation, as suggested by a recent Galactic study, or are they the
tip of the iceberg on a small cluster of low-mass stars as predicted
by the cluster mass function and stellar IMF? Short ACS/WFC V and I
observations proposed here may easily resolve this issue for field OB
stars in the Small Magellanic Cloud. Truly isolated OB stars represent
a theoretical challenge and variation from clusters, in mode of star
formation, and have important consequences for our understanding of
the field stellar population in galaxies. Small clusters around the
field OB stars, on the other hand, may confirm the universality of the
stellar clustering law and IMF.

ACS/WFC/NIC3 10632

Searching for galaxies at z6.5 in the Hubble Ultra Deep Field

We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the
area of the original Hubble Ultra Deep Field NICMOS parallel fields
and - through simultaneous parallel observations - deep NICMOS {F110W,
F160W} imaging of the ACS UDF area. Matching the extreme imaging depth
in the optical and near-IR bands will result in seven fields with
sufficiently sensitive multiband data to detect the expected typical
galaxies at z=7 and 8. Presently no such a field exist. Our combined
optical and near-IR ultradeep fields will be in three areas separated
by about 20 comoving Mpc at z=7. This will allow us to give a first
assessment of the degree of cosmic variance. If reionization is a
process extending over a large redshift interval and the luminosity
function doesn't evolve strongly beyond z=6, these data will allow us
to identify of the order of a dozen galaxies at 6.5z8.5 - using the
Lyman break technique - and to place a first constrain on the
luminosity function at z6.5. Conversely, finding fewer objects would
be an indication that the bulk of reionization is done by galaxies at
z=6. By spending 204 orbits of prime HST time we will capitalize on
the investment of 544 prime orbits already made on the Hubble Ultra
Deep Field {UDF}. We have verified that the program as proposed is
schedulable and that it will remain so even if forced to execute in
the 2-gyro mode. The data will be non-proprietary and the reduced
images will be made public within 2 months from the completion of the
observations.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration - CR Persistence Part 4

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 10748

WFPC2 CYCLE 14 Standard Darks

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10319 -ACS Suspend (707 &715) @170/1715z

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 12 12
FGS REacq 04 04
OBAD with Maneuver 32 32

SIGNIFICANT EVENTS:

The ACS suspended at 170/17:15:25z. An Ops Briefing was held at 6 pm
on June 19,2006.

At 170/17:15:25 the ACS 715 and ACS 707 status buffer (STB) messages
were received indicating the ACS WFC CEB analog signal processing +15
and + 5 volt power supply voltages were out of limits high which
resulted in the ACS suspend. Detailed analysis of the event is
underway with a tiger team meeting planned for Tuesday.