Daily Report # 4416

Notice: Due to the conversion of some ACS WFC or HRC observations into
WFPC2, or NICMOS observations after the loss of ACS CCD science
capability in January, there may be an occasional discrepancy between
a proposal's listed (and correct) instrument usage and the abstract
that follows it.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4416

PERIOD COVERED: UT July 31, 2007 (DOY 212)

OBSERVATIONS SCHEDULED

WFPC2 11024

WFPC2 CYCLE 15 INTERNAL MONITOR

This calibration proposal is the Cycle 15 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.

NIC1/NIC2/NIC3 11060

NICMOS Photometric Stability Monitoring

This NICMOS calibration proposal carries out photometric monitoring
observations during Cycle 15. The format is the same as the Cycle 14
version of the program {10725}, but a few modifications were made with
respect to the Cycle 12 program 9995 and Cycle 13 program 10381.
Provisions had to be made to adopt to 2-gyro mode {G191B2B was added
as extra target to provide target visibility through most of the
year}. Where before 4 or 7 dithers were made in a filter before we
moved to the next filter, now we observe all filters at one position
before moving to the next dither position. While the previous method
was chosen to minimize the effect of persistence, we now realize that
persistence may be connected to charge trapping and by moving through
the filter such that the count rate increases, we reach equilibrium
more quickly between charge being trapped and released. We have also
increased exposure times where possible to reduce the charge trapping
non-linearity effects.

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 11023

WFPC2 CYCLE 15 Standard Darks - part 1

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.

WFPC2 11084

Probing the Least Luminous Galaxies in the Local Universe

We propose to obtain deep color-magnitude data of eight new Local
Group galaxies which we recently discovered: Andromeda XI, Andromeda
XII, and Andromeda XIII {satellites of M31}; Canes Venatici I, Canes
Venatici II, Hercules, and Leo IV {satellites of the Milky Way}; and
Leo T, a new "free-floating" Local Group dwarf spheroidal with
evidence for recent star formation and associated H I gas. These
represent the least luminous galaxies known at *any* redshift, and are
the only accessible laboratories for studying this extreme regime of
galaxy formation. With deep WFPC-2 F606W and F814W pointings at their
centers, we will determine whether these objects contain single or
multiple age stellar populations, as well as whether these objects
display a range of metallicities.

WFPC2/NIC3 11188

First Resolved Imaging of Escaping Lyman Continuum

The emission from star-forming galaxies appears to be responsible for
reionization of the universe at z6. However, the models that attempt
to describe the detailed impact of high- redshift galaxies on the
surrounding inter-galactic medium {IGM} are strongly dependent upon
several uncertain parameters. Perhaps the most uncertain is the
fraction of HI-ionizing photons produced by young stars which escape
into the IGM. Most attempts to measure this "escape fraction" {f_esc}
have produced null results. Recently, a small subset of z~3 Lyman
Break Galaxies {LBGs} has been found exhibiting large escape
fractions. It remains unclear however, what differentiates them from
other LBGs. Several models attempt to explain how such a large
fraction of ionizing continuum can escape through the HI and dust in
the ISM {eg. "chimneys" created by SNe winds, globular cluster
formation, etc.}, each producing unique signatures which can be
observed with resolved imaging of the escaping Lyman continuum. We
propose a deep, high resolution WFPC2 image of the ionizing continuum
{F336W} and the rest-frame 1500 Angstrom continuum {F606W} of five of
the six known LBGs with large escape fractions. These LBGs all fit
within a single WFPC2 pointing, yielding high observing efficiency.
Additionally, they all have z~3.1 or higher, the optimal redshift
range for probing the Lyman Continuum region with available WFPC2
filters. These factors make our proposed sample especially suitable
for follow- up. With these data we will discern the mechanisms
responsible for producing large escape fractions, and therefore gain
insight into the process of reionization.

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*************** 05***************** 05
FGS REacq*************** 08***************** 08
OBAD with Maneuver* **** 20***************** 20

SIGNIFICANT EVENTS: (None)