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 # 4339
PERIOD COVERED: UT April 11, 2007 (DOY 101)
OBSERVATIONS SCHEDULED
ACS/SBC 10872
Lyman Continuum Emission in Galaxies at z=1.2
Lyman continuum photons produced in massive starbursts may
have played a
dominant role in the reionization of the Universe.
Starbursts are
important contributors to the ionizing metagalactic
background at lower
redshifts as well. However, their contribution to the
background depends
upon the fraction of ionizing radiation that escapes from
the intrinsic
opacity of galaxies below the Lyman limit. Current surveys
suggest
escape fractions of a few percent, up to 10%, with very
few detections
{as opposed to upper limits} having been reported. No
detections have
been reported in the epochs between z=0.1 and z=2. We
propose to measure
the fraction of escaping Lyman continuum radiation from 15
luminous
z~1.2 galaxies in the GOODS fields. Using the tremendous
sensitivity of
the ACS Solar- blind Channel, we will reach AB=30 mag.,
allowing us to
detect an escape fraction of 1%. We will correlate the
amount of
escaping radiation with the photometric and morphological
properties of
the galaxies. A non-detection in all sources would imply
that QSOs
provide the overwhelming majority of ionizing radiation at
z=1.3, and it
would strongly indicate that the properties of galaxies at
higher
redshift have to be significantly different for galaxies
to dominate
reionization. The deep FUV images will also be useful for
extending the
FUV study of other galaxies in the GOODS fields.
WFPC2 10166
ACS and WFPC2 Stellar Photometry in the Kepler Mission Target
Field
We will observe three regions at the Galactic Equator {GE}
to determine
the number of stars in the magnitude range from 18 to 25
in the target
field of the NASA Kepler mission. This mission will search
for
Earth-size planets orbiting other stars. The field is a
twelve by twelve
degree square in Cygnus. It abuts the GE. The detection
technique is to
search photometrically for planetary transits. Faint
eclipsing binaries
that are not spatially resolved from the target star by
Kepler may cause
confusion, leading to false positive detections. The HST
is uniquely
capable of determining the potential magnitude of the
issue in the
region of the GE, where stellar densities are extremely
high.
NIC1 11057
Cycle 15 NICMOS dark current, shading profile, and read
noise monitoring
program
The purpose of this proposal is to monitor the dark
current, read noise,
and shading profile for all three NICMOS detectors
throughout the
duration of Cycle 15. This proposal is a slightly modified
version of
proposal 10380 of cycle 13 and 9993 of cycle12 and is the
same as Cycle
14. that we cut down some exposure time to make the
observation fit
within 24 orbits.
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA calibration - CR Persistence Part 6
A new proceedure proposed to alleviate the CR-persistence
problem of
NICMOS. Dark frames will be obtained immediately upon
exiting the SAA
contour 23, and everytime 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 i
mages. Each observation will need its own CRMAP, as different
SAA
passages leave different imprints on the NICMOS detectors.
NIC3 10839
The NICMOS Polarimetric Calibration
Recently, it has been shown that NICMOS possesses an
instrumental
polarization at a level of 1.2%. This completely inhibits
the data
reduction in a number of previous GO programs, and hampers
the ability
of the instrument to perform high accuracy polarimetry. In
all, 90
orbits of HST data are affected, with potentially many
more in Cycle 15.
We propose to obtain high signal to noise observations of
three
polarimetric standards at the cardinal roll angles of the
NICMOS
polarizers for both NIC1 and NIC2. These observations are
designed to
fully characterize the instrumental polarization in order
for NICMOS to
reach its full potential by enabling high accuracy
polarimetry of
sources with polarizations around 1%. The residual
polarization will
also be determined as a function of position and spectral
energy
distribution. Our group will rapidly turn around the
required data
products and produce reports and software for the accurate
representation of the instrumental polarization. These
items will be
presented to STScI and for dissemination among the wider
astronomical
community.
WFPC2 11031
CTE Background Dependence Closeout
Measuring the charge transfer efficiency {CTE} of an
astronomical CCD
camera is crucial to determining the CCD's photometric
fidelity across
the field of view. WFPC2's CTE has degraded steadily over
the last 13
years because of continuous exposure to trapped particles
in HST's
radiation environment. The fraction of photometric signal
lost from
WFPC2's CTI {charge transfer inefficiency} is a function
of WFPC2's time
in orbit, the integrated signal in the image, the location
of the image
on the CCD, and the background signal. Routine monitoring
of WFPC2's CTE
over the last 13 years permits an assessment of all but
the last
condition. The dependence of CTE on background signal must
be
characterized, however, because a large fraction of WFPC2
images have
been obtained under conditions of significant sky
background. This
program aims to assess the end-of-life CTE of WFPC2's CCDs
separately as
a function of background signal. Traditional images of an
off-center
field in NGC 5139 {Omega Cen} are recorded after
preflashing {or before
postflashing} the CCDs with internal lamps to provide
average background
signals of 0-160 e-, which span the range of sky
backgrounds observed in
~99% of long-exposure narrow- and broad-band WFPC2 images.
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
08
08
FGS REacq
04
04
OBAD with Maneuver
22
22
SIGNIFICANT EVENTS: (None)