Daily # 4204

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4204

PERIOD COVERED: UT September 21, 2006 (DOY 264)

OBSERVATIONS SCHEDULED

ACS/HRC 10547

A SNAP Program to Obtain Complete Wavelength Coverage of Interstellar
Extinction

We propose a SNAP program to obtain ACS/HRC spectra in the near-UV
{PR200L} and near-IR {G800L} for a set of main sequence B stars with
available IUE UV spectrophotometry, optical photometry, and 2MASS IR
photometry. Together with these existing data, the new observations
will provide complete photometric and spectrophotometric coverage from
1150 to 11000 A and enable us to produce complete extinction curves
from the far-UV to the near-IR, with well- determined values of R{V}.
The proposed set of 50 program sight lines includes the full range of
interstellar extinction curve types and a wide range of color
excesses. The new data will allow us to examine variability in the
near-UV through near-IR spectral regions, including the UV-optical
"knee" and the "Very Broad Structure." We will examine the response of
these features to different interstellar environments and their
relationship to other curve features. These are largely unexplored
aspects of extinction curves which will provide additional constraints
on the properties of interstellar grains. The curves will be derived
using stellar atmosphere models to represent the intrinsic spectral
energy distributions of the program stars, eliminating the need to
observe unreddened "standard stars." This approach virtually
eliminates "mismatch error", allowing us to derive extinction curves
with much higher precision than previously possible. In addition, the
new spectra will provide higher S/N data for the peak of the 2175 A
bump than previously available.

ACS/HRC 10556

Neutral Gas at Redshift z=0.5

Damped Lyman-alpha systems {DLAs} are used to track the bulk of the
neutral hydrogen gas in the Universe. Prior to HST UV spectroscopy,
they could only be studied from the ground at redshifts z1.65.
However, HST has now permitted us to discover 41 DLAs at z1.65 in our
previous surveys. Followup studies of these systems are providing a
wealth of information about the evolution of the neutral gas phase
component of the Universe. But one problem is that these 41
low-redshift systems are spread over a wide range of redshifts
spanning nearly 70% of the age of the Universe. Consequently, past
surveys for low-redshift DLAs have not been able to offer very good
precision in any small redshift regime. Here we propose an ACS-HRC-
PR200L spectroscopic survey in the redshift interval z=[0.37, 0.7]
which we estimate will permit us to discover another 41 DLAs. This
will not only allow us to double the number of low-redshift DLAs, but
it will also provide a relatively high-precision regime in the
low-redshift Universe that can be used to anchor evolutionary studies.
Fortunately DLAs have high absorption equivalent width, so
ACS-HRC-PR200L has high-enough resoultion to perform this proposed
MgII-selected DLA survey.

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.

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.

NIC2 10906

The Fundamental Plane of Massive Gas-Rich Mergers: II. The QUEST QSOs

We propose deep NICMOS H-band imaging of a carefully selected sample
of 23 local QSOs. This program is the last critical element of a
comprehensive investigation of the most luminous mergers in the nearby
universe, the ultraluminous infrared galaxies {ULIRGs} and the
quasars. This effort is called QUEST: Quasar / ULIRG Evolutionary
STudy. The high-resolution HST images of the QUEST QSOs will
complement an identical set of images on the ULIRG sample obtained
during Cycle 12, an extensive set of ground-based data that include
long-slit NIR spectra from a Large VLT Program, and a large set of
mid-infrared spectra from a Cycle 1 medium-size program with Spitzer.
This unique dataset will allow us to derive with unprecedented
precision structual, kinematic, and activity parameters for a large
unbiased sample of objects spanning the entire ULIRG/QSO luminosity
function. These data will refine the fundamental plane of massive
gas-rich mergers and enable us to answer the following quesitons: {1}
Do ultraluminous mergers form elliptical galaxies, and in particular,
giant ellipticals? {2} Do ULIRGs evolve into optical bright QSOs? The
results from this detailed study of massive mergers in the local
universe will be relevant to understanding the basic physical
processes involved in creating massive early-type host on the one
hand, and growing/feeding embedded massive black holes on the other,
in major galaxy mergers. This is an important question since 50% of
cosmic star formation at high-z and most of the big BHs appear to be
formed in this process.

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.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and
highly non-uniform archive, making comprehensive comparative studies
among galaxies essentially impossible. We propose to secure HST's
lasting impact on the study of nearby galaxies by undertaking a
systematic, complete, and carefully crafted imaging survey of ALL
galaxies in the Local Universe outside the Local Group. The resulting
images will allow unprecedented measurements of: {1} the star
formation history {SFH} of a 100 Mpc^3 volume of the Universe with a
time resolution of Delta[log{t}]=0.25; {2} correlations between
spatially resolved SFHs and environment; {3} the structure and
properties of thick disks and stellar halos; and {4} the color
distributions, sizes, and specific frequencies of globular and disk
clusters as a function of galaxy mass and environment. To reach these
goals, we will use a combination of wide-field tiling and pointed deep
imaging to obtain uniform data on all 72 galaxies within a
volume-limited sample extending to ~3.5 Mpc, with an extension to the
M81 group. For each galaxy, the wide-field imaging will cover out to
~1.5 times the optical radius and will reach photometric depths of at
least 2 magnitudes below the tip of the red giant branch throughout
the limits of the survey volume. One additional deep pointing per
galaxy will reach SNR~10 for red clump stars, sufficient to recover
the ancient SFH from the color-magnitude diagram. This proposal will
produce photometric information for ~100 million stars {comparable to
the number in the SDSS survey} and uniform multi-color images of half
a square degree of sky. The resulting archive will establish the
fundamental optical database for nearby galaxies, in preparation for
the shift of high-resolution imaging to the near-infrared.

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:
17926-0 - Eclipse Management, GMT Day 265 (In progress. Last step
executed = step 4
17922-1 - Patch SOC1 and SOC2 Safing Limits in support of DOY 265 Solar
Eclipse event

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 05 05
FGS REacq 09 09
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS: (None)