Daily Report #4483

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****** # 4483

PERIOD COVERED: UT November 05, 2007 (DOY 309)

OBSERVATIONS SCHEDULED

ACS/SBC 11215

New Sightlines for the Study of Intergalactic Helium: Dozens of
High-Confidence, UV- Bright Quasars from SDSS/GALEX

The reionization of IGM helium is thought to have occurred at
redshifts of z=3 to 4. Detailed study of HeII Lyman-alpha absorption
toward a handful of QSOs at 2.7z3.3 demonstrated the high potential
of such IGM probes, but the critically small sample size limits
confidence in cosmological inferences. The requisite unobscured
sightlines to high-z are extremely rare, but SDSS provides 5800, z3.1
QSOs potentially suitable for HeII studies. We've cross-correlated
SDSS quasars with GALEX UV sources to obtain dozens of new, high
confidence, candidate sightlines {z=3.1-4.9} potentially useful for
detailed HeII studies with HST. We propose brief, 2-orbit
reconnaissance ACS SBC prism exposures toward each of the best dozen
new quasars, to definitively verify UV flux down to HeII. Our combined
SDSS/GALEX selection insures a high confirmation rate, as the quasars
are already known to be UV bright in GALEX. Our program will provide a
statistical sample of HeII sightlines extending to high redshift,
enabling future long exposure follow-up spectra with the SBC prism, or
superb quality COS or STIS spectra after SM4. Stacks of our prism
spectra will also directly yield ensemble information. Ultimately, the
new sightlines will enable confident measures of the spectrum and
evolution of the ionizing background, the evolution of HeII opacity,
the epoch of helium reionization, and the density of IGM baryons.

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.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is
seriously incomplete for systems in the period range from years to
millennia because the radial velocity variations are too small and the
angular separations too close for easy detection. Here we propose to
discover binaries in this observational gap through a Faint Guidance
Sensor SNAP survey of relatively bright targets listed in the Galactic
O Star Catalog. Our primary goal is to determine the binary frequency
among those in the cluster/association, field, and runaway groups. The
results will help us assess the role of binaries in massive star
formation and in the processes that lead to the ejection of massive
stars from their natal clusters. The program will also lead to the
identification of new, close binaries that will be targets of long
term spectroscopic and high angular resolution observations to
determine their masses and distances. The results will also be
important for the interpretation of the spectra of suspected and newly
identified binary and multiple systems.

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 DARKs. 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 11341

Lower Luminosity AGNs at Cosmologically Interesting Redshifts: SEDs
and Accretion Rates of z~0.36 Seyferts

We propose a multiwavelength campaign to constrain the SEDs of
Seyferts at z~0.36. This epoch, corresponding to a look back time of 4
Gyrs, is cosmologically interesting for studies of the coeval
development of black holes and their host galaxy bulges. Our sample,
comprising 24 Seyferts, has unprecedented high quality Keck
spectroscopy and HST imaging already invested to extract host galaxy
bulge properties, estimate black hole masses, and separate nuclear and
host optical luminosities. To supplement and extend this successful
program, we request 93 ks of Chandra time (to measure the shape and
power of the AGN-only X-ray continuum), 11 hrs each of Spitzer and
Gemini (to constrain the dust temperature), and 7 orbits of HST (to
determine the nuclear luminosity for the final 7 objects).

NIC3/WFPC2 10921

Tangential Velocities of Objects in the Orion Nebula and Locating the
Embedded Outflow Sources.

The Orion Nebula is arguably the Rosetta Stone for studying a very
young star cluster and how the radiation and outflowing plasma from
its stars interact with ambient material. It has been the subject of
numerous HST imaging studies, which means that there is good
opportunity for determining tangential velocities by obtaining second
epoch images during Cycle 15, which may be the last cycle for which
the WFPC2 is available. These velocities in the plane-of-the-sky will
allow us to determine the patterns of outflow from micro-jets smaller
than the Solar System to jet driven shocks more than a parsec from
their sources. Combined with radial velocities, we'll obtain spatial
velocities, which are critical to determining where the embedded
sources are located that produce the numerous HH objects coming from
the Orion-S and BN-KL regions. We'll also be able to determine the
physics that is operating in the LL Ori type of outflows {where a
bipolar jet is being distorted by a slow wind coming from the nebula}.
We will also be able to search for runaway stars caused by the
disintegration of young multiple-star systems. All of this is possible
because the long-time base of the WFPC2 and ACS observations allow a
new level of astrometric precision to be obtained and to be done
efficiently by making coordinated parallel observations with all
images.

WFPC2 10900

Optical polarimetry of PSR B0540-69 and its synchrotron nebula.

Polarization measurements of pulsars and of their synchrotron nebulae
are uniquely able to provide deep insights into the highly magnetized
relativistic environment of young rotating neutron stars. Apart from
the radio band, pulsar polarization is best measured in the optical,
for the rare cases of detectable optical emission. One of the
brightest pulsars together with Crab {PSR B0531+21} and Vela {PSR
B0833-45}, for which optical polarization measurements support the
newly developed two-pole caustic model {TPC}, is PSR B0540-69 in the
Large Magellanic Clouds, often referred as the Crab Twin for their
overall similarities in both age and energetics. Together with the
Crab, PSR B0540-69 is also the only pulsar embedded in a synchrotron
nebula visible at optical wavelengths. We plan to observe PSR B0540-69
and its compact nebula {4 arcsec diameter} with the Advanced Camera
for Surveys {ACS} and the Wide Field Channel {WFC} detector using UV
and visual polarization filters. Thanks to the superb angular
resolution of ACS, these observations will allow us to spectacularly
resolve the pulsar from its nebular background, providing the first
firm measure of the pulsar polarization which will be crucial to
assess, on a broader sample, the validity of the TPC model with
respect to other pulsars magnetosphere models. These observations will
also provide the first detailed polarization map of the nebula,
including the jet and the torus seen in our previous WFPC2 images.

WFPC2 10919

Eclipsing Binaries in the Local Group: II - Calibration of the
Zeropoint of the Cosmic Distance Scale and Fundamental Properties of
Stars in M33

(uses NIC3)

The Great Spiral Galaxy in Triangulum {M33} is potentially a crucial
calibrator for the Cosmic Distance Scale, and thus for determining the
age and evolution of the Universe. M33 is viewed face-on, has a simple
geometry, large and diverse stellar populations, and morphologies
similar to our Galaxy and other more distant galaxies used for
distance determinations. Yet currently the M33 distance {d ~ 830 +/-
110 kpc} still has measurement dispersions of 10-15%. We have
demonstrated, in our work on the LMC and M31 distances, that
double-line eclipsing binaries can serve as excellent "standard
candles." Distances derived from eclipsing binaries are basically
geometric and essentially free from many assumptions and uncertainties
that plague other less direct methods, such as metallicity differences
and calibration zeropoints. The absolute radii of the component stars
of eclipsing binaries can be determined to better than a few percent
from the time- tested analyses of their light and radial velocity
curves. With accurate determinations of radii, temperatures, and ISM
absorption it is possible to determine reliable distances. We are
extending our program of using eclipsing binaries as standard candles
to determine an accurate distance to M33. As a first step, we are
proposing to carry out HST/ACS spectrophotometry of a well suited
~19th mag ~O7 + ~O7 eclipsing binary system in M33 that has been
previously observed from the ground. HST/ACS prism/grism
low-resolution spectrophotometry {118-850 nm} is the only missing key
element of this program and is used to determine more reliable values
for T_eff, [Fe/H], and ISM extinction. These quantities, when combined
with the results from existing light and radial velocity curves for
the target, yield the stellar masses, radii, luminosities and,
importantly, the distance. The proposed HST/ACS program can be carried
out effectively with only 1 HST orbit. Based on our previous
experience, we expect to reduce the uncertainty of the M33 distance to
better than 5-7%, thereby leading to a firmer calibration of the
Cosmic Distance Scale and the zeropoint of the Hubble Constant {Ho}.

WFPC2 11028

WFPC2 Cycle 15 UV Earth Flats

Monitor flat field stability. This proposal obtains sequences of earth
streak flats to improve the quality of pipeline flat fields for the
WFPC2 UV filter set. These Earth flats will complement the UV earth
flat data obtained during cycles 8-14.

WFPC2 11070

WFPC2 CYCLE 15 Standard Darks - part II

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 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey
of a sample of 125 very X-ray luminous clusters in the redshift range
0.3-0.7. As demonstrated by the 25 snapshots obtained so far in
Cycle14 and Cycle15 these systems frequently exhibit strong
gravitational lensing as well as spectacular examples of violent
galaxy interactions. The proposed observations will provide important
constraints on the cluster mass distributions, the physical nature of
galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set
of optically bright, lensed galaxies for further 8-10m spectroscopy.
All of our primary science goals require only the detection and
characterization of high-surface-brightness features and are thus
achievable even at the reduced sensitivity of WFPC2. Because of their
high redshift and thus compact angular scale our target clusters are
less adversely affected by the smaller field of view of WFPC2 than
more nearby systems. Acknowledging the broad community interest in
this sample we waive our data rights for these observations. Due to a
clerical error at STScI our approved Cycle15 SNAP program was barred
from execution for 3 months and only 6 observations have been
performed to date - reinstating this SNAP at Cycle16 priority is of
paramount importance to reach meaningful statistics.

WFPC2 11169

Collisions in the Kuiper belt

For most of the 15 year history of observations of Kuiper belt
objects, it has been speculated that impacts must have played a major
role in shaping the physical and chemical characteristics of these
objects, yet little direct evidence of the effects of such impacts has
been seen. The past 18 months, however, have seen an explosion of
major new discoveries giving some of the first insights into the
influence of this critical process. From a diversity of observations
we have been led to the hypotheses that: {1} satellite- forming
impacts must have been common in the Kuiper belt; {2} such impacts led
to significant chemical modification; and {3} the outcomes of these
impacts are sufficiently predictable that we can now find and study
these impact-derived systems by the chemical and physical attributes
of both the satellites and the primaries. If our picture is correct,
we now have in hand for the first time a set of incredibly powerful
tools to study the frequency and outcome of collisions in the outer
solar system. Here we propose three linked projects that would answer
questions critical to the multiple prongs of our hypothesis. In these
projects we will study the chemical effects of collisions through
spectrophotometric observations of collisionally formed satellites and
through the search for additional satellites around primaries with
potential impact signatures, and we will study the physical effects of
impacts through the examination of tidal evolution in proposed impact
systems. The intensive HST program that we propose here will allow us
to fully test our new hypotheses and will provide the ability to
obtain the first extensive insights into outer solar system impact
processes.

WFPC2 11202

The Structure of Early-type Galaxies: 0.1-100 Effective Radii

The structure, formation and evolution of early-type galaxies is still
largely an open problem in cosmology: how does the Universe evolve
from large linear scales dominated by dark matter to the highly
non-linear scales of galaxies, where baryons and dark matter both play
important, interacting, roles? To understand the complex physical
processes involved in their formation scenario, and why they have the
tight scaling relations that we observe today {e.g. the Fundamental
Plane}, it is critically important not only to understand their
stellar structure, but also their dark-matter distribution from the
smallest to the largest scales. Over the last three years the SLACS
collaboration has developed a toolbox to tackle these issues in a
unique and encompassing way by combining new non-parametric strong
lensing techniques, stellar dynamics, and most recently weak
gravitational lensing, with high-quality Hubble Space Telescope
imaging and VLT/Keck spectroscopic data of early-type lens systems.
This allows us to break degeneracies that are inherent to each of
these techniques separately and probe the mass structure of early-type
galaxies from 0.1 to 100 effective radii. The large dynamic range to
which lensing is sensitive allows us both to probe the clumpy
substructure of these galaxies, as well as their low-density outer
haloes. These methods have convincingly been demonstrated, by our
team, using smaller pilot-samples of SLACS lens systems with HST data.
In this proposal, we request observing time with WFPC2 and NICMOS to
observe 53 strong lens systems from SLACS, to obtain complete
multi-color imaging for each system. This would bring the total number
of SLACS lens systems to 87 with completed HST imaging and effectively
doubles the known number of galaxy-scale strong lenses. The deep HST
images enable us to fully exploit our new techniques, beat down
low-number statistics, and probe the structure and evolution of
early-type galaxies, not only with a uniform data-set an order of
magnitude larger than what is available now, but also with a fully
coherent and self-consistent methodological approach!

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**************** 10**************** 10
FGS REacq**************** 03**************** 03
OBAD with Maneuver** ** * 26**************** 26

SIGNIFICANT EVENTS: (None)