Daily Rpt #4399

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*** # 4399

PERIOD COVERED: UT July 06, 07, 08, 2007 (DOY 187,188,189)

OBSERVATIONS SCHEDULED

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.

FGS 11294

The orbit of the most massive known astrometric binary

We have recently used FGS and HRC observations to {a} resolve HD
93129A into two components with very similar optical/UV colors and a
magnitude difference of 1.3 and to {b} detect their relative orbital
motion over a span of 8 years. HD 93129Aa is the prototype O2 If*
star, with an evolutionary mass near 100 M_Sun, while Ab is likely to
be a very early O main-sequence star with a similar or only slightly
smaller mass. Our HST astrometric measurements yield a total mass
above 100 M_Sun, thus confirming the extremely high mass of the
binary, and indicate that the system appears to be approaching
periastron. We request new FGS observations to {a} calculate the mass
ratio of the system by measuring the orbit of each of the components
with respect to the nearby stars, {b} obtain the periastron epoch, and
{c} start measuring the orbit in order to produce an estimate of the
total mass. These measurements are crucial to shed light on the value
of the stellar upper mass limit.

WFPC2 11289

SL2S: The Strong Lensing Legacy Survey

Recent systematic surveys of strong galaxy-galaxy lenses {CLASS,
SLACS, GOODS, etc.} are producing spectacular results for galaxy
masses roughly below a transition mass M~10^13 Mo. The observed lens
properties and their evolution up to z~0.2, consistent with numerical
simulations, can be described by isothermal elliptical potentials. In
contrast, modeling of giant arcs in X-ray luminous clusters {halo
masses M ~10^13 Mo} favors NFW mass profiles, suggesting that dark
matter halos are not significantly affected by baryon cooling. Until
recently, lensing surveys were neither deep nor extended enough to
probe the intermediate mass density regime, which is fundamental for
understanding the assembly of structures. The CFHT Legacy Survey now
covers 125 square degrees, and thus offers a large reservoir of strong
lenses probing a large range of mass densities up to z~1. We have
extracted a list of 150 strong lenses using the most recent CFHTLS
data release via automated procedures. Following our first SNAPSHOT
proposal in cycle 15, we propose to continue the Hubble follow-up
targeting a larger list of 130 lensing candidates. These are
intermediate mass range candidates {between galaxies and clusters}
that are selected in the redshift range of 0.2-1 with no a priori
X-ray selection. The HST resolution is necessary for confirming the
lensing candidates, accurate modeling of the lenses, and probing the
total mass concentration in galaxy groups up to z~1 with the largest
unbiased sample available to date.

WFPC2 11229

SEEDS: The Search for Evolution of Emission from Dust in Supernovae
with HST and

The role that massive stars play in the dust content of the Universe
is extremely uncertain. It has long been hypothesized that dust can
condense within the ejecta of supernovae {SNe}, however there is a
frustrating discrepancy between the amounts of dust found in the early
Universe, or predicted by nucleation theory, and inferred from SN
observations. Our SEEDS collaboration has been carefully revisiting
the observational case for dust formation by core-collapse SNe, in
order to quantify their role as dust contributors in the early
Universe. As dust condenses in expanding SN ejecta, it will increase
in optical depth, producing three simultaneously observable phenomena:
{1} increasing optical extinction; {2} infrared {IR} excesses; and {3}
asymmetric blue-shifted emission lines. Our SEEDS collaboration
recently reported all three phenomena occuring in SN2003gd,
demonstrating the success of our observing strategy, and permitting us
to derive a dust mass of up to 0.02 solar masses created in the SN. To
advance our understanding of the origin and evolution of the
interstellar dust in galaxies, we propose to use HST's WFPC2 and
NICMOS instruments plus Spitzer's photometric instruments to monitor
ten recent core- collapse SNe for dust formation and, as a bonus,
detect light echoes that can affect the dust mass estimates. These
space-borne observations will be supplemented by ground- based
spectroscopic monitoring of their optical emission line profiles.
These observations would continue our 2-year HST and Spitzer
monitoring of this phenomena in order to address two key questions: Do
all SNe produce dust? and How much dust do they produce? As all the SN
are witin 15 Mpc, each SN stands an excellent chance of detection with
HST and Spitzer and of resolving potential light echoes.

FGS 11211

An Astrometric Calibration of Population II Distance Indicators

In 2002 HST produced a highly precise parallax for RR Lyrae. That
measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a
useful result, judged by the over ten refereed citations each year
since. It is, however, unsatisfactory to have the direct,
parallax-based, distance scale of Population II variables based on a
single star. We propose, therefore, to obtain the parallaxes of four
additional RR Lyrae stars and two Population II Cepheids, or W Vir
stars. The Population II Cepheids lie with the RR Lyrae stars on a
common K-band Period-Luminosity relation. Using these parallaxes to
inform that relationship, we anticipate a zero-point error of 0.04
magnitude. This result should greatly strengthen confidence in the
Population II distance scale and increase our understanding of RR
Lyrae star and Pop II Cepheid astrophysics.

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that
prediction. It is, however, a prediction of extrasolar planetary
system architecture as yet untested by direct observation for main
sequence stars other than the Sun. To provide such a test, we propose
to carry out FGS astrometric studies on four stars hosting seven
companions. Our understanding of the planet formation process will
grow as we match not only system architecture, but formed planet mass
and true distance from the primary with host star characteristics for
a wide variety of host stars and exoplanet masses. We propose that a
series of FGS astrometric observations with demonstrated 1 millisecond
of arc per- observation precision can establish the degree of
coplanarity and component true masses for four extrasolar systems: HD
202206 {brown dwarf+planet}; HD 128311 {planet+planet}, HD 160691 = mu
Arae {planet+planet}, and HD 222404AB = gamma Cephei {planet+star}. In
each case the companion is identified as such by assuming that the
minimum mass is the actual mass. For the last target, a known stellar
binary system, the companion orbit is stable only if coplanar with the
AB binary orbit.

WFPC2 11178

Probing Solar System History with Orbits, Masses, and Colors of
Transneptunian Binaries

The recent discovery of numerous transneptunian binaries {TNBs} opens
a window into dynamical conditions in the protoplanetary disk where
they formed as well as the history of subsequent events which sculpted
the outer Solar System and emplaced them onto their present day
heliocentric orbits. To date, at least 47 TNBs have been discovered,
but only about a dozen have had their mutual orbits and separate
colors determined, frustrating their use to investigate numerous
important scientific questions. The current shortage of data
especially cripples scientific investigations requiring statistical
comparisons among the ensemble characteristics. We propose to obtain
sufficient astrometry and photometry of 23 TNBs to compute their
mutual orbits and system masses and to determine separate primary and
secondary colors, roughly tripling the sample for which this
information is known, as well as extending it to include systems of
two near-equal size bodies. To make the most efficient possible use of
HST, we will use a Monte Carlo technique to optimally schedule our
observations.

WFPC2 11175

UV Imaging to Determine the Location of Residual Star Formation in
Galaxies Recently Arrived on the Red Sequence

We have indentified a sample of low-redshift {z = 0.04 - 0.10}
galaxies that are candidates for recent arrival on the red sequence.
They have red optical colors indicative of old stellar populations,
but blue UV-optical colors that could indicate the presence of a small
quantity of continuing or very recent star formation. However, their
spectra lack the emission lines that characterize star-forming
galaxies. We propose to use ACS/SBC to obtain high- resolution imaging
of the UV flux in these galaxies, in order to determine the spatial
distribution of the last episode of star formation. WFPC2 imaging will
provide B, V, and I photometry to measure the main stellar light
distribution of the galaxy for comparison with the UV imaging, as well
as to measure color gradients and the distribution of interstellar
dust. This detailed morphological information will allow us to
investigate the hypothesis that these galaxies have recently stopped
forming stars and to compare the observed distribution of the last
star formation with predictions for several different mechanisms that
may quench star formation in galaxies.

NIC2 11157

NICMOS Imaging Survey of Dusty Debris Around Nearby Stars Across the
Stellar Mass Spectrum

Association of planetary systems with dusty debris disks is now quite
secure, and advances in our understanding of planet formation and
evolution can be achieved by the identification and characterization
of an ensemble of debris disks orbiting a range of central stars with
different masses and ages. Imaging debris disks in starlight scattered
by dust grains remains technically challenging so that only about a
dozen systems have thus far been imaged. A further advance in this
field needs an increased number of imaged debris disks. However, the
technical challege of such observations, even with the superb
combination of HST and NICMOS, requires the best targets. Recent HST
imaging investigations of debris disks were sample-limited not limited
by the technology used. We performed a search for debris disks from a
IRAS/Hipparcos cross correlation which involved an exhaustive
background contamination check to weed out false excess stars. Out of
~140 identified debris disks, we selected 22 best targets in terms of
dust optical depth and disk angular size. Our target sample represents
the best currently available target set in terms of both disk
brightness and resolvability. For example, our targets have higher
dust optical depth, in general, than newly identified Spitzer disks.
Also, our targets cover a wider range of central star ages and masses
than previous debris disk surveys. This will help us to investigate
planetary system formation and evolution across the stellar mass
spectrum. The technical feasibility of this program in two-gyro mode
guiding has been proven with on- orbit calibration and science
observations during HST cycles 13, 14, and 15.

WFPC2 11113

Binaries in the Kuiper Belt: Probes of Solar System Formation and
Evolution

The discovery of binaries in the Kuiper Belt and related small body
populations is powering a revolutionary step forward in the study of
this remote region. Three quarters of the known binaries in the Kuiper
Belt have been discovered with HST, most by our snapshot surveys. The
statistics derived from this work are beginning to yield surprising
and unexpected results. We have found a strong concentration of
binaries among low-inclination Classicals, a possible size cutoff to
binaries among the Centaurs, an apparent preference for nearly equal
mass binaries, and a strong increase in the number of binaries at
small separations. We propose to continue this successful program in
Cycle 16; we expect to discover at least 13 new binary systems,
targeted to subgroups where these discoveries can have the greatest
impact.

NIC2 11101

The Relevance of Mergers for Fueling AGNs: Answers from QSO Host
Galaxies

The majority of QSOs are known to reside in centers of galaxies that
look like ellipticals. Numerical simulations have shown that remnants
of galaxy mergers often closely resemble elliptical galaxies. However,
it is still strongly debated whether the majority of QSO host galaxies
are indeed the result of relatively recent mergers or whether they are
completely analogous to inactive ellipticals to which nothing
interesting has happened recently. To address this question, we
recently obtained deep HST ACS images for five QSO host galaxies that
were classified morphologically as ellipticals {GO-10421}. This pilot
study revealed striking signs of tidal interactions such as ripples,
tidal tails, and warped disks that were not detected in previous
studies. Our observations show that at least some "elliptical" QSO
host galaxies are the products of relatively recent merger events
rather than old galaxies formed at high redshift. However, the
question remains whether the host galaxies of classical QSOs are truly
distinct from inactive ellipticals and whether there is a connection
between the merger events we detect and the current nuclear activity.
We must therefore place our results into a larger statistical context.
We are currently conducting an HST archival study of inactive
elliptical galaxies {AR-10941} to form a control sample. We now
propose to obtain deep HST/WFPC2 images of 13 QSOs whose host galaxies
are classified as normal ellipticals. Comparing the results for both
samples will help us determine whether classical QSOs reside in normal
elliptical galaxies or not. Our recent pilot study of five QSOs
indicates that we can expect exciting results and deep insights into
the host galaxy morphology also for this larger sample of QSOs. A
statistically meaningful sample will help us determine the true
fraction of QSO hosts that suffered strong tidal interactions and
thus, whether a merger is indeed a requirement to trigger nuclear
activity in the most luminous AGNs. In addition to our primary science
observations with WFPC2, we will obtain NICMOS3 parallel observations
with the overall goal to select and characterize galaxy populations at
high redshifts. The imaging will be among the deepest NICMOS images:
These NICMOS images are expected to go to a limit a little over 1
magnitude brighter than HUDF-NICMOS data, but over 13 widely separated
fields, with a total area about 1.5 times larger than HUDF-NICMOS.
This separation means that the survey will tend to average out effects
of cosmic varience. The NICMOS3 images will have sufficient resolution
for an initial characterization of galaxy morphologies, which is
currently one of the most active and promising areas in approaching
the problem of the formation of the first massive galaxies. The depth
and area coverage of our proposed NICMOS observations will also allow
a careful study of the mass function of galaxies at these redshifts.
This provides a large and unbiased sample, selected in terms of
stellar mass and unaffected by cosmic variance, to study the on-going
star formation activity as a function of mass {i.e. integrated star
formation} at this very important epoch.

NIC1 11063

NICMOS Focus Monitoring

This program is a version of the standard focus sweep used since cycle
7. It has been modified to go deeper and uses more narrow filters for
improved focus determination. For Cycle14 a new source has been added
in order to accomodate 2-gyro mode: the open cluster NGC1850. The old
target, the open cluster NGC3603, will be used whenever available and
the new target used to fill the periods when NGC3603 is not visible.
Steps: a} Use refined target field positions as determined from cycle
7 calibrations b} Use MULTIACCUM sequences of sufficient dynamic range
to account for defocus c} Do a 17- point focus sweep, +/- 8mm about
the PAM mechanical zeropoint for each cameras 1 and 2, in 1.0mm steps.
d} Use PAM X/Y tilt and OTA offset slew compensations refined from
previous focus monitoring/optical alignment activities

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/ACS/HRC/WFPC 11020

Cycle 15 Focus Monitor

The focus of HST is measured primarily with ACS/HRC over full CVZ
orbits to obtain accurate mean focus values via a well sampled
breathing curve. Coma and astigmatism are also determined from the
same data in order to further understand orbital effects on image
quality and optical alignments. To monitor the stability of ACS to
WFPC2 relative focii, we've carried over from previous focus monitor
programs parallel observations taken with the two cameras at suitable
orientations of previously observed targets, and interspersed them
with the HRC CVZ visits.

FGS 11019

Monitoring FGS1r's Interferometric Response as a Function of Spectral
Color

This proosal uses FGS1r in Transfer mode to observe standard single
stars of a variety of spectral types to obtain point source
interferograms for the Transfer mode calibration library. In specific
cases, the calibration star will also be observed in POS mode multiple
times with the F583W and F5ND elements to provide the data to verify
the stabiligy of the cross filter calibration.

WFPC2 10837

Establishing the Nature of a Mysterious Evolved Star, HD179821

We propose to reobserve the spherical circumstellar shells of an
evolved star, HD 179821. The nature of this object, whether it is an
intermediate-mass post-asymptotic giant branch star or a massive
super-giant, has been debated over years. The past investigations
scrutinized the properties of the object and its circumstellar shells.
This enigmatic object possesses characteristics of a post-AGB star and
a yellow hyper-giant, and there is no evidence that unambiguously
defines the nature of this object. The circumstellar shell of HD
179821 was imaged in the previous WFPC2 observations during cycle 6,
and its multiple concentric arcs extending out to about 8 arcsec were
revealed. The purpose of the proposed HST observations is to obtain
the second-epoch images of this source and perform proper-motion
measurements of the shells in order to directly determine the distance
to this object, thereby establishing its incredibly elusive nature
once and for all. It has been nearly 10 years since the last
observations. Given the object's rather high expansion velocity of 34
km/s, the expected angular expansion is 72 milli-arcsec if the object
is located at 1 kpc and 12 milli-arcsec if 6 kpc. These values are
well above the smallest material motion we can measure, 2 to 3
milli-arcsec, in our methodology that has been proven in our recent
proper-motion measurements on a proto-planetary nebula, the Egg
Nebula, using the archived HST/NICMOS near-IR continuum data. We
estimate that the new distance measurement is of about 10% error. Once
we obtain the distance to HD 179821, we will construct a radiative
transfer model of the object to constrain physical parameters of the
star and shells with a greater certainty. Then, we can confront
theories of the stellar evolution with the newly obtained revelation.
In addition, we can examine if all shells are moving at the same
speed, since there are multiple shells around HD 179821. It is
typically assumed that the expansion of the circumstellar shells is
constant over the lifetime of the nebula. Our results will immediately
test the validity of this one of the most fundamental assumptions in
the stellar outflows.

ACS/WFC 10787

Modes of Star Formation and Nuclear Activity in an Early Universe
Laboratory

Nearby compact galaxy groups are uniquely suited to exploring the
mechanisms of star formation amid repeated and ongoing gravitational
encounters, conditions similar to those of the high redshift universe.
These dense groups host a variety of modes of star formation, and they
enable fresh insights into the role of gas in galaxy evolution. With
Spitzer mid-IR observations in hand, we have begun to obtain high
quality, multi-wavelength data for a well- defined sample of 12 nearby
{4500km/s} compact groups covering the full range of evolutionary
stages. Here we propose to obtain sensitive BVI images with the
ACS/WFC, deep enough to reach the turnover of the globular cluster
luminosity function, and WFPC2 U-band and ACS H-alpha images of
Spitzer-identified regions hosting the most recent star formation. In
total, we expect to detect over 1000 young star clusters forming
inside and outside galaxies, more than 4000 old globular clusters in
40 giant galaxies {including 16 early-type galaxies}, over 20 tidal
features, approximately 15 AGNs, and intragroup gas in most of the 12
groups. Combining the proposed ACS images with Chandra observations,
UV GALEX observations, ground-based H-alpha imaging, and HI data, we
will conduct a detailed study of stellar nurseries, dust, gas
kinematics, and AGN.

ACS/WFC 10760

Black Hole X-ray Novae in M31

We have been carring out a Chandra {GO+GTO} and HST {GO} program to
find Black Hole X-ray Nova {BHXN} and their optical counterparts in
M31 for several years. To date we have found 2 dozen BHXN and 3 HST
optical counterparts for these BHXN. Our results suggest a rather high
ratio of BH to neutron star {NS} binaries, or a high duty cycle for
the BHXN. We propose to continue this program, with the goal of
determining the orbital period distribution and duty cycles of these
BHXN. Current results yield 3 orbital periods and 2 upper limits. Our
proposed observations will ~double the total number of periods and
therefore yield sufficient numbers to make a first approximation of
the orbital period distribution. The orbital period distribution is
the fundamental observable parameter any binary stellar evolution
models must match, and the duty cycle is very poorly known but
directly influences the binary lifetime. M31 is the only galaxy in
which this extra-galactic study of BHXN is feasible.

ACS/WFC 10583

Resolving the LMC Microlensing Puzzle: Where Are the Lensing Objects
?

We are requesting 32 HST orbits to help ascertain the nature of the
population that gives rise to the observed set of microlensing events
towards the LMC. The SuperMACHO project is an ongoing ground-based
survey on the CTIO 4m that has demonstrated the ability to detect LMC
microlensing events in real-time via frame subtraction. The
improvement in angular resolution and photometric accuracy available
from HST will allow us to 1} confirm that the detected flux excursions
arise from LMC source stars rather than extended objects {such as for
background supernovae or AGN}, and 2} obtain reliable baseline flux
measurements for the objects in their unlensed state. The latter
measurement is important to resolve degeneracies between the event
timescale and baseline flux, which will yield a tighter constraint on
the microlensing optical depth.

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:

#17659-0* ESTR Reconditioning (Generic) @ 187/1318z
#18042-1* MA/GN Recorder Dump Test (Generic) @ 187/1630z

COMPLETED OPS NOTES: (None)

******************************* SCHEDULED***** SUCCESSFUL
FGS GSacq*********************** 22************* 22
FGS REacq*********************** 20************* 20
OBAD with Maneuver********* **** 81************* 81

SIGNIFICANT EVENTS: (None)