Daily #4015

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4015

PERIOD COVERED: UT December 23,24,25,26, 2005 (DOY 357,358,359,360)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration - CR Persistence Part 3

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 10778

WFPC2 WF4 Supplemental Darks

A anomaly has been found in images from the WF4 CCD in WFPC2. The WF4
CCD bias level appears to have become unstable, resulting in sporadic
images with either low or zero bias level. The severity and frequency
of the problem is rapidly increasing, and it is possible that WF4 will
soon become unusable if no work-around is found. The other three CCDs
{PC1, WF2, and WF3} appear to be unaffected and continue to operate
properly. These darks are to supplement those in program 10748 to
ensure sufficient dark frames for routine calibration. As the WF4
anomaly grows worse, we are beginning to see episodes where too many
darks are corrupted and are unusable.

WFPC2 10772

WF4 Anomaly Characterization

A anomaly has been found in images from the WF4 CCD in WFPC2. The WF4
CCD bias level appears to have become unstable, resulting in sporadic
images with either low or zero bias level. The other three CCDs {PC1,
WF2, and WF3} appear to be unaffected and continue to operate
properly. The impacts from "low" and "zero" bias are somewhat
different, but in both cases the effects are immediately obvious. At
present there are still many images which appear fine and unaffected,
but the situation is quickly evolving. We believe the science impact
for most observers will be minimal. Targets are by default placed on
either PC1 or WF3 which continue to operate properly. However,
observers requiring the full field of view {survey projects, large
targets, etc.} will potentially lose one-third of their imaging area.
Our understanding of this anomaly is still evolving, and most of the
information is tentative.

WFPC2 10751

WFPC2 CYCLE 14 Intflat Linearity Check and Filter Rotation Anomaly
Monitor

Intflat observations will be taken to provide a linearity check: the
linearity test consists of a series of intflats in F555W, in each gain
and each shutter. A combination of intflats, visflats, and earthflats
will be used to check the repeatability of filter wheel motions.
{Intflat sequences tied to decons, visits 1-18 in prop 10363, have
been moved to the cycle 14 decon proposal 10744 for easier
scheduling.} Note: long-exposure WFPC2 intflats must be scheduled
during ACS anneals to prevent stray light from the WFPC2 lamps from
contaminating long ACS external exposures.

WFPC2 10748

WFPC2 CYCLE 14 Standard Darks

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.

ACS/HRC/WFC 10729

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS. Changes from cycle 13:- The default
gain for WFC is 2 e-/DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period Oct, 2 2005- May, 29-2006. The
second half of the program has a different proposal number: 10758.

ACS/HRC 10617

HST / Chandra Monitoring of a Dramatic Flare in the M87 Jet

As the nearest galaxy with an optical jet, M87 affords an unparalleled
opportunity to study extragalactic jet phenomena at the highest
resolution. During 2002, HST and Chandra monitoring of the M87 jet
detected a dramatic flare in knot HST-1 located ~1" from the nucleus.
As of late 2004 its brightness has increased fifty-fold in the optical
band, and continues to increase sharply; the X-rays show a similarly
dramatic outburst. In both bands HST-1 now greatly exceeds the nucleus
in brightness. To our knowledge this is the first incidence of an
optical or X-ray outburst from a jet region which is spatially
distinct from the core source -- this presents an unprecedented
opportunity to study the processes responsible for non-thermal
variability and the X-ray emission. We propose seven epochs of
Chandra/ACIS observation {5ksec each}. We also include a brief HRC/ACS
observations that will be used to gather spectral information and map
the magnetic field structure. The results of this investigation are of
key importance not only for understanding the nature of the X-ray
emission of the M87 jet, but also for understanding flares in blazar
jets, which are highly variable, but where we have never before been
able to resolve the flaring region in the optical or X-rays. These
observations will allow us to test synchrotron emission models for the
X-ray outburst, constrain particle acceleration and loss timescales,
and study the jet dynamics associated with this flaring component.

FGS 10614

Internal Structure and Figures of Binary Asteroids

The goal of this proposal is to obtain very important information on
the internal structure of a number of asteroids, and insight on the
gravitational reaccumulation-process after a catastrophic disruptive
collision. High resolutions observations with the HST/FGS
interferometer are proposed to obtain high precision data for the
topographic shape and size of a number of selected asteroids. Here we
focus on objects with satellites, hence with known masses, so that the
bulk density and porosity will be derived in the most accurate manner.
This will yield plausible estimates on the internal properties of the
objects, test wether they are close or not to figures of equilibrium
{in terms of shape and adimensional rotational frequency}, and provide
estimates of their relative density. The HST/FGS in interferometric
mode is an ideal facility to carry out this program.

WFPC2 10608

Probing the star formation law in the extreme outer limits of M83, a
prototypical XUV-disk galaxy

The Galaxy Evolution Explorer {GALEX} has discovered a new sub-class
of spiral galaxy, which we refer to as extended UV-disk {XUV-disk}
galaxies. They are distinguished by conspicuous UV-bright star
clusters located at galactocentric radii extending to many times the
optical {R25} extent, and appear to represent a population of spiral
galaxies still actively building, or augmenting, their stellar disk.
However, XUV-disks pose a mystery in the form of a relative lack of
HII regions {traced by H-alpha emission} associated with outer disk,
UV-bright stellar clusters. M83 is an XUV-disk prototype and the focus
of this proposal. It has an H-alpha surface brightness profile
characterized by a steep decline at the radius beyond which the
gaseous disk is thought to become dynamically stable {against collapse
and ensuing star formation}, but GALEX UV profiles show no "edge" at
this location. Our HST study of M83 aims to resolve this puzzling
discrepancy, confirmed in several XUV-disks, by searching for
Lyman-continuum producing O stars that are either absent or present
without nebulosity. HST provides the only means of resolving
individual massive stars in the FUV band at M83's distance. Without
HST, we lose the critical ability to photometrically classify O and B
stars. Our multiwavelength observations will also constrain the
history of star formation in the outer disk over Gyr timescales by
characterizing the evolved stellar population, both using resolved
giants and color analysis of the diffuse background.

ACS/WFC 10596

AGNs with Intermediate-mass Black Holes: A Test of the Black
Hole-Bulge Paradigm

The recent progress in the study of central black holes in galactic
nuclei has led to a general consensus that supermassive {10^6-10^9
solar mass} black holes are closely connected with the formation and
evolutionary history of large galaxies, especially their bulge
component. Two outstanding issues, however, remain unresolved. Can
central black holes form in the absence of a bulge? And does the mass
function of central black holes extend below 10^6 solar masses?
Intermediate-mass black holes {10^4-10^6 solar masses}, if they exist,
may offer important clues to the nature of the seeds of supermassive
black holes. In a first systematic search using the Sloan Digital Sky
Survey, we have recently discovered 19 Type 1 AGNs with candidate
intermediate-mass black holes that reside in low-luminosity,
presumably late-type host galaxies. Follow-up observations with Keck
indicate that these objects obey the low-mass extension of the
well-known correlation between black hole mass and bulge stellar
velocity dispersion. However, very little is known about the host
galaxies themselves, including the crucial question of whether they
have bulges or not. We propose to obtain ACS/WFC images of this unique
sample of AGNs in order to investigate the detailed structural
properties of the host galaxies. We are particularly keen to determine
whether the hosts contain bulges, and if so, where they lie on the
fundamental plane of spheroids compared to the bulges of supermassive
black holes. We will also be able to measure an accurate optical
luminosity for the AGN, which is an essential ingredient to improve
the current mass estimates.

ACS/WFC 10592

An ACS Survey of a Complete Sample of Luminous Infrared Galaxies in
the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
`luminous infrared galaxies' {LIRGs} are primarily interacting or
merging disk galaxies undergoing enhanced star formation and Active
Galactic Nuclei {AGN} activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
ACS/WFC imaging of a complete sample of 88 L_IR 10^11.4 L_sun
luminous infrared galaxies in the IRAS Revised Bright Galaxy Sample
{RBGS: i.e., 60 micron flux density 5.24 Jy}. This sample is ideal
not only in its completeness and sample size, but also in the
proximity and brightness of the galaxies. The superb sensitivity,
resolution, and field of view of ACS/WFC on HST enables a unique
opportunity to study the detailed structure of galaxies that sample
all stages of the merger process. Imaging will be done with the F439W
and F814W filters {B and I-band} to examine as a function of both
luminosity and merger state {i} the evidence at optical wavelengths of
star formation and AGN activity and the manner in which instabilities
{bars and bridges} in the galaxies may funnel material to these active
regions, {ii} the relationship between star formation and AGN
activity, and {iii} the structural properties {AGN, bulge, and disk
components} and fundamental parameters {effective radius and surface
brightness} of LIRGs and their similarity with putative evolutionary
byproducts {elliptical, S0 and classical AGN host galaxies}. This HST
survey will also bridge the wavelength gap between a Spitzer imaging
survey {covering seven bands in the 3.6-160 micron range} and a GALEX
UV imaging survey of these galaxies, but will resolve complexes of
star clusters and multiple nuclei at resolutions well beyond the
capabilities of either Spitzer or GALEX. The combined datasets will
result in the most comprehensive multiwavelength study of interacting
and merging galaxies to date.

WFPC2/ACS/WFC 10590

Star-Formation History of an Unmerged Fragment: the Leo A Dwarf Galaxy

The Leo A dwarf irregular is the only known Local Group galaxy that on
the weight of current evidence has been suggested to have experienced
its first star formation within the past 2-3 billion years. As a
galaxy that could have been almost purely gaseous during the epoch of
giant galaxy assembly, Leo A is the best nearby candidate to be a
redshift zero analogue to the major building blocks of the Milky Way.
We propose to obtain deep optical images of Leo A with the ACS/WFC to
achieve three main goals: 1} To establish the fractions of
star-formation, by mass, that occurred prior and subsequent to the
main epoch of hierarchical merging {redshift z ~ 2-4, Age ~ 10-12.5
Gigayears}; 2} to measure the time variation in Leo A's star-formation
rate over the past 10 Gyr, based on statistical analyses of its {V-I,
I} color-magnitude diagram; and 3} to measure the radial distributions
of young and old stellar populations and quantify the degree to which
the optically prominent, young population is embedded in an extended,
low-surface brightness sheet or halo of ancient stars. Because of the
distance modulus {24.5 mag} and high degree of stellar crowding at the
level of the oldest main-sequence turnoffs, the observations necessary
to achieve these goals are unobtainable except with HST. The ONLY way
to reliably derive the star-formation history of Leo A over its entire
lifetime is with photometry to magnitudes of {B, I} = {28.6, 27.9},
the level of the oldest main-sequence turnoff in Leo A. These data
would confirm and extend the limited inferences obtained from WFPC2
photometry over 2 magnitudes less deep, and provide the first
opportunity to measure the complete star-formation history of a
potential "living fossil" analogue to the building blocks of the Milky
Way. We propose to use WFPC2 in parallel to measure radial variations
in the stellar populations between the galaxy's core and outskirts.
Because the expected 2-gyro jitter ellipse is comparable to the pixel
scale of ACS/WFC, we rely on point-spread function fitting photometry,
and we require no special scheduling constraints, our proposed program
would be virtually unaffected by entry into 2-gyro mode.

ACS/WFC 10586

The Rosetta Stone without a Distance: Hunting for Cepheids in the
Primordial Galaxy I Zw 18

The Blue Compact Dwarf galaxy I Zw 18 is one of the most intriguing
objects in the Local Universe. It has the lowest nebular metallicity
of all known galaxies {Z=1/32 solar}. It has long been regarded as a
possible example of a galaxy undergoing its first burst of star
formation. However, its real evolutionary state continues to be
controversial. The WFPC2 and NICMOS detection of AGB stars by our
group and others suggested the presence of an underlying older
population. However, deeper ACS observations by Izotov & Thuan {2004}
recently failed to detect the signature of RGB stars. This was
interpreted as confirmation that I Zw 18 is in fact a galaxy "in
formation", a local analog of primordial galaxies in the distant
Universe. This result was widely reported in the international news
media. However, an alternative possibility is that I Zw 18 is somewhat
further away than previously believed, so that Red Giant Branch stars
were too faint to detect. Quoted distances in the literature have
ranged from 10 to 20 Mpc. We intend to resolve this controversy by
direct determination of the distance to 1 Mpc accuracy using Cepheids.
For this we request 12 visits of two orbits each, to execute at
carefully planned intervals. We will obtain V and I band ACS/WFC
photometry in each visit. The new data will be combined with archival
data, but we show that the archival data by themselves are
insufficient to achieve our science goals. The distance will allow us
to place I Zw 18 into its proper place in the evolutionary sequence of
galaxy formation.

ACS/WFC 10582

Probing The Galaxy-wide Globular Cluster - Low Mass X-ray Binary
Connection in Early-type Galaxies

The combination of high-resolution imaging from Hubble {HST} and
Chandra {CXO} has completely revolutionized our understanding of
extragalactic low-mass X-ray binaries {LMXBs} and globular clusters
{GCs}; however, studies have been limited by short X-ray exposures and
relatively small fields. NGC 4697 amd NGC 4365 are relatively simple
elliptical galaxies in the X- ray that will have deep CXO
observations. We propose ACS observations in six flanking fields per
galaxy to provide a study of the GC-LMXB connection in normal
early-type galaxies with unprecedented depth, spatial resolution and
areal coverage. Combined with existing central field observations, we
will detect ~900 and ~2700 GCs GCs in most of NGC 4697 and all of NGC
4365. These two galaxies will have the greatest number of detected
GC-LMXBs to date {~70 & 120}. We will measure the fraction of LMXBs
found in GCs, and the fraction of GCs which contain LMXBs, as a
function of X-ray luminosity, galactocentric distance, color, GC
half-light radius, and local GC specific frequency. We will test
existing models of GC formation/evolution and LMXB
formation/evolution. Using the radial profile of optical light, GCs,
and LMXBS, we will determine the percentage of field LMXBs which may
have originated in GCs.

ACS/WFC 10576

An ACS Imaging Survey of the Galaxies Hosting Strong Mg II Absorption

Strong MgII absorbers {with rest-frame absorption equivalent width
W_MgII 0.3 A} at redshift z 1 are known to arise in extended
gaseous halos around luminous galaxies. Detailed absorption line
studies based on high-solution spectra of background quasars yield
tight constraints on the metallicity, ionization state, and kinematics
of the gaseous clouds. But whether they originate in gas accreted from
surrounding satellite galaxies or outflows associated with active
starburst in the host galaxies remains unclear. We have recently
completed a search of the Sloan Digital Sky Survey data archive for
strong MgII absorbers and identified over 1000 new systems that are
previously unknown. A subset of these MgII absorbers with W_MgII 1.8
A exhibit extreme kinematics with velocity widths {exceeding 200 km/s}
in our follow-up echelle spectra. Their dynamics are consistent with
various scenarios that include gas accretion {with speeds exceeding
the virial velocity} and starburst outflows {possibly driven by recent
merger events}. Independent of their exact nature, it is clear that
strong MgII systems serve as signposts to galactic halos with extreme
gas dynamics. Here we propose to conduct a snapshot survey of galaxies
in the fields toward high-redshift quasars with known, strong MgII
absorbers at 0.5 z 2. We plan to obtain high spatial-resolution
ACS/WFC images of 60 fields to uncover galaxies fainter than L* at the
redshifts of these absorbers and study their morphology. We will
complement the HST observations with follow-up spectroscopic
observations and IR images acquired at the Keck and Magellan
Observatories to for redshift identifications and for measuring
broad-band colors. We will investigate the correlation between
absorption line kinematics and galaxy morphology. In particular, we
will address whether on-going mergers is responsible for the extreme
dynamics observed in MgII absorption based on their rest-frame
ultraviolet morphology.

ACS/WFC 10574

Witnessing Galaxy Transformation in Galaxy Groups at z 1

The recent discover of five galaxy groups in the Lynx supercluster
region offers us the exciting opportunity to observe for the first
time groups in the process of collapsing into a merging pair of
clusters at z 1. Our current picture of structure formation suggests
that substantial evolution of galaxy properties can occur in groups
and filaments well before they enter the environs of massive clusters.
However, neither current theoretical models nor observations give us a
complete understanding of the relative importance of the different
physical processes that control the structural and spectral
transformations that occur prior to, during, and after infall into a
dense environment. We propose direct observation of these newly
discovered dynamically young structures in the Lynx region, in order
to provide a critical benchmark in testing not only whether galaxy
evolution occurs mostly prior to entry into the densest regions but
will also constrain the relative importance of initial conditions in
determining the fate of galaxy systems. Our analysis of these proposed
ACS measurements will be complemented with an unique dataset we have
already in the optical, infrared, mid-infrared, and X-ray.

ACS/HRC 10564

Resolving Ultracool White Dwarf Binaries

We propose an ACS/HRC imaging survey of the coolest white dwarfs known
in order to search for binarity. Current models fail to match observed
spectral energy distributions of these sub- 4000K stellar remnants,
consistently predicting much lower luminosities than observed. A
possible explanation is that they are binary in nature. Because these
cool degenerates have no spectral features, the only way to
investigate their apparent overluminosity is with very high resolution
imaging, which can only be done with HST {these stars are far too
faint to be observed with adaptive optics on the ground}. Optical
wavelengths are ideal because the spectral energy distributions of
these old degenerates peak near 600 nm. With the F435W filter we will
be able to partially resolve equally luminous binaries as close as
0.02", which corresponds to within 0.6 AU for over half of the 12
proposed target stars. The collected data will be critical in
determining whether these stars represent the oldest white dwarfs in
the solar neighborhood.

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/HRC 10545

Icy planetoids of the outer solar system

Early HST studies of satellites of Kuiper belt object focussed on the
50-200 km objects that were the largest known at the time. In the past
3 years we have discovered a population of much more rare and much
larger {500-2000+ km} icy planetoids in the Kuiper belt. These objects
are the largest and brightest known in the Kuiper belt and, in the era
when we now know of more than 1000 Kuiper belt objects, these few
planetoids are likely to be the focus of much of the research on
physical properties of the outer solar system for years to come. We
are currently engaged in an intensive program involving Spitzer, Keck,
and other telescopes to study the physical and dynamical properties of
this new population. HST is uniquely capable of addressing one
parameter fundamental to completing the physical picture of these
planetoids: the existence and size of any satellites. The detection
and characterization of satellites to these large planetoids would
allow us to address unique issues critical to the formation and
evolution of the outer solar system, including the measurement of
densities, internal properties, sizes and shapes of these objects, the
study of binary formation as a function of primary size, and the
context of the Pluto-Charon binary. For these bright objects, a
satellite search takes less than a full orbit, allowing the
opportunity for a new project on UV spectroscopy of the planetoids to
piggyback at no added time cost. This poorly explored spectral range
has the potential to show unique signatures of trapped gasses,
cosmochemically important ices, and complex organic materials.

ACS/WFC 10543

Microlensing in M87 and the Virgo Cluster

Resolving the nature of dark matter is an urgent problem. The results
of the MACHO survey of the Milky Way dark halo toward the LMC indicate
that a significant fraction of the halo consists of stellar mass
objects. The VATT/Columbia survey of M31 finds a similar lens fraction
in the M31 dark halo. We propose a series of observations with ACS
that will provide the most thorough search for microlensing toward
M87, the central elliptical galaxy of the Virgo cluster. This program
is optimized for lenses in the mass range from 0.01 to 1.0 solar
masses. By comparing with archival data, we can detect lenses as
massive as 100 solar masses, such as the remnants of the first stars.
These observations will have at least 15 times more sensitivity to
microlensing than any previous survey, e.g. using WFPC2. This is due
to the factor of 2 larger area, factor of more than 4 more sensitivity
in the I-band, superior pixel scale and longer baseline of
observations. Based on the halo microlensing results in the Milky Way
and M31, we might expect that galaxy collisions and stripping would
populate the overall cluster halo with a large number of stellar mass
objects. This program would determine definitively if such objects
compose the cluster dark matter at the level seen in the Milky Way. A
negative result would indicate that such objects do not populate the
intracluster medium, and may indicate that galaxy harassment is not as
vigorous as expected. We can measure the level of events due to the
M87 halo: this would be the best exploration to date of such a lens
population in an elliptical galaxy. Star-star lensing should also be
detectable. About 20 erupting classical novae will be seen, allowing
to determine the definitive nova rate for this giant elliptical
galaxy. We will determine if our recent HST detection of an M87
globular cluster nova was a fluke, or indicative of a 100x higher rate
of incidence of cataclysmic variables and nova eruptions in globulars
than previously believed. We will examine the populations of variable
stars, and will be able to cleanly separate them from microlensing.

WFPC2 10537

Caught in the Act with HST -- Active Jet Sculpting in the Young
Preplanetary Nebulae IRAS 22036+5306

We have discovered an extended, highly-structured and bipolar nebula
surrounding the post- AGB object IRAS22036+5306 {I22036}, in a Cycle
10 WFPC2 imaging survey of very young pre- planetary nebulae {PPNs}.
Young PPNs like I22036, objects in rapid transition between the AGB
and Planetary Nebulae {PN} phases, retain direct signatures, in the
spatial character of their outflows, of the physical mechanisms which
transform slowly expanding, round circumstellar AGB envelopes into
highly aspherical PNs with fast-expanding elongated lobes along one or
more axes. I22036 shows intriguing evidence for the presence of jets
in the HST images, and VLA A-array maps show OH maser emission in a
linear structure along the nebular axis. Our ground-based echelle
H-alpha spectra show high-velocity blue-shifted absorption in a very
broad {~2000 km/s} line profile, and mm-wave CO J=1-0 interferometric
data show a bipolar molecular outflow. There are very few young PPNs
like I22036 which show clear morphological & kinematical evidence of
the presence of jets and their working surfaces, making it
unquestionably a key object for understanding how jets can sculpt out
bipolar lobes in a progenitor AGB star wind. Using ground-based
long-slit spectroscopy with the Keck/ESI, we have partially spatially
resolved the H-alpha emission in this object. We now propose to image
I22036 in F658N, F631N, F606W and F814W in order to identify
accurately the location and structure of the shocked gas, and its
relation to the jets and their working surfaces. An important goal is
to determine whether we can characterise the forward and reverse
shocks near the heads of the knotty jets. The proposed HST imaging
will help us to understand the spatio- kinematic structure of the
outflowing gas in the bipolar lobes, and allow us to study the
relationships between the important dynamical components of this
nebula. Supporting ground- based observations such as Zeeman
measurements of polarised OH masers with the VLBA to search for
magnetic fields in I22036 are being pursued for testing
magnetic-collimation models for jets in PPNs.

ACS/WFC/NIC3/WFPC2 10530

Probing Evolution And Reionization Spectroscopically {PEARS}

While imaging with HST has gone deep enough to probe the highest
redshifts, e.g. the GOODS survey and the Ultra Deep Field,
spectroscopic identifications have not kept up. We propose an ACS
grism survey to get slitless spectra of all sources in a wide survey
region {8 ACS fields} up to z =27.0 magnitude, and an ultradeep field
in the HUDF reaching sources up to z =28 magnitude. The PEARS survey
will: {1} Find and spectrocopically confirm all galaxies between
z=4-7. {2} Probe the reionization epoch by robustly determining the
luminosity function of galaxies and low luminosity AGNs at z = 4 - 6.
With known redshifts, we can get a local measure of star formation and
ionization rate in case reionization is inhomogeneous. {3} Study
galaxy formation and evolution by finding galaxies in a contiguous
redshift range between 4 z 7, and black hole evolution through a
census of low-luminosity AGNs. {4} Get a robust census of galaxies
with old stellar populations at 1 z 2.5, invaluable for checking
consistency with heirarchical models of galaxy formation. Fitting
these galaxies' spectra will yield age and metallicity estimates. {5}
Study star-formation and galaxy assembly at its peak at 1 z 2 by
identifying emission lines in star-forming galaxies, old populations
showing the 4000A break, and any combination of the two. {6} Constrain
faint white dwarfs in the Galactic halo and thus measure their
contribution to the dark matter halo. {7} Derive spectro-photometric
redshifts by using the grism spectra along with broadband data. This
will be the deepest unbiased spectroscopy yet, and will enhance the
value of the multiwavelength data in UDF and the GOODS fields to the
astronomical community. To this end we will deliver reduced spectra to
the HST archives.

ACS/HRC 10525

Characterizing the Near-UV Environment of M Dwarfs: Implications for
Extrasolar Planetary Searches and Astrobiology

We propose SNAP observations with the ACS HRC PR200L prism, designed
to measure the near ultraviolet emission in a sample of 107 nearby M
dwarfs. The sample spans the mass range from 0.1 - 0.6 solar masses
{temperature range 2200K - 4000K} where the UV energy distributions
vary widely between active and inactive stars. The strength and
distribution of this UV emission can have critical consequences for
the atmospheres of attendant planets. Our proposed observations will
provide desperately needed constraints on models of the habitability
zone and the atmospheres of possible terrestrial planets orbiting M
dwarf hosts, and will be used to sharpen TPF target selection. In
addition, the NUV data will be used in conjunction with existing
optical, FUV and X-ray data to constrain a new generation of M dwarf
atmospheric models, and to explore unanswered questions regarding the
dynamo generation and magnetic heating in these low-mass stars.

ACS/WFC 10523

The Halo Shape and Metallicity of Massive Spiral Galaxies

We propose to resolve the stellar populations of the halos of seven
nearby, massive disk galaxies using a SNAP survey with WFC/ACS. These
observations will provide star counts and color-magnitude diagrams 2-3
magnitudes below the tip of the Red Giant Branch along the two
principal axes and one intermediate axis of each galaxy. We will
measure the metallicity distribution functions and stellar density
profiles from star counts down to very low average surface
brightnesses, equivalent to ~31 V-mag per square arcsec. This proposal
will create a unique sampling of galaxy halo properties, as our
targets cover a range in galaxy mass, luminosity, inclination, and
morphology. As function of these galaxy properties this survey will
provide:- the first systematic measurement of radial light profiles
and axial ratios of the diffuse stellar halos and outer disks of
spiral galaxies- a comprehensive analysis of halo metallicity
distributions as function of galaxy type and position within the
galaxy- an unprecedented study of the stellar metallicity and age
distribution in the outer disk regions where the disk truncations
occur- the first comparative study of globular clusters and their
field stellar populations We will use these fossil records of the
galaxy assembly process to test halo formation models within the
hierarchical galaxy formation scheme.

NIC3/ACS/WFC 10504

Characterizing the Sources Responsible for Cosmic Reionization

Our group has demonstrated the role that massive clusters, acting as
powerful cosmic lenses, can play in constraining the abundance and
properties of low-luminosity star-forming sources beyond z~6; such
sources are thought to be responsible for ending cosmic reionization.
The large magnification possible in the critical regions of
well-constrained clusters brings sources into view that lie at or
beyond the limits of conventional exposures such as the UDF, as well
as those in imaging surveys being undertaken with IRAC onboard
Spitzer. We have shown that the combination of HST and Spitzer is
particularly effective in delivering the physical properties of these
distant sources, constraining their mass, age and past star formation
history. Indirectly, we therefore gain a valuable glimpse to yet
earlier epochs. Recognizing the result {and limitations} of the UDF
exposure, we propose a systematic search through 6 lensing clusters
with ACS and NICMOS for further z~6-7 sources in conjunction with
existing deep IRAC data. Our survey will mitigate cosmic variance and
extend the search both to lower luminosities and, by virtue of the
NICMOS/IRAC combination, to higher redshift. The goal is to count and
characterize representative sources at z~6-10 and to delineate the
redshift range of activity for the planning of future observations.

ACS/WFC 10497

Cepheid Calibrations of the Luminosity of Two Reliable Type Ia
Supernovae and a Re- determination of the Hubble Constant

We propose to determine the luminosity of two type Ia supernovae {SNe
Ia}, 1995al in NGC 3021 and SN 2002fk in NGC 1309, by observing
Cepheids in their spiral hosts. Modern CCD photometry yields an
extremely tight Hubble diagram for SNe Ia with a precisely determined
intercept {i.e., Delta H_0/H_0}. Yet, the measurement of the true
Hubble constant via SNe Ia is limited by the calibration derived from
problematic and unreliable SN data. Most of the SNe Ia calibrated by
HST to date are significantly compromised by the systematics of
photographic photometry, high reddening and SN peculiarity, and by the
photometric anomolies associated with WFPC2. The extended reach of ACS
now provides opportunities to more reliably calibrate SNe Ia and H_0.
Our Cepheid calibration of a reliable SN Ia dataset, SN 1994ae, using
ACS in Cycle 11 resulted in a 15% increase in H_0 from the value
derived by the HST SN Ia Calibration Program. Yet, there remains a
terribly small sample of reliable SN Ia data sets on which to base
such a crucial cosmological result. SN 1995al and SN 2002fk are two of
the best observed SNe Ia both with little reddening. They provide two
opportunities to use ACS for placing the calibration of H_0 via SN Ia
on firmer footing and potentially improve its precision.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily pre-
scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.

ACS/WFC 10101

The Region of the Hydrogen-Burning Limit in Omega Centauri and 47
Tucanae

We propose a photometric study of the lower main sequences of Omega
Cen and 47 Tuc, down to the region of the H-burning limit, which the
deeper faintness limit of ACS will allow us to reach. For the faintest
stars, proper-motion separation of cluster from field is essential;
hence we include Cycle 13 observations. The resulting color--magnitude
diagrams {CMDs} and luminosity functions {LFs} will allow study of
stars in a mass regime and metallicity that have never been accessible
before, and will serve as an important check on theories of the
structure of low- mass stars. These are the 2nd-epoch observations.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

10062 - GSacq (2,3,2) failed due to search radius limit exceeded @
357/1648z GSacq(2,3,2) scheduled at 357/16:45:04 failed due to search
radius limit exceeded on FGS 3. A ESB a07( FGS Coarse Track failed -
Timed out waiting for data valid) was also received. OBAD1 showed
errors of V1=871.76, V2=-1732.12, V3=18.03, RSS=1939.21. OBAD2 showed
errors of V1=11.25, V2=2.31, V3=0.53, RSS=11.50.

10063 - GSAcq (2,1,2) failed due to search radius limit exceeded on
FGS 2 @ 358/2314z At AOS @ 358/23:37:00 indications showed that GSAcq
(2,1,2) scheduled @ 358/23:14:37 had failed due to search radius
limit exceeded. 486 ESB "a05" Exceeded SRL was received @ AOS. OBAD 1
@ 22:58:40 showed the following errors: V1 -340.86, V2 -2040.09, V3
74.13, RSS 2069.69 OBAD 2 unavailable due to LOS OBAD MAP scheduled @
23:21:42 showed the following errors at AOS: V1 1.58, V2 164.96, V3
4.50, RSS 165.03

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS
GSacq 31 29 357/1648z
(HSTAR 10062)
358/2314z
(HSTAR 10063)
FGS REacq 29 29
OBAD with Maneuver 114 114

SIGNIFICANT EVENTS: (None)