Daily Report #4588

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** # 4588

PERIOD COVERED: UT April 11,12,13, 2008 (DOY 102,103,104)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration - CR Persistence Part 6

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 11312

The Local Cluster Substructure Survey {LoCuSS}: Deep Strong Lensing
Observations with WFPC2

LoCuSS is a systematic and detailed investigation of the mass,
substructure, and thermodynamics of 100 X-ray luminous galaxy clusters
at 0.15z0.3. The primary goal is to test our recent suggestion that
this population is dominated by dynamically immature disturbed
clusters, and that the observed mass-temperature relation suffers
strong structural segregation. If confirmed, this would represent a
paradigm shift in our observational understanding of clusters, that
were hitherto believed to be dominated by mature, undisturbed systems.
We propose to complete our successful Cycle 15 program {SNAP:10881}
which prior to premature termination had delivered robust weak-lensing
detections in 17 clusters, and candidate strongly-lensed arcs in 11 of
these 17. These strong and weak lensing signals will give an accurate
measure of the total mass and structure of the dark matter
distribution that we will subsequently compare with X-ray and Sunyaev
Zeldovich Effect observables. The broader applications of our project
include 1} the calibration of mass-temperature and mass-SZE scaling
relations which will be critical for the calibration of proposed dark
energy experiments, and 2} the low redshift baseline study of the
demographics of massive clusters to aid interpretation of future high
redshift {z1} cluster samples. To complete the all-important high
resolution imaging component of our survey, we request deep WFPC2
observations of 20 clusters through the F606W filter, for which
wide-field weak-lensing data are already available from our Subaru
imaging program. The combination of deep WFPC2 and Subaru data for
these 20 clusters will enable us to achieve the science program
approved by the Cycle 15 TAC.

WFPC2 11235

HST NICMOS Survey of the Nuclear Regions 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
NICMOS NIC2 imaging of the nuclear regions 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 and resolution of NICMOS NIC2 on HST enables a unique
opportunity to study the detailed structure of the nuclear regions,
where dust obscuration may mask star clusters, AGN and additional
nuclei from optical view, with a resolution significantly higher than
possible with Spitzer IRAC. This survey thus provides a crucial
component to our study of the dynamics and evolution of IR galaxies
presently underway with Wide-Field, HST ACS/WFC and Spitzer IRAC
observations of these 88 galaxies. Imaging will be done with the F160W
filter {H-band} to examine as a function of both luminosity and merger
stage {i} the luminosity and distribution of embedded star clusters,
{ii} the presence of optically obscured AGN and nuclei, {iii} the
correlation between the distribution of 1.6 micron emission and the
mid- IR emission as detected by Spitzer IRAC, {iv} the evidence of
bars or bridges that may funnel fuel into the nuclear region, and {v}
the ages of star clusters for which photometry is available via
ACS/WFC observations. The NICMOS data, combined with the HST ACS,
Spitzer, and GALEX observations of this sample, will result in the
most comprehensive study of merging and interacting galaxies to date.

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.

NIC3 11195

Morphologies of the Most Extreme High-Redshift Mid-IR-luminous
Galaxies II: The `Bump' Sources

The formative phase of some of the most massive galaxies may be
extremely luminous, characterized by intense star- and AGN-formation.
Till now, few such galaxies have been unambiguously identified at high
redshift, and thus far we have been restricted to studying the
low-redshift ultraluminous infrared galaxies as possible analogs. We
have recently discovered a sample of objects which may indeed
represent this early phase in galaxy formation, and are undertaking an
extensive multiwavelength study of this population. These objects are
optically extremely faint {R26} but nevertheless bright at
mid-infrared wavelengths {F[24um] 0.5 mJy}. Mid-infrared
spectroscopy with Spitzer/IRS reveals that they have redshifts z~2,
implying luminosities ~1E13 Lsun. Their mid-IR SEDs fall into two
broad, perhaps overlapping, categories. Sources with brighter F[24um]
exhibit power-law SEDs and SiO absorption features in their mid-IR
spectra characteristic of AGN, whereas those with fainter F[24um] show
a "bump" characteristic of the redshifted 1.6um peak from a stellar
population, and PAH emission characteristic of starformation. We have
begun obtaining HST images of the brighter sources in Cycle 15 to
obtain identifications and determine kpc-scale morphologies for these
galaxies. Here, we aim to target the second class {the "bump" sources}
with the goal of determining if these constitute morphologically
different objects, or simply a "low-AGN" state of the brighter class.
The proposed observations will help us determine whether these objects
are merging systems, massive obscured starbursts {with obscuration on
kpc scales!} or very reddened {locally obscured} AGN hosted by
intrinsically low-luminosity galaxies.

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.

NIC2/NIC1/NIC3 11159

The True Galactic Bulge Luminosity Function

We propose to obtain second epoch imaging of the deep Galactic bulge
field observed using NICMOS by Zoccali et al. (2000). The bulge
luminosity and mass function suffered from 30-50% contamination by
foreground disk stars, which was impossible to correct for in the
original study. Revisiting the field after 9 years, we propose to
segregate the foreground disk stars because they have large transverse
velocities, thus revealing the luminosity function of Galactic bulge
low mass stars to near the hydrogen burning limit. The slope of the
mass function has implications for galaxy formation and for
understanding the nature of microlensing in the Galactic bulge.

NIC3 11149

Characterizing the Stellar Populations in Lyman-Alpha Emitters and
Lyman Break Galaxies at 5.7z7 in the Subaru Deep Field

The epoch of reionization marks a major phase transition of the
Universe, during which the intergalactic space became transparent to
UV photons. Determining when this occurred and the physical processes
involved represents the latest frontier in observational cosmology.
Over the last few years, searches have intensified to identify the
population of high-redshift (z6) galaxies that might be responsible
for this process, but the progress is hampered partly by the
difficulty of obtaining physical information (stellar mass, age, star
formation rate/history) for individual sources. This is because the
number of z6 galaxies that have both secure spectroscopic redshifts
and high-quality infrared photometry (especially with Spitzer/IRAC) is
still fairly small. Considering that only several photometric points
are available per source, and that many model SEDs are highly
degenerate, it is crucial to obtain as many observational constraints
as possible for each source to ensure the validity of SED modeling. To
better understand the physical properties of high-redshift galaxies,
we propose here to conduct HST/NICMOS (72 orbits) and Spitzer/IRAC
(102 hours) imaging of spectroscopically confirmed, bright (z26 mag
(AB)) Ly-alpha emitters (LAEs) and Lyman-break galaxies (LBGs) at
5.7z7 selected from the Subaru Deep Field. Spectroscopic redshifts
remove one critical free parameter from SED modeling while bright
source magnitudes ensure high-quality photometric data. By making
accurate determinations of stellar masses, ages, and star-formation
histories, we will specifically address the following major questions:
(1) Do LAEs and LBGs represent physically different galaxy populations
at z6 as suggested recently? (2) Is Ly-alpha emission systematically
suppressed at z6 with respect to continuum emission? (i.e., are we
reaching the epoch of incomplete reionization?), and (3) Do we see any
sign of abnormally young stellar population in any of the z6
galaxies?

NIC2 11143

NICMOS imaging of submillimeter galaxies with CO and PAH redshifts

We propose to obtain F110W and F160W imaging of 10 z~2.4 submillimeter
galaxies {SMGs} whose optical redshifts have been confirmed by the
detection of millimeter CO and/or mid- infrared PAH emission. With the
4000A break falling within/between the two imaging filters, we will be
able to study these sources' spatially resolved stellar populations
{modulo extinction} in the rest-frame optical. SMGs' large
luminosities appear to be due largely to merger-triggered starbursts;
high-resolution NICMOS imaging will help us understand the stellar
masses, mass ratios, and other properties of the merger progenitors,
valuable information in the effort to model the mass assembly history
of the universe.

NIC1/NIC2 11139

NICMOS Observations of the Microquasar GRS 1758-258

The galactic black hole candidate GRS 1758-258 is normally one of the
brightest persistent gamma-ray sources in the vicinity of the galactic
center. It is a microquasar with relativistic radio jets emanating
from a central variable source. Microquasars are excellent nearby test
laboratories for studying the complex accretion and outflow processes
that take place near black hole horizons. Despite an accurate location
provided by Chandra and the VLA and over a decade of careful
ground-based studies, the optical/infrared counterpart to GRS 1758-258
remains unknown. A stellar counterpart is expected, but the current
candidates are all more than 2 sigma from the center of the error
circle. The ground-based infrared flux limits are also right at the
values expected for the synchrotron emission from the outflow from the
black hole, and possibly for the emission from the accretion disk.
This leaves open the question as to what is powering this very
energetic persistent source. Here we propose to use NICMOS to perform
broad-band imaging of the GRS 1758- 258 error box. These images will
be more than three magnitudes more sensitive than the current
ground-based ones. The resulting spectra will reveal the thermal/non-
thermal nature of the sources in the region of the error box, and the
high spatial resolution images may reveal a jet structure. We propose
to perform three visits of two orbits each spanning the suggested
18.45 day binary orbital period of the system: a correct counterpart
identification should be confirmed by its variability. We will also
aim to support the HST observations with X- and gamma-ray observations
using Swift or INTEGRAL, and with longer wavelength observations from
the ground.

NIC3 11120

A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic
Center

The Galactic center (GC) is a unique site for a detailed study of a
multitude of complex astrophysical phenomena, which may be common to
nuclear regions of many galaxies. Observable at resolutions
unapproachable in other galaxies, the GC provides an unparalleled
opportunity to improve our understanding of the interrelationships of
massive stars, young stellar clusters, warm and hot ionized gases,
molecular clouds, large scale magnetic fields, and black holes. We
propose the first large-scale hydrogen Paschen alpha line survey of
the GC using NICMOS on the Hubble Space Telescope. This survey will
lead to a high resolution and high sensitivity map of the Paschen
alpha line emission in addition to a map of foreground extinction,
made by comparing Paschen alpha to radio emission. This survey of the
inner 75 pc of the Galaxy will provide an unprecedented and complete
search for sites of massive star formation. In particular, we will be
able to (1) uncover the distribution of young massive stars in this
region, (2) locate the surfaces of adjacent molecular clouds, (3)
determine important physical parameters of the ionized gas, (4)
identify compact and ultra-compact HII regions throughout the GC. When
combined with existing Chandra and Spitzer surveys as well as a wealth
of other multi-wavelength observations, the results will allow us to
address such questions as where and how massive stars form, how
stellar clusters are disrupted, how massive stars shape and heat the
surrounding medium, and how various phases of this medium are
interspersed.

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.

WFPC2 11099

A "silver bullet" for the sources of reionization

Recent discoveries of z6 galaxies have given us the first glimpse of
the Universe shortly after the era of reionization. The questions
arose whether these first galaxies can be made responsible for the
reionization process, and how long did it last. Neither observations
nor theory provide a clean answer. In particular observations give
results that are barely mutually consistent and need to be further
tested. Observing high redshift (z7) sources is in general difficult,
mostly due to the high luminosity distance to these objects, and
partly due to the lower expected stellar masses compared to objects at
moderate redshifts.

We propose to use one of the most massive, merging cluster 1E0657-56
(z=0.295) as a cosmic telescopes to efficiently probe the
high-redshift universe. The gravitational potential well of this
cluster provides several magnitudes of magnification, enabling study
of intrinsically lower luminosity galaxies.As we discuss in the
proposal, due to its highly elongated mass distribution and ideal
redshift the bullet cluster is a prime candidate for this study. We
propose deep NICMOS and WFPC2 observations; with much reduced
observing time compared to e.g. NICMOS UDF we expect an order of
magnitude more (~5 candidates) z7 objects. They will also likely be
multiply imaged, and since the geometry of images depends upon the
redshift, we will be able to confirm their nature, thereby not
requiring (often prohibitive at these magnitudes) spectroscopic
follow-up. This will enable us to count high-redshift sources and
constrain their luminosity function; a task made possible with the
help of gravitational lensing even in the pre-JWST era.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11249 - GSacq(2,1,2) failed to RGA control. @ 102/1514z

During LOS GSaq(2,1,2) scheduled at 102/15:14:50 failed to RGA
control. The GSacq failed due to receiving stop flag QF2STOPF on FGS
2. The Map at 15:23:32 showed errors of V1=17.15, V2=9.04, V3=3.75,
and RSS=19.75.

11252 - OBAD Failed Identification (ESB 1902) @ 104/1625z

At Acquisition of Signal (104/16:25:46) received three (3) 486 STB ESB
1902 "OBAD Failed ID" messages. Vehicle was in RGA control, M2G mode
with OBAD flag mnemonics showing GOBSTAT=255 (Attitude Determination
Error) and GCHACL09=1 or (Failed State). OBAD Map at 15:40:16 showed
errors of: V1 -32245.59, V2 6342.19, V3 -51499.65, RSS 61091.86
arc-seconds. The GSAcquisition at 15:32:59 was not attempted as the
#44 commands had not updated. Ops Request 17543-2 was successfully
executed and copies of the dump for tables 369 & 370 are attached.
Awaiting next available engineering data dump to perform further
analysis.

11253 - GSAcq (2,3,3) results in RGA Control @ 104/1625z

At Acquisition of Signal (104/16:25:46) GSAcq (2,3,3) scheduled from
(15:32:59-15:40:16) had not attempted due to both pre-acquisition
OBAD's failing. GSAcq #44 commands did not update. OBAD #1 RSS error
was 61102.55 arc-seconds. OBAD #2 RSS error was 56101.50 arc-seconds.
OBAD Map RSS error was 61091.86 arc-seconds.

COMPLETED OPS REQUEST:

17543-2 - Dump OBAD tables after failed OBAD (Generic) @ 104/1643z

COMPLETED OPS NOTES: (None)

*********************** SCHEDULED***** SUCCESSFUL

FGS GSacq************** 23****************** 21
FGS REacq************** 11***************** 11
OBAD with Maneuver **** 70****************** 68

SIGNIFICANT EVENTS:

Flash Report: FGS ITS Test

The ITS tests scheduled from 105:02:42 - 105:06:00 performed as
expected. The first ITS test was monitored in real time and no
anomalous behavior was seen. The other ITS tests occurred in ZOEs and
the data will be looked at when it is merged. There were no problems
indicated in telemetry when telemetry was reacquired after the tests
were performed. The subsequent guide star acquisitions have all been
successful.

All SSR ENG data was dumped at 105/0749z