Daily Report # 4341

Notice: For the foreseeable future, the daily reports may contain apparent
discrepancies between some proposal descriptions and the listed instrument
usage. This is due to the conversion of previously approved ACS WFC or HRC
observations into WFPC2, or NICMOS observations subsequent to the loss of
ACS CCD science capability in late January.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4341

PERIOD COVERED: UT April 13,14,15, 2007 (DOY 103,104,105)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration - CR Persistence Part 6

A new proceedure proposed to alleviate the CR-persistence problem of NICMOS.
Dark frames will be obtained immediately upon exiting the SAA contour 23,
and everytime 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 i mages. Each observation will need its own CRMAP, as
different SAA passages leave different imprints on the NICMOS detectors.

WFPC2 11085

Europa in Eclipse: Tenuous Atmosphere, Electromagnetic Activity and Surface
Luminescence

HST Proposal 11085 We propose to image Europa during its orbital eclipse by
Jupiter. This will form the basis of an investigation into the nature of the
tenuous atmosphere, electromagnetic environment and surface material of
Europa. We will compare the FUV oxygen line at 1356A to the optical line at
6300A and seek optical auroral hydrogen emission in Halpha. With broad
continuum filters, we will search for optical emissions from other
atmospheric constituents and for fluorescence of the surface material,
arising from the very high level of incident energetic particle radiation.
The high spatial resolution of ACS will allow us to fully resolve scales of
interest and allow us to distinguish easily the different terrains on
Europa's surface. In particular we wish to compare luminesence in regions
dominated by ice to those of potentially organic red material.

WFPC2 11083

The Structure, Formation and Evolution of Galactic Cores and Nuclei

A surprising result has emerged from the ACS Virgo Cluster Survey {ACSVCS},
a program to obtain ACS/WFC gz imaging for a large, unbiased sample of 100
early-type galaxies in the Virgo Cluster. On subarcsecond scales {i.e.,
0.1"-1"}, the HST brightness profiles vary systematically from the
brightest giants {which have nearly constant surface brightness cores} to
the faintest dwarfs {which have compact stellar nuclei}. Remarkably, the
fraction of galaxy mass contributed by the nuclei in the faint galaxies is
identical to that contributed by supermassive black holes in the bright
galaxies {0.2%}. These findings strongly suggest that a single mechanism is
responsible for both types of Central Massive Object: most likely internally
or externally modulated gas inflows that feed central black holes or lead to
the formation of "nuclear star clusters". Understanding the history of gas
accretion, star formation and chemical enrichment on subarcsecond scales has
thus emerged as the single most pressing question in the study of nearby
galactic nuclei, either active or quiescent. We propose an ambitious HST
program {199 orbits} that constitutes the next, obvious step forward:
high-resolution, ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W} imaging
for the complete ACSVCS sample. By capitalizing on HST's unique ability to
provide high-resolution images with a sharp and stable PSF at UV and IR
wavelengths, we will leverage the existing optical HST data to obtain the
most complete picture currently possible for the history of star formation
and chemical enrichment on these small scales. Equally important, this
program will lead to a significant improvement in the measured structural
parameters and density distributions for the stellar nuclei and the
underlying galaxies, and provide a sensitive measure of "frosting" by young
stars in the galaxy cores. By virtue of its superb image quality and stable
PSF, NICMOS is the sole instrument capable of the IR observations proposed
here. In the case of the WFPC2 observations, high-resolution UV imaging {
0.1"} is a capability unique to HST, yet one that could be lost at any any
time.

NIC3 11082

NICMOS Imaging of GOODS: Probing the Evolution of the Earliest Massive
Galaxies, Galaxies Beyond Reionization, and the High Redshift Obscured
Universe

Deep near-infrared imaging provides the only avenue towards understanding a
host of astrophysical problems, including: finding galaxies and AGN at z
7, the evolution of the most massive galaxies, the triggering of star
formation in dusty galaxies, and revealing properties of obscured AGN. As
such, we propose to observe 60 selected areas of the GOODS North and South
fields with NICMOS Camera 3 in the F160W band pointed at known massive M
10^11 M_0 galaxies at z 2 discovered through deep Spitzer imaging. The
depth we will reach {26.5 AB at 5 sigma} in H_160 allows us to study the
internal properties of these galaxies, including their sizes and
morphologies, and to understand how scaling relations such as the Kormendy
relationship evolved. Although NIC3 is out of focus and undersampled, it is
currently our best opportunity to study these galaxies, while also sampling
enough area to perform a general NIR survey 1/3 the size of an ACS GOODS
field. These data will be a significant resource, invaluable for many other
science goals, including discovering high redshift galaxies at z 7, the
evolution of galaxies onto the Hubble sequence, as well as examining
obscured AGN and dusty star formation at z 1.5. The GOODS fields are the
natural location for HST to perform a deep NICMOS imaging program, as
extensive data from space and ground based observatories such as Chandra,
GALEX, Spitzer, NOAO, Keck, Subaru, VLT, JCMT, and the VLA are currently
available for these regions. Deep high-resolution near-infrared observations
are the one missing ingredient to this survey, filling in an important gap
to create the deepest, largest, and most uniform data set for studying the
faint and distant universe. The importance of these images will increase
with time as new facilities come on line, most notably WFC3 and ALMA, and
for the planning of future JWST observations.

ACS/SBC 11074

ACS/SBC Darks in Support of Specific SBC Science Observations

This program provides SBC DARK visits to be scheduled in conjuction with
certain specific science observations which require the SBC to be turned on
in the orbit preceeding the science observation.

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.

WFPC2 11031

CTE Background Dependence Closeout

Measuring the charge transfer efficiency {CTE} of an astronomical CCD camera
is crucial to determining the CCD's photometric fidelity across the field of
view. WFPC2's CTE has degraded steadily over the last 13 years because of
continuous exposure to trapped particles in HST's radiation environment. The
fraction of photometric signal lost from WFPC2's CTI {charge transfer
inefficiency} is a function of WFPC2's time in orbit, the integrated signal
in the image, the location of the image on the CCD, and the background
signal. Routine monitoring of WFPC2's CTE over the last 13 years permits an
assessment of all but the last condition. The dependence of CTE on
background signal must be characterized, however, because a large fraction
of WFPC2 images have been obtained under conditions of significant sky
background. This program aims to assess the end-of-life CTE of WFPC2's CCDs
separately as a function of background signal. Traditional images of an
off-center field in NGC 5139 {Omega Cen} are recorded after preflashing {or
before postflashing} the CCDs with internal lamps to provide average
background signals of 0-160 e-, which span the range of sky backgrounds
observed in ~99% of long-exposure narrow- and broad-band WFPC2 images.

ACS/SBC 10907

Testing the first direct measurement of cataclysmic variable evolution: the
search for a circumbinary disk or a low?mass companion around NN Serpentis

We obtained high time-resolution photometry using the high speed CCD camera
ULTRACAM between 2002 and 2004, which revealed a gradual reduction in the
orbital period of the pre- cataclysmic variable NN Serpentis. There are
three possible explanations for this period change: firstly, we may have
been successful in obtaining the first and only direct measurement of the
braking rate of a close binary system, in which case our measured values are
approximately 2 orders of magnitude greater than predicted, and pose serious
problems for the theory of close binary evolution. Secondly, the unusually
high braking rate may be caused by the presence of a circumbinary disk,
which would help to answer two of the outstanding problems with current CV
theory - namely the high mass- transfer rates seen in some CVs, and the fact
that the minimum observed value in the CV period distribution is
approximately 15% longer than expected. Finally, our observations could be
explained by a light travel-time effect caused by a third body in orbit
around the binary, which would raise major questions about the evolutionary
history of the system, in particular how a third body has managed to remain
in a stable orbit throughout periods of intense mass-loss in the central
binary. We intend to use IRAC observations to search for a mid-infrared
excess in the spectral energy distribution of NN Ser, which would confirm
the presence of either a disk or a third body. We then propose to use HST
imaging to attempt to resolve a third body, allowing us to discriminate
between the two possibilities. If both methods fail to reveal any extra
system components, we will have ruled out our only remaining alternatives to
a genuinely high angular momentum loss rate in this system, with profound
implications for CV evolution.

WFPC2 10890

Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies

The formative phase 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, restricting us
to the study of 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 bright
at mid-IR wavelengths {F[24um]0.8mJy}, but deep ground based imaging
suggests extremely faint {and in some cases extended} optical counterparts
{R~24-27}. Deep K-band images show barely resolved galaxies. Mid-infrared
spectroscopy with Spitzer/IRS reveals that they have redshifts z ~ 2-2.5,
suggesting bolometric luminosities ~10^{13-14}Lsun! We propose to obtain
deep ACS F814W and NIC2 F160W images of these sources and their environs in
order to determine kpc-scale morphologies and surface photometry for these
galaxies. The proposed observations will help us determine whether these
extreme 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 10880

The host galaxies of QSO2s: AGN feeding and evolution at high luminosities

Now that the presence of supermassive black holes in the nuclei of galaxies
is a well established fact, other questions related to the AGN phenomena
still have to be answered. Problems of particular interest are how the AGN
gets fed, how the black hole evolves and how the evolution of the black hole
is related to the evolution of the galaxy bulge. Here we propose to address
some of these issues using ACS/WFC + F775W snapshot images of 73 QSO2s with
redshifts in the range 0.3z0.4. These observations will be combined with
similar archival data of QSO1s and ground based data of Seyfert and normal
galaxies. First, we will intestigate whether interactions are the most
important feeding mechanism in high luminosity AGNs. This will be done in a
quantitative way, comparing the asymmetry indices of QSO2 hosts with those
of lower luminosity AGNs and normal galaxies. Second, we will do a detailed
study of the morphology of the host galaxies of both QSO types, to determine
if they are similar, or if there is an evolutionary trend from QSO2s to
QSO1s. The results from this project will represent an important step in the
understanding of AGN evolution, and may also introduce a substantial
modification to the Unified Model.

WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for
supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS},
have found hundreds of SNe, many of them in quite nearby galaxies {cz 4000
km/s}. Most of the objects were discovered before maximum brightness, and
have follow-up photometry and spectroscopy; they include some of the
best-studied SNe to date. We propose to conduct a snapshot imaging survey of
the sites of some of these nearby objects, to obtain late-time photometry
that {through the shape of the light and color curves} will help reveal the
origin of their lingering energy. The images will also provide
high-resolution information on the local environments of SNe that are far
superior to what we can procure from the ground. For example, we will obtain
color-color and color-magnitude diagrams of stars in these SN sites, to
determine the SN progenitor masses and constraints on the reddening.
Recovery of the SNe in the new HST images will also allow us to actually
pinpoint their progenitor stars in cases where pre- explosion images exist
in the HST archive. This proposal is an extension of our successful Cycle 13
snapshot survey with ACS. It is complementary to our Cycle 15 archival
proposal, which is a continuation of our long-standing program to use
existing HST images to glean information about SN environments.

WFPC2 10873

The Radio-quiet Jet Flow in Markarian 34

The properties of AGN jet flows are notoriously difficult to ascertain. We
are currently studying jets in Seyferts by combining emission-line
diagnostics with radio observations. We have devised a method of analysis
which -- with only modest and reasonable assumptions -- leads to a physical
description of the jet flow: its mass, momentum and energy flux, along with
its density, velocity and Mach number. We have applied this method to a rich
dataset on Markarian 78 and discovered that its jet is very weak, slow, and
dense relative to the kind of jets found in radio loud AGN {Whittle \&
Wilson 2004, Whittle et al 2005, 2006}. Such a difference between radio
quiet and radio loud jet flows would be a major result -- if it were found
to be generally true. We have more modest observations of a further six
Seyferts with jets, but only one of these -- Mkn 34 -- approaches Mkn 78 as
a clean enough case to allow our full analysis. Our existing VLA and STIS
data are excellent, but the HST archive emission-line and continuum images
are of poor quality and low resolution. We are requesting just 3 orbits to
obtain higher S/N images at high resolution {ACS/HRC} in [OIII] 5007, [OII]
3727, green and red continuum, bringing the total dataset up to a par with
that of Mkn 78. We will then be able to apply our full analysis to determine
the nature of the jet flow in this second radio quiet AGN.

ACS/SBC 10872

Lyman Continuum Emission in Galaxies at z=1.2

Lyman continuum photons produced in massive starbursts may have played a
dominant role in the reionization of the Universe. Starbursts are important
contributors to the ionizing metagalactic background at lower redshifts as
well. However, their contribution to the background depends upon the
fraction of ionizing radiation that escapes from the intrinsic opacity of
galaxies below the Lyman limit. Current surveys suggest escape fractions of
a few percent, up to 10%, with very few detections {as opposed to upper
limits} having been reported. No detections have been reported in the epochs
between z=0.1 and z=2. We propose to measure the fraction of escaping Lyman
continuum radiation from 15 luminous z~1.2 galaxies in the GOODS fields.
Using the tremendous sensitivity of the ACS Solar- blind Channel, we will
reach AB=30 mag., allowing us to detect an escape fraction of 1%. We will
correlate the amount of escaping radiation with the photometric and
morphological properties of the galaxies. A non-detection in all sources
would imply that QSOs provide the overwhelming majority of ionizing
radiation at z=1.3, and it would strongly indicate that the properties of
galaxies at higher redshift have to be significantly different for galaxies
to dominate reionization. The deep FUV images will also be useful for
extending the FUV study of other galaxies in the GOODS fields.

ACS/SBC 10862

Comprehensive Auroral Imaging of Jupiter and Saturn during the International
Heliophysical Year

A comprehensive set of observations of the auroral emissions from Jupiter
and Saturn is proposed for the International Heliophysical Year in 2007, a
unique period of especially concentrated measurements of space physics
phenomena throughout the solar system. We propose to determine the physical
relationship of the various auroral processes at Jupiter and Saturn with
conditions in the solar wind at each planet. This can be accomplished with
campaigns of observations, with a sampling interval not to exceed one day,
covering at least one solar rotation. The solar wind plasma density
approaching Jupiter will be measured by the New Horizons spacecraft, and a
separate campaign near opposition in May 2007 will determine the effect of
large-scale variations in the interplanetary magnetic field {IMF} on the
Jovian aurora by extrapolation from near-Earth solar wind measurements. A
similar Saturn campaign near opposition in Jan. 2007 will combine
extrapolated solar wind data with measurements from a wide range of
locations within the Saturn magnetosphere by Cassini. In the course of
making these observations, it will be possible to fully map the auroral
footprints of Io and the other satellites to determine both the local
magnetic field geometry and the controlling factors in the electromagnetic
interaction of each satellite with the corotating magnetic field and plasma
density. Also in the course of making these observations, the auroral
emission properties will be compared with the properties of the near-IR
ionospheric emissions {from ground-based observations} and non thermal radio
emissions, from ground-based observations for Jupiter?s decametric radiation
and Cassini plasma wave measurements of the Saturn Kilometric Radiation
{SKR}.

NIC3 10839

The NICMOS Polarimetric Calibration

Recently, it has been shown that NICMOS possesses an instrumental
polarization at a level of 1.2%. This completely inhibits the data reduction
in a number of previous GO programs, and hampers the ability of the
instrument to perform high accuracy polarimetry. In all, 90 orbits of HST
data are affected, with potentially many more in Cycle 15. We propose to
obtain high signal to noise observations of three polarimetric standards at
the cardinal roll angles of the NICMOS polarizers for both NIC1 and NIC2.
These observations are designed to fully characterize the instrumental
polarization in order for NICMOS to reach its full potential by enabling
high accuracy polarimetry of sources with polarizations around 1%. The
residual polarization will also be determined as a function of position and
spectral energy distribution. Our group will rapidly turn around the
required data products and produce reports and software for the accurate
representation of the instrumental polarization. These items will be
presented to STScI and for dissemination among the wider astronomical
community.

WFPC2 10829

Secular Evolution at the End of the Hubble Sequence

The bulgeless disk galaxies at the end of the Hubble Sequence evolve at a
glacial pace relative to their more violent, earlier-type cousins. The
causes of their internal, or secular evolution are important because secular
evolution represents the future fate of all galaxies in our accelerating
Universe and is a key ingredient to understanding galaxy evolution in
lower-density environments at present. The rate of secular evolution is
largely determined by the stability of the cold ISM against collapse, star
formation, and the buildup of a central bulge. Key diagnostics of the ISM's
stability are the presence of compact molecular clouds and narrow dust
lanes. Surprisingly, edge-on, pure disk galaxies with circular velocities
below 120 km/s do not appear to contain such dust lanes. We propose to
obtain ACS/WFC F606W images of a well-selected sample of extremely late-type
disk galaxies to measure the characteristic scale size of the cold ISM and
determine if they possess the unstable, cold ISM necessary to drive secular
evolution. Our sample has been carefully constructed to include disk
galaxies above and below the critical circular velocity of 120 km/s where
the dust properties of edge-on disks change so remarkably. We will then use
surface brightness profiles to search for nuclear star clusters and
pseudobulges, which are early indicators that secular evolution is at work,
as well as measure the pitch angle of the dust lanes as a function of radius
to estimate the central mass concentrations.

ACS/SBC 10814

The Masses for ultraluminous X-ray sources

Ultraluminous X-ray sources are non-nuclear sources in normal disk galaxies
that are either stellar mass black holes that are super-Eddington emitters,
or 1E3-1E4 Msolar black holes emitting normally. We can distinguish between
these models by obtaining constraints for the mass of the primary, which can
be accomplished through UV objective prism spectra. This strategy begins
with the optical identification of the secondary and identification of its
spectral type in order to determine its mass and the Roche Lobe radius.
Secondly, we need to determine whether an accretion disk is present and if
its high ionization UV line luminosities point to a stellar mass black hole
or a more massive object. Finally, if the black hole is 1E3-1E4 Msolar, the
orbital velocity of the secondary is so large that a Doppler shift will be
detectable, even at the modest resolution of the prism.

WFPC2 10809

The nature of "dry" mergers in the nearby Universe

Recent studies have shown that "dry" mergers of red, bulge-dominated
galaxies at low redshift play an important role in shaping today's most
massive ellipticals. These mergers have been identified in extremely deep
ground-based images of red sequence galaxies at z ~ 0.1. The ground-based
images reach surface brightness limits of AB ~ 29, but lack the resolution
to study the morphologies of the galaxies inside the effective radius. Here
we propose to obtain ACS images of a representative sample of 40 of these
red sequence galaxies: 15 ongoing dry mergers, 15 remnants, and 10
undisturbed objects. We will measure the isophote shapes and ellipticities
of the galaxies, their dust content, morphological fine structure {shells
and ripples}, AGN content, and their location on the Fundamental Plane. By
comparing galaxies in different stages of the merging process we can
constrain the amount of gas associated with these red mergers, the effect of
active nuclei, and track structural changes. As two galaxies can be observed
in a single orbit 20 orbits are requested to observe the 40 galaxies.

WFPC2 10798

Dark Halos and Substructure from Arcs & Einstein Rings

The surface brightness distribution of extended gravitationally lensed arcs
and Einstein rings contains super-resolved information about the lensed
object, and, more excitingly, about the smooth and clumpy mass distribution
of the lens galaxies. The source and lens information can non-parametrically
be separated, resulting in a direct "gravitational image" of the inner
mass-distribution of cosmologically-distant galaxies {Koopmans 2005;
Koopmans et al. 2006 [astro-ph/0601628]}. With this goal in mind, we propose
deep HST ACS-F555W/F814W and NICMOS-F160W WFC imaging of 20 new
gravitational-lens systems with spatially resolved lensed sources, of the 35
new lens systems discovered by the Sloan Lens ACS Survey {Bolton et al.
2005} so far, 15 of which are being imaged in Cycle-14. Each system has been
selected from the SDSS and confirmed in two time- efficient HST-ACS snapshot
programs {cycle 13&14}. High-fidelity multi-color HST images are required
{not delivered by the 420s snapshots} to isolate these lensed images
{properly cleaned, dithered and extinction-corrected} from the lens galaxy
surface brightness distribution, and apply our "gravitational maging"
technique. Our sample of 35 early-type lens galaxies to date is by far the
largest, still growing, and most uniformly selected. This minimizes
selection biases and small-number statistics, compared to smaller, often
serendipitously discovered, samples. Moreover, using the WFC provides
information on the field around the lens, higher S/N and a better understood
PSF, compared with the HRC, and one retains high spatial resolution through
drizzling. The sample of galaxy mass distributions - determined through this
method from the arcs and Einstein ring HST images - will be studied to: {i}
measure the smooth mass distribution of the lens galaxies {dark and luminous
mass are separated using the HST images and the stellar M/L values derived
from a joint stellar-dynamical analysis of each system}; {ii} quantify
statistically and individually the incidence of mass-substructure {with or
without obvious luminous counter- parts such as dwarf galaxies}. Since
dark-matter substructure could be more prevalent at higher redshift, both
results provide a direct test of this prediction of the CDM hierarchical
structure-formation model.

WFPC2 10786

Rotational state and composition of Pluto's outer satellites

We propose an intricate set of observations aimed at discovering the
rotational state of the newly discovered satellites of Pluto, S/2005 P1 and
S/2005 P2. These observations will indicate if the satellites are in
synchronous rotation or not. If they are not, then the observations will
determine the rotational period or provide tight constraints on the
amplitude. The other primary goal is to extend the wavelength coverage of
the colors of the surface and allow us to constrain the surface compositions
of both objects. From these data we will also be able to significantly
improve the orbits of P1 and P2, improve the measurement of the bulk density
of Charon, and search for albedo changes on the surface of Pluto.

FGS 10612

Binary Stars in Cyg OB2: Relics of Massive Star Formation in a Super-Star
Cluster

We propose to make a high angular resolution SNAP survey of the massive
stars in the nearby, super-star cluster Cyg OB2. We will use FGS1r TRANS
mode observations to search for astrometric companions in the separation
range of 0.01 to 1.00 arcsec and in the magnitude difference range smaller
than 4 magnitudes. The observations will test the idea that the formation of
very massive stars involves mergers and the presence of nearby companions.
Discovery of companions to massive stars in this relatively nearby complex
will provide guidance in the interpretation of apparently supermassive stars
in distant locations. The search for companions will also be important for
verification of fundamental parameters derived from spectroscopy,
adjustments to main sequence fitting and distance estimations, determining
third light contributions of eclipsing binaries, identifying wide colliding
wind binaries, studying the relationship between orbital and spin angular
momentum, and discovering binaries amenable to future mass determinations.
The massive star environment in Cyg OB2 may be similar to the kinds found in
the earliest epoch of star formation, so that a study of the role of
binaries in Cyg OB2 will help us understand the formation processes of the
first stars in the Universe.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10778 - GSAcq (1,2,1) failed to RGA Hold (Gyro Control)

At AOS (103/22:48:00) GSAcq (1,2,1) scheduled at 103/22:21:38-22:28:56 had
failed to RGA hold (Gyro Control) due to QSTOP flag on FGS2.

OBAD MAP RSS: 5.31 a-s

COMPLETED OPS REQUEST:

18033-1 - LGA Support for TCS Engineering Data

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL

FGS GSacq 23 22
FGS REacq 17 17
OBAD with Maneuver 80 80

SIGNIFICANT EVENTS: (None)