Daily # 4143

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4143

PERIOD COVERED: UT June 26, 2006 (DOY 177)

OBSERVATIONS SCHEDULED

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.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration - CR Persistence Part 4

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.

NIC3 10899

Identifying z7 galaxies from J-dropouts

NICMOS Parallel Imaging campaigns covered enough sky {250 pointings}
with enough sensitivity in the 110W and 160W filters to identify 6
extremely red resolved sources which are prime candidates for J-band
dropouts. Their complete absence of detectable J band flux can be
caused by an opaque Lyman cut-off at z=8-10. We propose to followup
these candidates with NICMOS imaging and jointly propose Spitzer IRAC
photometry. Deep F110W and Spitzer/IRAC 3.5/4.8 micron imaging will
confirm if any of these candidates are indeed Lyman Break galaxies
observed less than 500 Myrs after the Big Bang. Genuine LBGs will
remain undetected in F110W, while being detected with flat spectra in
the IRAC bands. The combined SED will provide information about the
stellar mass of these galaxies, and the possible presence of evolved
stars or dust reddening. The proposed observations will be sensitive
enough to detect the F110W flux from galaxies as red as {J-H}=2.8 {AB
mags, 5 sigma}. If any of the candidates are detected with bluer
colors, they will most likely be exceptional "Distant Red Galaxies" at
z of 4 to 6. The proposed data will constrain the stellar populations
of these extraordinarily red galaxies, which would be candidates for
the earliest, most massive galaxies which formed.

WFPC2 10132

UV Confirmation of New Quasar Sightlines Suitable for the Study of
Intergalactic Helium

The reionization of intergalactic helium is thought to have occurred
between redshifts of about 3 and 4. The study of HeII Lyman-alpha
absorption towards a half-dozen quasars at 2.7z3.5 demonstrates the
great potential of such probes of the IGM, but the current
critically-small sample limits confidence in resulting cosmological
inferences. The requisite unobscured quasar sightlines to
high-redshift are extremely rare, especially due to severe absorption
in random intervening Lyman-limit systems, but SDSS provides hundreds
of bright, new quasars at such redshifts potentially suitable for HeII
studies. Our cycle 13 SNAP program proposes to verify the UV
detectability of 40 new, bright, z2.9 SDSS quasars, but with special
emphasis on extending helium studies to the highest redshift
sightlines. Our proposed approach has already proven successful, and
additional sightlines will enable follow-up spectal observations to
measure the spectrum and evolution of the ionizing background
radiation, the density of intergalactic baryons, and the epoch of
reionization of the IGM.

WFPC2 10744

WFPC2 Cycle 14 Decontaminations and Associated Observations

This proposal is for the WFPC2 decons. Also included are instrument
monitors tied to decons: photometric stability check, focus monitor,
pre- and post-decon internals {bias, intflats, kspots, & darks}, UV
throughput check, VISFLAT sweep, and internal UV flat check.

WFPC2 10925

Imaging the Nearest Damped Lyman Alpha Absorbers

We propose to acquire broad-band and H-alpha imaging of three bright,
very nearby host galaxies for damped Ly-alpha absorbers {DLAs}. Our
targets are the only DLA hosts at z 0.03 {i.e., spatial resolutions
of 1.2 kpc}. The purpose of these observations is to discover the
detailed morphology and kinematics and thus the origins of the gas
giving rise to DLAs. While ground-based spectroscopy of DLAs is used
to infer indirectly the evolution of galaxy metallicity and thick disk
kinematics out to z 4, only with HST imaging of the very lowest
redshift DLA galaxies can we discover these relationships directly. In
conjunction with H I 21-cm VLA emission maps, broad-band and H-alpha
images of these DLAs will allow us to determine: {1} the sites of
active star formation in the host galaxies and their relationship to
the QSO sightline, {2} the presence of stellar streams, supernova
shells, or bipolar "superwind" outflows in DLA host galaxies, and {3}
the detailed spiral structure of the host galaxies, which will allow
us to use the lower resolution H I 21-cm emission line images to
determine unambiguous DLA kinematics with respect to the host galaxy
{i.e., is the DLA rotating with the disk?}. Thus, the high resolution
imaging will allow us to correctly interpret the kinematics and
metallicity information provided by the H I 21-cm VLA maps and HST UV
spectroscopy to better inform the high-z results.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10322 - FHST OBAD Failure @ 178/04:47:33z

FHST OBAD2 using trackers 1 and 3 (with maneuver) scheduled at
178/04:47:33 failed due to too many angle checks. OBAD2 had (RSS)
value of 112565.34 arcseconds. Pre-acquisition OBAD1 was successful
with (RSS) value of 1656.21 arcseconds.

10323 - REacq(1,2,1) failed to RGA Control @ 178/04:57:36z

The Target REacq(1,2,1) scheduled at 178/04:57:36 - 05:05:31 failed to
RGA Hold due to search radius limit exceeded on FGS-1. One 486 ESB
"a05" (FGS Coarse Track failed-Search Radius Limit Exceeded) was
received at 178/05:03:37. Prior GSAacq using same star id was
successful. Pre-acquisition OBAD1 was successful, OBAD2 failed per
(HSTAR# 10322). Enough attitude error had been introduced that the
acquisition could not succeed.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 07 07
FGS REacq 07 06 Hstar # 10323
OBAD with Maneuver 27 26 Hstar # 10322

SIGNIFICANT EVENTS: (None)