Daily #4142

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4142

PERIOD COVERED: UT June 23,24,25, 2006 (DOY 174,175,176)

OBSERVATIONS SCHEDULED

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.

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.

NIC3 10632

Searching for galaxies at z6.5 in the Hubble Ultra Deep Field

We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the
area of the original Hubble Ultra Deep Field NICMOS parallel fields
and - through simultaneous parallel observations - deep NICMOS {F110W,
F160W} imaging of the ACS UDF area. Matching the extreme imaging depth
in the optical and near-IR bands will result in seven fields with
sufficiently sensitive multiband data to detect the expected typical
galaxies at z=7 and 8. Presently no such a field exist. Our combined
optical and near-IR ultradeep fields will be in three areas separated
by about 20 comoving Mpc at z=7. This will allow us to give a first
assessment of the degree of cosmic variance. If reionization is a
process extending over a large redshift interval and the luminosity
function doesn't evolve strongly beyond z=6, these data will allow us
to identify of the order of a dozen galaxies at 6.5z8.5 - using the
Lyman break technique - and to place a first constrain on the
luminosity function at z6.5. Conversely, finding fewer objects would
be an indication that the bulk of reionization is done by galaxies at
z=6. By spending 204 orbits of prime HST time we will capitalize on
the investment of 544 prime orbits already made on the Hubble Ultra
Deep Field {UDF}. We have verified that the program as proposed is
schedulable and that it will remain so even if forced to execute in
the 2-gyro mode. The data will be non-proprietary and the reduced
images will be made public within 2 months from the completion of the
observations.

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.

NIC2 10527

Imaging Scattered Light from Debris Disks Discovered by the Spitzer
Space Telescope Around 20 Sun-like Stars

We propose to use the high contrast capability of the NICMOS
coronagraph to image a sample of newly discovered circumstellar disks
associated with sun-like stars. These systems were identified by their
strong thermal infrared emission with the Spitzer Space Telescope as
part of the Spitzer Legacy Science program titled, "The Formation and
Evolution of Planetary Systems {FEPS}." Modelling of the thermal
excess emission in the form of spectral energy distributions alone
cannot distinguish between narrowly confined high opacity disks and
broadly distributed, low opacity disks. However, our proposed NICMOS
observations can, by imaging the light scattered from this material.
Even non- detections will place severe constraints on the disk
geometry, ruling out models with high optical depth. Unlike previous
disk imaging programs, our program contains a well defined sample of
solar mass stars covering a range of ages from ~10Myrs to a few Gyrs,
allowing us to study the evolution of disks from primordial to debris
for the first time. These results will greatly improve our
understanding of debris disks around Sun- like stars at stellar ages
nearly 10x older than any previous investigation. Thus we will have
fit a crucial piece into the puzzle concerning the formation and
evolution of our own solar system.

NIC1 10143

Ultracool companions to the nearest L dwarfs

We propose to conduct the most sensitive survey to date for low mass
companions to nearby L dwarfs. We will use NICMOS to image targets
drawn from a volume-complete sample of 70 L dwarfs within 20 parsecs.
The combination of infrared imaging and proximity will allow us to
search for T dwarf companions at separations as small as 1.6 AU. This
is crucial, since no ultracool binaries are currently known with
separations exceeding 15 AU. Only 10 dwarfs in this sample have
previous HST observations primarily at optical wavelengths. With the
increased sensitivity of our survey, we will provide the most
stringent test to date of brown dwarf models which envisage formation
as ejected stellar embryos. In addition, our observations will be
capable of detecting binaries with mass ratios as low as 0.3, and will
therefore also test the apparent preference for equal-mass ultracool
binaries. Finally, our observations offer the best prospect to date of
detecting companions significantly cooler than the coolest t dwarf
currently known.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10320 - GSacq(2,1,2) failed to RGA control @ 175/14:05:46z

During LOS GSacq(2,1,2) scheduled at 175/14:05:46 failed to RGA
control. At AOS only stop flags QF2STOPF and QSTOP where flagging.

10321 - GSacq(1,2,1) failed to RGA control @ 175/20:50:33z

GSacq(1,2,1) scheduled at 175/20:50:33 failed to RGA control due to
stop flag on FGS 2. At AOS(20:55:04) only stop flags QF2STOPF and
QSTOP where flagging. The OBAD2 at 20:45:25 showed erros of V1=9.81,
V2=3.62, V3=11.69, RSS=15.69. The Map at 20:57:49 showed erros of
V1=-6.80, V2=-2.47, V3=5.04,RSS=8.82.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES:
1341-3 - NCC TEST message use, reference HSTAR #9828 @ 174/18:08z
1386-4 - User Class for Quick Updated Proc's (CCS-H) @ 175/04:29z
1409-0 - Mnemonic Display Utility Work Around (CCS-H) @ 175/04:29z


SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 31 29 Hstar#
10320 & 10321
FGS REacq 08 08
OBAD with Maneuver 77 77

SIGNIFICANT EVENTS: (None)