Daily # 4209

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4209

PERIOD COVERED: UT September 28, 2006 (DOY 271)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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 10894

Probing the Birth of Super Star Clusters with NICMOS

The formation of ``super star clusters" represents an extreme mode of
star formation in the local universe. Star clusters with radii 5pc
and masses exceeding 10^4 solar masses are now known to be common in
starbursts. These clusters are amazingly densely packed with massive
stars, and can have a violent impact on their host galaxies and the
surrounding IGM. The effects of massive star clusters perhaps were
even more important in the earlier universe, when galaxy mergers and
starbursts were common, and the formation of massive globular clusters
was ubiquitous. However, our knowledge of the formation and early
evolution of such massive clusters remains poorly understood, and
observations have only begun to probe these stages. The near-IR fluxes
and colors of natal clusters change dramatically in their early stages
of evolution, providing important diagnostics. We will use NICMOS to
explore the early evolution of massive star clusters through
observations of a sample of nearby starburst galaxies containing the
recently discovered ultra-young massive star clusters. First
identified as compact optically- thick free-free radio sources, these
natal clusters are still embedded in their birth material and obscured
at optical wavelengths. Sensitive, high-resolution observations in the
near-IR are critical for investigating the properties of these
clusters as they evolve from being completely obscured by their natal
clouds to fully emerged and optically visible. NICMOS F160W, F205W,
F187N, and F190N {roughly H, K, and Pa-alpha} images will allow us to
determine their ages, extinctions, ionizing fluxes, embedded stellar
masses, and the morphological relationship between radio, mid-IR, and
optically visible clusters. These results will ultimately provide
insight into the earliest stages of super star cluster evolution and
the properties of massive star formation throughout the universe.

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.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST:
17935-0 - SA Section 1 and 5 Current Anomaly Investigation

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 03 03
FGS REacq 08 08
OBAD with Maneuver 22 22


SIGNIFICANT EVENTS:

SA Section Anomaly Investigation Flash Report #2

On DOY 2006/271, the commanding for the SA Sections 1 and 5 Current
Anomaly Investigation continued at 13:16 GMT with the opening of the
-CC SPA trim relay on SA section 1. A distinct fault current behavior
was observed - SA section 1 current read ~2.6A higher than nominal
values for removing one 4-string SPA which is concurrent with the
existing -CC SPA short to structure.

In the subsequent test orbit, the +D SPA trim relay on SA section 1
was opened yielding a nominal output for removing a 5-string SPA. For
both test orbits, a step decrease in SA section 1 current did not
occur simultaneously with off-lining either SPA. Instead there was a
~1A step decrease in SA section 1 current when battery 5 reached
charge cut-off later in the orbit (similar to fault behavior in most
orbits since the initial event on DOY 2006/222).

In all orbits, SA section 5 current has continued to read ~1.8A higher
than nominal when battery 5 reached charge cut-off.

The test completed on DOY 2006/271 at 16:05 GMT. EPS SEs will provide
a more detailed analysis of the test results in the near future.