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NASA Hubble Space Telescope Daily Report #4208

Status Report From: Space Telescope Science Institute
Posted: Thursday, September 28, 2006

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HUBBLE SPACE TELESCOPE DAILY REPORT # 4208

- Continuing to collect World Class Science

PERIOD COVERED: UT September 27, 2006 (DOY 270)

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.

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.

NIC3 10780

The Unusual Afterglow and Host Galaxy of the Short GRB 060121

We request Director's Discretionary Time to observe the afterglow and host galaxy of the short- hard gamma-ray bursts GRB 060121. This is only the fourth time an optical afterglow of a short- hard burst has been found at its properties are significantly different to other cases. Both the afterglow and host galaxy are much fainter than previous short bursts {for which optical afterglows have been located} and the afterglow may also show the signature of dust extinction. Such extinction is completely unexpected for short bursts, given the currently popular model of their origin in NS-NS mergers. We propose ACS and NICMOS observations which will locate the afterglow and host galaxy of GRB 060121, provide constraints on its beaming angle, search for the signature of dust, and measure the offset from its host. These observations offer a strong test of NS-NS merger models.

NIC3 10899

Identifying z>7 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:

10450 - GSacq(2,1,2) failed

GSacq(2,1,2) scheduled at 270/17:09:05 failed to RGA control with QF2STOPF and QSTOP flags set at 17:14:24. No other flag were seen. OBAD1 showed errors of V1= -1081.30, V2= 905.51, V3= -2395.45, RSS= 2779.48. OBAD2 showed errors of V1= 9.75, V2= -1.79, V3= 9.77, RSS= 13.92.

COMPLETED OPS REQUEST:

COMPLETED OPS NOTES: (None)

                         SCHEDULED      SUCCESSFUL
FGS GSacq               04                    03
FGS REacq               06                    06
OBAD with Maneuver  20                    20

SIGNIFICANT EVENTS:

SA Section Anomaly Investigation Flash Report #1

On DOY 2006/270, the commanding for the SA Sections 1 and 5 Current Anomaly Investigation commenced at 13:16 GMT with the opening of the +E SPA trim relay on SA section 5. A distinct fault current behavior was observed - SA section 1 current experienced a step decrease of ~1.4A concurrent with opening the +E SPA trim relay.

In two subsequent test orbits, the step decrease in SA section 1 current did not occur simultaneously with off-lining the -A (SA section 5) and +DD (SA section 1) SPAs. 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 investigation will continue with the commanding of the last two remaining SPA trim relays, -CC and +D, on DOY 2006/271 at 13:15 GMT (Thursday, September 28th at 9:15 am local). An additional flash report will be provided at the completion of the test.

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