Status Report

NASA Hubble Space Telescope Daily Report #4329

By SpaceRef Editor
March 29, 2007
Filed under , ,
NASA Hubble Space Telescope Daily Report #4329

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.


– Continuing to collect World Class Science

PERIOD COVERED: UT March 28, 2007 (DOY 087)


ACS/SBC 11011

Dissecting An Accretion Disk

We will use 5 epochs of CXO and HST imaging to determine the X-ray and UV size of the accretion disk of the lensed quasar RXJ1131–1231 using microlensing. Based on preliminary data, we find that the X-ray source is roughly 1/10 the size of the accretion disk in the rest-frame B-band. The new observations will significantly reduce the uncertainties in this estimate, provide a comparison between the size of the X-ray source and the size of the accretion disk in the rest frame ultraviolet, and have the signal-to-noise ratio necessary to begin examining the size of the hard and soft-band X-ray emission regions separately. The results will quantitatively test accretion disk theory and X-ray emission mechanisms.

NIC2 10858

NICMOS Imaging of the z ~ 2 Spitzer Spectroscopic Sample of Ultraluminous Infrared Galaxies

We propose to obtain NICMOS images of the first large sample of high-z ultra-luminous infrared galaxies {ULIRGs} whose redshifts and physical states have been determined with Spitzer mid-IR spectra. The detection of strong silicate absorption and/or PAH emission lines suggest that the these sources are a mixture of highly obscured starbursts, AGNs and composite systems at z=2. Although some of the spectra show PAH emission similar to local starburst ULIRGs, their bolometric luminosities are roughly an order of magnitude higher. One important question is if major mergers, which are the trigger for 95% of local ULIRGs, also drive this enormous energy output observed in our z=2 sample. The NICMOS images will allow us to {1} measure surface brightness profiles of z~2 ULIRGs and establish if major mergers could be common among our luminous sources at these early epochs, {2} determine if starbursts and AGNs classified based on their mid-IR spetra would have different morphological signatures, thus different dynamic state; {3} make comparisons with the similar studies of ULIRGs at z ~ 0 – 1, thus infer any evolutionary connections between high-z ULIRGs and the formation of normal, massive galaxies and quasars observed today.

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 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 images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC3 11080

Exploring the Scaling Laws of Star Formation

As a variety of surveys of the local and distant Universe are approaching a full census of galaxy populations, our attention needs to turn towards understanding and quantifying the physical mechanisms that trigger and regulate the large-scale star formation rates {SFRs} in galaxies.


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


10758 – GSAcq (2,3,3) failed due to STOP flag on FGS 2

GSAcq (2,3,3) scheduled from 087/21:24:29-21:31:50 failed due to STOP flags “QF2STOPF & QSTOP”.

OBAD #1 RSS: 1232.49 a-s

OBAD #2 RSS: 6.50 a-s

OBAD MAP RSS: 284.51 a-s



                      SCHEDULED      SUCCESSFUL 
FGS GSacq               09                 08 
FGS REacq               02                 02 
OBAD with Maneuver      22                 22 


SpaceRef staff editor.