Status Report

NASA Hubble Space Telescope Daily Report #4917

By SpaceRef Editor
August 25, 2009
Filed under , ,


PERIOD COVERED: 5am August 25 – 5am August 26, 2009 (DOY 237/09:00z-238/09:00z)


ACS/WFC3 11013

Continued M31 Monitoring for Black Hole X-ray Nova

We have been caring out a Chandra (GO+GTO) and HST (GO) program to find Black Hole X-ray Nova (BHXN) and their optical counterparts in M31 for several years. To date we have found >2 dozen BHXN and 3 HST optical counterparts for these BHXN. Our results suggest a rather high ratio of BH to neutron star (NS) binaries, or a high duty cycle for the BHXN. We propose to continue this program, with the goal of determining the orbital period distribution and duty cycles of these BHXN. Current results yield 3 orbital periods and 3 upper limits. Our proposed observations will ~double the total number of periods and therefore yield sufficient numbers to make a first approximation of the orbital period distribution. The orbital period distribution is the fundamental observable parameter any binary stellar evolution models must match, and the duty cycle is very poorly known but directly influences the binary lifetime. M31 is the only galaxy in which this extra-galactic study of BHXN is feasible. Furthermore, the 2 HST observations will allow us to estimate the orbital period of a single super-Eddington source.

COS 11484

COS FUV Optics Alignment and Focus

After FUV detector functionality has been confirmed in COS25 (program 11483) and the initial focus updates determined in COS08 and COS 09 (programs 11468 and 11469), a sequence of 13 FUV focus-sweep exposures of a sharp-lined external target will be made with each grating (4 orbits per grating) to perform a fine-focus sweep. After the data are analyzed, a patchable constant SMS update of OSM1 focus for each grating will be uplinked. A verification visit will be executed after the uplink. Observations require high S/N and should be taken in TIME-TAG (FLASH=YES) mode.

NIC2/WFC3/IR 11548

NICMOS Imaging of Protostars in the Orion A Cloud: The Role of Environment in Star Formation

We propose NICMOS observations of a sample of 252 protostars identified in the Orion A cloud with the Spitzer Space Telescope. These observations will image the scattered light escaping the protostellar envelopes, providing information on the shapes of outflow cavities, the inclinations of the protostars, and the overall morphologies of the envelopes. In addition, we ask for Spitzer time to obtain 55-95 micron spectra of 75 of the protostars. Combining these new data with existing 3.6 to 70 micron photometry and forthcoming 5-40 micron spectra measured with the Spitzer Space Telescope, we will determine the physical properties of the protostars such as envelope density, luminosity, infall rate, and outflow cavity opening angle. By examining how these properties vary with stellar density (i.e. clusters vs groups vs isolation) and the properties of the surrounding molecular cloud; we can directly measure how the surrounding environment influences protostellar evolution, and consequently, the formation of stars and planetary systems. Ultimately, this data will guide the development of a theory of protostellar evolution.

STIS/CCD 11844

CCD Dark Monitor Part 1

Monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns.

STIS20 11402

STIS-20 NUV MAMA Dark Monitor

The STIS NUV-MAMA dark current is dominated by a phosphorescent glow from the detector window. Meta-stable states in this window are populated by cosmic ray impacts, which, days later, can be thermally excited to an unstable state from which they decay, emitting a UV photon. The equilibrium population of these meta-stable states is larger at lower temperatures; so warming up the detector from its cold safing will lead to a large, but temporary, increase in the dark current.

To monitor the decay of this glow, and to determine the equilibrium dark current for Cycle 17, four 1380s NUV-MAMA ACCUM mode darks should be taken each week during the SMOV period. Once the observed dark current has reached an approximate equilibrium with the mean detector temperature, the frequency of this monitor can be reduced to one pair of darks per week.


Star Formation in Nearby Galaxies

Star formation is a fundamental astrophysical process; it controls phenomena ranging from the evolution of galaxies and nucleosynthesis to the origins of planetary systems and abodes for life. The WFC3, optimized at both UV and IR wavelengths and equipped with an extensive array of narrow-band filters, brings unique capabilities to this area of study. The WFC3 Scientific Oversight Committee (SOC) proposes an integrated program on star formation in the nearby universe which will fully exploit these new abilities. Our targets range from the well-resolved R136 in 30 Dor in the LMC (the nearest super star cluster) and M82 (the nearest starbursting galaxy) to about half a dozen other nearby galaxies that sample a wide range of star-formation rates and environments. Our program consists of broad band multiwavelength imaging over the entire range from the UV to the near-IR, aimed at studying the ages and metallicities of stellar populations, revealing young stars that are still hidden by dust at optical wavelengths, and showing the integrated properties of star clusters. Narrow-band imaging of the same environments will allow us to measure star-formation rates, gas pressure, chemical abundances, extinction, and shock morphologies. The primary scientific issues to be addressed are: (1) What triggers star formation? (2) How do the properties of star-forming regions vary among different types of galaxies and environments of different gas densities and compositions? (3) How do these different environments affect the history of star formation? (4) Is the stellar initial mass function universal or determined by local conditions?

WFC3/UVIS 11432

UVIS Internal Flats

This proposal will be used to assess the stability of the flat field structure for the UVIS detector. Flat fields will be obtained for all filters using the internal D2 and Tungsten lamps.

This proposal corresponds to Activity Description ID WF19. It should execute only after the following proposals have executed: WF08 – 11421 WF09 – 11422 WF11 – 11424 WF15 – 11428

WFC3/UVIS 11446

WFC3 UVIS Dark Current, Readnoise, and CTE

This proposal obtains full-frame, four-amp readout bias and dark frames at regularly- spaced intervals throughout SMOV in order to assess and monitor dark current, bad (warm, hot, dead) pixels, and readnoise. In addition, a set of internals using the WFC3 calsystem are taken to provide a baseline CTE measurement. WFC3-33

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K subarray biases are acquired at less frequent intervals throughout the cycle to support subarray science observations. The internals from this proposal, along with those from the anneal procedure (11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS).


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

HSTARS: (None)




FGS GSAcq 04 04
FGS REAcq 13 13
OBAD with Maneuver 03 03


SpaceRef staff editor.