Status Report

NASA Hubble Space Telescope Daily Report #4427

By SpaceRef Editor
August 16, 2007
Filed under , ,
NASA Hubble Space Telescope Daily Report #4427
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Notice: Due to the conversion of some ACS WFC or HRC observations into WFPC2, or NICMOS observations after the loss of ACS CCD science capability in January, there may be an occasional discrepancy between a proposal’s listed (and correct) instrument usage and the abstract that follows it.

HUBBLE SPACE TELESCOPE DAILY REPORT #4427

– Continuing to collect World Class Science

PERIOD COVERED: UT August 15, 2007 (DOY 227)

OBSERVATIONS SCHEDULED

ACS/SBC 10840

The FUV fluxes of Tauri stars in the Taurus molecular cloud Present and forthcoming ground-based and space surveys of the T Tauri stars in the Taurus molecular cloud will provide information from high energy stellar and accretion radiation to low energy solid state and molecular emission from the disk, making those stars perfect laboratories to carry out self-consistent studies of disk physics and evolution. We propose to complete this wealth of information by obtaining ACS/FUV spectra for a significant sample of Taurus T Tauri stars, covering a range of accretion properties and dust evolutionary stages. FUV fluxes carry ~ 10 – 100 more energy than X-rays into these disks and are thus crucial gas heating agents and key to disk dispersal by photoevaporation. These observations are a pre-requisite to interpret observations with Spitzer, SOFIA, Herschel, and ALMA, and will become one of the important legacies of HST to the star formation community.

NIC1 11063

NICMOS Focus Monitoring

This program is a version of the standard focus sweep used since cycle 7. It has been modified to go deeper and uses more narrow filters for improved focus determination. For Cycle14 a new source has been added in order to accommodate 2-gyro mode: the open cluster NGC1850. The old target, the open cluster NGC3603, will be used whenever available and the new target used to fill the periods when NGC3603 is not visible. Steps: a} Use refined target field positions as determined from cycle 7 calibrations b} Use MULTIACCUM sequences of sufficient dynamic range to account for defocus c} Do a 17- point focus sweep, +/- 8mm about the PAM mechanical zeropoint for each cameras 1 and 2, in 1.0mm steps. d} Use PAM X/Y tilt and OTA offset slew compensations refined from previous focus monitoring/optical alignment activities.

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 DARKs. 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 11133

Late-Time Photometry of SN 2005hk: A New Kind of Type Ia Supernova

Our lack of understanding of Type Ia supernova {SN Ia} explosions limits our confidence in their use for cosmology. While there is broad agreement that these objects represent the explosions of white dwarfs, the details of the explosion mechanism are not well- understood. Recent observations have detected a previously unacknowledged variant class of SNe Ia whose photometric and spectroscopic peculiarities make them quite distinct from normal SNe Ia. These objects represent a challenge for thermonuclear supernova models, as a complete theory of exploding white dwarfs must allow for their existence. A particularly well-studied example of this class of objects is the recent SN 2005hk, whose properties in some respects resemble those of models which invoke a subsonic burning front, called a deflagration. We propose to test SN Ia models by obtaining late-time photometry for this extreme SN Ia using WFPC2 and NICMOS on HST. We will accurately measure the late-time photometric decline rate and spectral energy distribution {SED}. These observations will allow us to test whether the ejecta contain the large amount of oxygen predicted by certain models, the efficiency of energy deposition by gamma rays and positrons, and possibly detect major evolution of the SED expected due to a change in the dominant cooling mechanism of the ejecta.

NIC2 11219

Active Galactic Nuclei in nearby galaxies: a new view of the origin of the radio-loud radio- quiet dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type galaxies {drawn from a complete radio selected sample} we have found evidence that the radio-loud/radio-quiet dichotomy is directly connected to the structure of the inner regions of their host galaxies in the following sense: [1] Radio-loud AGN are associated with galaxies with shallow cores in their light profiles [2] Radio-quiet AGN are only hosted by galaxies with steep cusps. Since the brightness profile is determined by the galaxy’s evolution, through its merger history, our results suggest that the same process sets the AGN flavour. This provides us with a novel tool to explore the co-evolution of galaxies and supermassive black holes, and it opens a new path to understand the origin of the radio-loud/radio-quiet AGN dichotomy. Currently our analysis is statistically incomplete as the brightness profile is not available for 82 of the 116 targets. Most galaxies were not observed with HST, while in some cases the study is obstructed by the presence of dust features. We here propose to perform an infrared NICMOS snapshot survey of these 82 galaxies. This will enable us to i} test the reality of the dichotomic behaviour in a substantially larger sample; ii} extend the comparison between radio-loud and radio-quiet AGN to a larger range of luminosities.

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: (None)

COMPLETED OPS NOTES: (None)

                         SCHEDULED      SUCCESSFUL 
FGS GSacq                10                  10 
FGS REacq                04                  04 
OBAD with Maneuver       28                  28 

SIGNIFICANT EVENTS:  (None)

SpaceRef staff editor.