Status Report

NASA Hubble Space Telescope Daily Report #4431

By SpaceRef Editor
August 22, 2007
Filed under , ,
NASA Hubble Space Telescope Daily Report #4431

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.


– Continuing to collect World Class Science

PERIOD COVERED: UT August 21, 2007 (DOY 233)


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 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.

NIC3 11082

NICMOS Imaging of GOODS: Probing the Evolution of the Earliest Massive Galaxies, Galaxies Beyond Reionization, and the High Redshift Obscured Universe

Deep near-infrared imaging provides the only avenue towards understanding a host of astrophysical problems, including: finding galaxies and AGN at z > 7, the evolution of the most massive galaxies, the triggering of star formation in dusty galaxies, and revealing properties of obscured AGN. As such, we propose to observe 60 selected areas of the GOODS North and South fields with NICMOS Camera 3 in the F160W band pointed at known massive M > 10^11 M_0 galaxies at z > 2 discovered through deep Spitzer imaging. The depth we will reach {26.5 AB at 5 sigma} in H_160 allows us to study the internal properties of these galaxies, including their sizes and morphologies, and to understand how scaling relations such as the Kormendy relationship evolved. Although NIC3 is out of focus and undersampled, it is currently our best opportunity to study these galaxies, while also sampling enough area to perform a general NIR survey 1/3 the size of an ACS GOODS field. These data will be a significant resource, invaluable for many other science goals, including discovering high redshift galaxies at z > 7, the evolution of galaxies onto the Hubble sequence, as well as examining obscured AGN and dusty star formation at z > 1.5. The GOODS fields are the natural location for HST to perform a deep NICMOS imaging program, as extensive data from space and ground based observatories such as Chandra, GALEX, Spitzer, NOAO, Keck, Subaru, VLT, JCMT, and the VLA are currently available for these regions. Deep high-resolution near-infrared observations are the one missing ingredient to this survey, filling in an important gap to create the deepest, largest, and most uniform data set for studying the faint and distant universe. The importance of these images will increase with time as new facilities come on line, most notably WFC3 and ALMA, and for the planning of future JWST observations.

WFPC2 10901

UV-Luminous Globular Clusters in NGC 1399

Ultraviolet observations have revealed remarkable diversity among old stellar populations in globular clusters and E/S0 galaxies. We recently discovered with HST/STIS that globular clusters in the giant elliptical galaxy M87 have the most heavily populated hot horizontal branches of any stellar systems yet studied. Their far-UV/optical colors are up to 1 mag bluer than any Milky Way globular cluster and approach the theoretical limits for production of hot-HB stars in old stellar populations. The differences among the metal-poor clusters are particularly interesting, because it is thought that these objects reflect the earliest stages of galaxy formation at high redshifts. Here we propose deep ACS far-UV imaging of a second gE galaxy, NGC 1399, with a cluster system that is well-studied at longer wavelengths, to determine whether it shares characteristics with M87. These observations bear on aspects of advanced stellar evolution, on the histories of globular clusters in different environments, and on the interpretation of the “ultraviolet upturn” phenomenon in elliptical galaxies and its value as a population probe in distant galaxies.

WFPC2 11031

CTE Background Dependence Closeout

Measuring the charge transfer efficiency {CTE} of an astronomical CCD camera is crucial to determining the CCD’s photometric fidelity across the field of view. WFPC2’s CTE has degraded steadily over the last 13 years because of continuous exposure to trapped particles in HST’s radiation environment. The fraction of photometric signal lost from WFPC2’s CTI {charge transfer inefficiency} is a function of WFPC2’s time in orbit, the integrated signal in the image, the location of the image on the CCD, and the background signal. Routine monitoring of WFPC2’s CTE over the last 13 years permits an assessment of all but the last condition. The dependence of CTE on background signal must be characterized, however, because a large fraction of WFPC2 images have been obtained under conditions of significant sky background. This program aims to assess the end-of-life CTE of WFPC2’s CCDs separately as a function of background signal. Traditional images of an off-center field in NGC 5139 {Omega Cen} are recorded after preflashing {or before postflashing} the CCDs with internal lamps to provide average background signals of 0-160 e-, which span the range of sky backgrounds observed in ~99% of long-exposure narrow- and broad-band WFPC2 images.


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

HSTARS: (None)



                       SCHEDULED      SUCCESSFUL 
FGS GSacq               06                06 
FGS REacq               08                08 
OBAD with Maneuver      28                28 


SpaceRef staff editor.