NASA/IPAC EXTRAGALACTIC DATABASE
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For refcode 1997AJ....113.2134O:
Retrieve 1326 NED objects in this reference.
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1997AJ....113.2134O A SURVEY OF THE EINSTEIN IPC DATABASE FOR EXTENDED X-RAY SOURCES B. R. OPPENHEIMER and D. J. HELFAND Department of Astronomy, Columbia University, 538 West 120th Street, New York, New York 10027, Electronic mail: bro@astro.caltech.edu, djh@carmen.phys.columbia.edu E. J. GAIDOS Center for Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge. Massachusetts 02139, Electronic mail: ejgaidos@space.mit.edu Received 1997 January 27; revised 1997 February 24 ABSTRACT We present the results of a new analysis of the entire set of data collected by the Imaging Proportional Counter (IPC) on board the Einstein Observatory. Our survey is distinct from previous work such as the Einstein Extended Medium Sensitivity Survey (EMSS) in that it is designed to find extended sources and diffuse emission rather than point sources. In addition, the source detection algorithm is substantially improved over that used for the EMSS. We have searched for sources using circular apertures with variable radii up to 6.10'. We have constructed criteria to ascertain which of the detections are truly diffuse and which of the sizes best approximates each detection. Using these criteria we have produced a catalog of 1326 extended source candidates at high Galactic latitude (|b| > 20 deg). Cross-correlating this list with existing source catalogs yields a reasonably comprehensive identification of the sources in our list. We find that over 400 are identified with known clusters of galaxies. Other objects are identified with galaxies, supernova remnants, AGN, and stars; the first two categories are often truly extended objects, while the latter two sets of objects can appear extended as a consequence of their soft X-ray spectra coupled with the broad point spread function of the IPC at low energies. A total of 321 extended sources remain unidentified. Many of these may be heretofore uncataloged clusters and groups of galaxies at moderate redshifts.
Retrieve 1326 NED objects in this reference.
Please click here for ADS abstract

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