NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-20 T10:17:32 PDT
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For refcode 1999ApJ...519..637M:
Retrieve 36 NED objects in this reference.
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NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
1999ApJ...519..637M BATSE Observations of the Piccinotti Sample of Active Galactic Nuclei A. MALIZIA Department of Physics and Astronomy, University of Southampton, SO17 1BJ, England L. BASSANI Istituto Technologie e Studio delle Radiazioni Extraterrestri/CNR, via Gobetti 101, 40129 Bologna, Italy S. N. ZHANG University Space Research Association, 4950 Corporate Drive, Suite 100, Huntsville, AL 35806 A. J. DEAN Department of Physics and Astronomy, University of Southampton, SO17 1BJ, England W. S. PACIESAS Department of Physics, University of Alabama, Huntsville, AL 35899 AND G. G. C. PALUMBO Astronomy Department, Universita di Bologna, Bologna, Italy Received 1998 November 30; accepted 1999 February 17 ABSTRACT BATSE Earth-occultation data have been used to search for emission in the 20-100 keV band from all sources in the Piccinotti sample, which represents the only complete 2-10 keV survey to date of the extragalactic sky down to a limiting flux of 3.1x10^11^ ergs cm^-2^ s^-1^. Nearly 4 yr of observations have been analyzed to reach a 5 {sigma} sensitivity level of about 7.8x10^-11^ ergs cm^-2^ s^-1^ in the band considered. Of the 36 sources in the sample, 14 have been detected above the 5 {sigma} confidence level, while marginal detection (3<={sigma}<=5) can be claimed for 13 sources; for nine objects 2 {sigma} upper limits are reported. A comparison of BATSE results with data at higher energies is used to estimate the robustness of our data analysis: while the detection level of each source is reliable, the flux measurement maybe overestimated in some sources by as much as 35%, probably because of incomplete data cleaning. Comparison of BATSE fluxes with X-ray fluxes obtained in the 2-10 keV range and averaged over years indicates that a canonical power law of photon index 1.7 gives a good description of the broadband spectra of bright active galactic nuclei (AGNs) and that spectral breaks preferentially occur above 100 keV. Subject headings: galaxies: active-gamma rays: observations -X-rays: galaxies
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