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A statistical analysis of the broadband 0.1 to 3.5 keV spectral properties of X-ray-selected active galactic nucleiWe survey the broadband spectral properties of approximately 500 X-ray-selected active galactic nuclei (AGNs) observed with the Einstein Observatory. Included in this survey are the approximately 450 AGNs in the Extended Medium Sensitivity Survey (EMSS) of Gioia et al. (1990) and the approximately 50 AGNs in the Ultrasoft Survey of Cordova et al. (1992). We present a revised version of the latter sample, based on the post publication discovery of a software error in the Einstein Rev-1b processing. We find that the mean spectral index of the AGNs between 0.1 and 0.6 keV is softer, and the distribution of indices wider, than previous estimates based on analyses of the X-ray spectra of optically selected AGNs. A subset of these AGNs exhibit flux variabiulity, some on timescales as short as 0.05 days. A correlation between radio and hard X-ray luminosity is confirmed, but the data do not support a correlation between the radio and soft X-ray luminosities, or between radio loudness and soft X-ray spectral slope. Evidence for physically distinct soft and hard X-ray components is found, along with the possibility of a bias in previous optically selected samples toward selection of AGNs with flatter X-ray spectra.
Document ID
19950050290
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Thompson, R. J.
(Pennsylvania State Univ. University Park, PA, United States)
Cordova, F. A.
(Pennsylvania State Univ. University Park, PA, United States)
Date Acquired
August 16, 2013
Publication Date
October 10, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 434
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A81889
Funding Number(s)
CONTRACT_GRANT: NAG5-1899
CONTRACT_GRANT: NAG5-1763
Distribution Limits
Public
Copyright
Other

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