Soft X-ray Variability and the Covering Fraction of Active Galactic Nuclei
1989 ◽
Vol 134
◽
pp. 118-119
The variability of soft X-rays (0.2 – 2 keV) in some low-luminosity type 1 Seyferts may partly be due to an extrinsic mechanism: dense clouds of gas in the broad-line region, opaque to soft X-rays, move across our line of sight to the X-ray emitting portions of the accretion disk (Reichert, Mushotzky, and Holt 1986; Lawrence and Elvis 1982; Halpern 1984). As the clouds move, the covering fraction changes stochastically. Evidence for partial covering of the X-ray source in low-luminosity AGNs has been seen in soft X-ray spectra by Holt et al. (1980) and Reichert et al. (1985).
1997 ◽
Vol 112
(2)
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pp. 271-283
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Keyword(s):
2013 ◽
Vol 438
(1)
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pp. 604-619
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Keyword(s):
1987 ◽
Vol 121
◽
pp. 161-167
2014 ◽
Vol 793
(2)
◽
pp. 100
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Keyword(s):