Are the Nuclei of Seyfert 2 Galaxies Viewed Face-On?
Author(s) -
K. A. Weaver,
C. S. Reynolds
Publication year - 1998
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/311527
Subject(s) - physics , torus , astrophysics , galaxy , active galactic nucleus , accretion (finance) , superposition principle , line (geometry) , accretion disc , emission spectrum , astronomy , spectral line , nucleus , geometry , mathematics , quantum mechanics , biology , microbiology and biotechnology
We show from modeling the Fe Kalpha line in the ASCA spectra of four X-raybright narrow emission line galaxies (Seyfert types 1.9 and 2) that two equallyviable physical models can describe the observed line profile. The first isdiscussed by Turner et al. (1998) and consists of emission from a nearlypole-on accretion disk. The second, which is statistically preferred, is asuperposition of emission from an accretion disk viewed at an intermediateinclination of about 48 degrees and a distinct, unresolved feature thatpresumably originates some distance from the galaxy nucleus. The intermediateinclination is entirely consistent with unified schemes and our findingschallenge recent assertions that Seyfert 2 galaxies are preferentially viewedwith their inner regions face-on. We derive mean equivalent widths for thenarrow and disk lines of =60 eV and = 213 eV, respectively. TheX-ray data are well described by a geometry in which our view of the activenucleus intersects and is blocked by the outer edges of the obscuring torus,and therefore do not require severe misalignments between the accretion diskand the torus.Comment: 19 pages, 3 postscript figures. Accepted for publication in ApJ
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