<i>ASCA</i>Observations of Seyfert 1 Galaxies. II. Relativistic Iron Kα Emission

Abstract

We present evidence for widespread relativistic e ects in the central regions of active galactic nuclei. In a sample of 18 Seyfert 1 galaxies observed by ASCA, 14 show an iron Ka line that is resolved, with mean width keV for a Gaussian prole (full width at half-maximum, FWHM D 50,000 p Ka \ 0.43 ^0.12 km s~1). However, many of the line proles are asymmetric. A strong red wing is indicative of gravitational redshifts close to a central black hole, and accretion disk models provide an excellent description of the data.