Variable partial covering and a relativistic iron line in NGC 1365

Abstract

We present a complete analysis of the hard X-ray (2-10 keV) properties of the Seyfert galaxy NGC 1365, based on a 60 ks XMM-Newton observation performed in 2004 January. The two main results are as follows. (1) We detect an obscuring cloud with N-H similar to 3.5 x 10(23) cm(-2) crossing the line of sight in similar to 25 ks. This implies a dimension of the X-ray source not larger than a few 1013 cm and a distance of the obscuring cloud of the order of 1016 cm. Adopting the black hole mass M-BH estimated from the M-BH-velocity dispersion relation, the source size is D-S < 20R(G) and the distance and density of the obscuring clouds are R similar to 3000-10,000R(G) and n similar to 10(10) cm(-3), i.e., typical values for broad-line region clouds.(2) An iron emission line with a relativistic profile is detected with high statistical significance. A time-integrated fit of the line+continuum reflection components suggests a high iron abundance(approximately three times solar) and an origin of these components in the inner part (within similar to 10R(G)) of the accretion disk, in agreement with the small source size inferred from the analysis of the absorption variability.