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\nSeyfert galaxy NGC 1365, based on a 60 ks XMM-Newton observation performed in\nJanuary 2004. The two main results are: 1) We detect an obscuring cloud with\nN_H~3.5x10^23 cm^(-2) crossing the line of sight in ~25 ks. This implies a\ndimension of the X-ray source not larger than a few 10^13 cm and a distance of\nthe obscuring cloud of the order of 10^16 cm. Adopting the black hole mass\nM(BH) estimated from the M(BH)-velocity dispersion relation, the source size is\nD_S<20 R_G and the distance and density of the obscuring clouds are\nR~3000-10000 R_G and n~10^(10) cm^(-3), i.e. typical values for broad line\nregion clouds. 2) An iron emission line with a relativistic profile is detected\nwith high statistical significance. A time integrated fit of the line+continuum\nreflection components suggests a high iron abundance (~3 times solar) and an\norigin of these components in the inner part (~10 R_G) of the accretion disk,\nin agreement with the small source size inferred from the analysis of the\nabsorption variability.\n