Reprocessing and variable cold absorption in the broad-line radio galaxy 3C 390.3

A BeppoSAX observation of the Broad Line Radio-Galaxy 3C 390.3 is reported. For the first time, both the K-alpha iron line and a strong reflection hum p, produced by the illumination of the primary X-ray emission on cold matte r, are detected in this source. The 0.1-100 keV continuum is modeled by an absorbed hard power law (Gamma similar to 1.8) reflected at high energies b y material with a fairly large covering factor (Omega/2 pi similar or equal to 1). The iron line is centered at similar or equal to 6.4 keV (rest fram e), is intrinsically narrow (sigma = 73+/-(207)(73) eV), and has an equival ent width of similar or equal to 140 eV. We discuss the results in the context of current models for AGNs and sugges t that the primary X-ray power law continuum is probably produced by a hot inner flow, while the reprocessed radiation comes from an outer cold thin d isk, and/or from a thick torus at even larger radii. Further observations w ith BeppoSAX could distinguish between the latter two cases. Beamed radiati on associated to the radio jet is unlikely to contribute significantly to t he X-ray emission. Finally an historical study of the column density NH, also reported here, s hows that the absorption along the Line of sight changes in time. The N-H t ime variability, which is not correlated with that of the primary continuum , seems to imply variations of the geometry of the absorber rather than Var iations in the ionization state of the gas.