ROSAT, ASCA, and OSSE observations of the broad-line radio galaxy 3C 120

We present simultaneous observations of the superluminal radio galaxy 3C 120 performed with the ASCA and GRO (OSSE) satellites in 1994 February-March, as well as an analysis of all the ROSAT archival data. The ASCA spectrum of this object can be described by an absorbed (N-H = 1.6 x 10(21) cm(-2)) power law with a photon index of T-ASCA = 2 and a very broad (sigma > 0.8 keV) intense iron line (EW > 400 eV) at similar to 6 keV. The combined ASCA-OSSE data do not exclude the presence of a narrower (sigma = 0.4 keV) and less intense (EW < 300 eV) iron line plus a hard component, corresponding either to reflection from an accretion disk or to a flatter power law from a jet. However, a single power law plus broad Fe line is preferred from a statistical point of view by the ASCA data. The ROSAT data yield a column density in excess of the Galactic value. The spectral slopes, ranging from Gamma(ROSAT) = 2.5 to 3.3, are steeper than that measured by ASCA, suggesting the presence of a soft excess. The 0.1-2 keV power-law slope is variable and softer at higher intensity. These results show that the combined soft and hard X-ray spectrum of 3C 120 is rather complex. The intrinsic absorption, the soft excess, and the iron line indicate that the X-ray emission from this blazar-like radio galaxy is dominated by a Seyfert-like component, at least in the 0.1-10 keV energy band. The jet contribution, if present, becomes important only at higher energies.