The ASCA X-ray spectrum of the powerful radio galaxy 3C 109

We report the results from an ASCA X-ray observation of the powerful broad-line radio galaxy 3C 109. The ASCA spectra confirm our earlier ROSAT detection of intrinsic X-ray absorption associated with the source. The absorbing material obscures a central engine of quasar-like luminosity. The luminosity is variable, having dropped by a factor of 2 since the ROSAT observations 4 years before. The ASCA data also provide evidence for a broad iron emission line from the source, with an intrinsic FWHM of similar to 120 000 km s(-1). Interpreting the line as fluorescent emission from the inner parts of an accretion disc, we can constrain the inclination of the disc to be > 35 degrees, and the inner radius of the disc to be <70 Schwarzschild radii. Our results support unified schemes for active galaxies, and demonstrate a remarkable similarity between the X-ray properties of this powerful radio source and those of lower luminosity, Seyfert 1 galaxies.