2012A&A...545A..90D

We attempt to determine the nature of the high energy emission of the radio galaxy 3C 111, by distinguishing between the effects of the thermal and non-thermal processes. We study the X-ray spectrum of 3C 111 between 0.4keV and 200keV, and its spectral energy distribution, using data from the Suzaku satellite combined with INTEGRAL, Swift/BAT data, and Fermi/LAT data. We then model the overall spectral energy distribution by including radio and infrared data. The combined Suzaku, Swift and INTEGRAL data are represented by an absorbed exponentially cut-off power-law with reflection from neutral material with a photon index Γ=1.68±0.03, a high-energy cut-off E_cut=227_–67⁺¹⁴³keV, a reflection component with R=0.7±0.3 and a Gaussian component to account for the iron emission-line at 6.4keV with an equivalent width of EW=85±11eV. The X-ray spectrum appears dominated by thermal, Seyfert-like processes, but there are also indications of non-thermal processes. The radio to γ-ray spectral energy distribution can be fit with a single-zone synchrotron-self Compton model, with no need for an additional thermal component. We suggest a hybrid scenario to explain the broad-band emission, including a thermal component (iron line, reflection) that dominates in the X-ray regime and a non-thermal one to explain the spectral energy distribution.