The Hybrid AGN Core of 3C 111

Sandra de Jong (François Arago Centre, APC, Université Paris Diderot)

To shed light on the physical processes that produce high-energy emission in the non-blazar radio galaxy 3C 111 we analyzed both the X-ray spectrum in between 0.4 and 200 keV and the broad-band spectral energy distribution of this source using archival and previously unpublished data from Suzaku, INTEGRAL, Swift and Fermi/LAT. 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 ? = 1.68±0.03, a high-energy cut-off Ecut = 227+143-67 keV, a reflection component with R = 0.7±0.3 and a Gaussian component to account for the iron emission line at 6.4 keV with an equivalent width of EW = 85±11 eV. The X-ray spectrum appears dominated by thermal, Seyfert-like processes, but we cannot exclude a non-thermal component. The radio to gamma-ray spectral energy distribution can be fit with a single-zone synchrotron- self Compton model, with no need for an additional thermal component. The broad-band emission is of non-thermal, blazar-like origin, whereas the X-ray spectrum shows both thermal components (reflection, iron line) and non-thermal components (the iron line is weak and variable). Furthermore the high-energy cut-off can be interpreted as either an exponential cut-off of the thermal spectrum or as a turn-over of the non-thermal spectrum. Therefore we suggest a hybrid model to explain the broad-band non-thermal emission and the thermal component in the X-ray spectrum.