Estimating coronal parameters using MoCA

The primary emission in Actve Galactic Nuclei (AGN) is widely believed to be due to Comptonisation of the thermal radiation from the accretion disk in a "corona" of hot electrons. The resulting spectra can, in the first approximation, be modelled with a cutoff power law. Taking advantage of MoCA, a Monte Carlo code calculating spectral and polarization properties of the coronal emission, we computed Comptonization spectra for different parameters of the hot corona, comparing them with cutoff power laws. Plots to convert phenomenological parameters (cutoff energy and photon index) into physical ones (temperature and optical depth) will be presented and discussed.