The continuum emission typically observed in the X-ray spectra of active galactic nuclei (AGNs) is thought to arise from inverse-Compton scattering of blackbody photons from the accretion disk by mildly relativistic thermal electrons in a rarefied and relatively hotter corona. By fitting theoretical spectral models (e.g., Poutanen & Svensson 1996; Coppi 1999) to the observed shape of an AGN coronal continuum it is possible to constrain some of its physical parameters, such as the electron temperature and optical depth (e.g., Fabian et al. 2015; Middei et al. 2019)
