Reprocessing of X-rays in AGN. I. Plane parallel geometry -- test of   pressure equilibrium
  We present a model of the vertical stratification and the spectra of an irradiated medium under the assumption of constant pressure. Such a solution has properties intermediate between constant density models and hydrostatic equilibrium models, and it may represent a flattened configuration of gas clumps accreting onto the central black hole. Such a medium develops a hot skin, thicker than hydrostatic models, but thinner than constant density models, under comparable irradiation. The range of theoretical values of the alpha_ox index is comparable to those from hydrostatic models and both are close to the observed values for Seyfert galaxies but lower than in quasars. The amount of X-ray Compton reflection is consistent with the observed range. The characteristic property of the model is a frequently multicomponent iron K alpha line. 
A.-M. Dumont (1), B. Czerny (2), S. Collin (1), P.T. Zycki (2) ((1)   Observatoire de Paris-Meudon, (2) Copernicus Astronomi...