Physical properties of the BLR of AGN: Boltzmann-plot vs. CLOUDY models

Abstract

There are different spectroscopic methods for direct diagnostics of emitting plasma in astrophysical objects, but these methods could not be used in the case of the Broad Line Region (BLR) of Active Galactic Nuclei (AGN). Here we combine the Boltzmann-plot (BP) method [1], [2] and calculations performed with the photoionization code CLOUDY [3] in order to find a simple tool that would only use the observed broad Balmer and helium lines (HeII λ4686 and HeI λ5876) for the temperature diagnostics of the BLR. © 2007 American Institute of Physics.