Diagnostics of Plasma Properties in Broad Line Region of AGNs

Abstract

The Boltzmann-plot (BPT) method for laboratory plasma diagnostic was used for a quick estimate of physical conditions in the Broad Line Region (BLR) of 14 Active Galactic Nuclei (AGNs). For the BLR of nine AGNs, where PLTE exist, the estimated electron temperature are in the range T $\sim$ 130000K - 37000K are in good agreement with previous estimates. The estimated electron densities depend on the opacity of the emitting plasma in the BLR, and they are in range from $10^9\rm cm^{-3}$ (for optically thick plasma) to $10^{14}\rm cm^{-3}$ (for optically thin plasma). Although an alternative of PLTE in some AGNs may be very high intrinsic reddening effect, this method may be used for fast insight into physical processes in the BLR prior to applying more sophisticated physical models.