Simulation of Fe II Emission Spectra in Active Galactic Nuclei*

Accurate radiative and collision atomic data for a large number of lines in a broad wavelength region from the infrared to ultraviolet has been used in numerical simulations of Fe II emission spectra of Broad Line Region of Active Galactic Nuclei. The analysis of Fe II emission spectra provides useful diagnostics of physical conditions and Fe abundance in the gas. We investigated Fe II emission spectra using self- consistent photoionization spectral synthesis code CLOUDY. Our numerical Fe II ion model includes lowest 340 fine-structure levels of the 3d⁶4s, 3d⁵4s², 3d⁷, and 3d⁶4p configurations plus some lowest levels of the 3d⁵4s4p configuration and predicts 57630 Fe II emission lines. Our model incorporates experimental energy levels and transition probabilities where available and updated reliable radiative and collision rates from our recent calculations. We have studied variation of Fe II emission with radiation field, density, temperature, and Fe abundance physical processes in the emitting regions. Our 340-model Fe II spectra are compared with available other models and observations.