Theoretical FeI/II/III Emission-Line Strengths from Active Galactic Nuclei with Broad-Line Regions

摘要

We present theoretical iron emission line strengths for physical conditionstypical of Active Galactic Nuclei with Broad-Line Regions. The non-localthermodynamic equilibrium (NLTE) models include a new and extensive treatmentof radiative transfer in the FeIII ion, complementing the FeII emission linestrengths predicted in our earlier works. We also briefly present preliminaryresults for the FeI emission from AGN using a reduced atom model. We cansatisfactorily reproduce the empirical UV FeIII emission line template ofVestergaard & Wilkes (2001) for the prototypical narrow-line Seyfert 1 galaxy IZw 1, both in terms of the general FeIII flux distribution and the relativestrength of the FeIII and FeII emission. However, a number of detailed featuresare still not matched; the most prominent example is the strongest single FeIIIfeature observed in the I Zw 1 spectrum, UV47: it is predicted to be strongonly in models suppressing Fe-H charge exchange reactions. We examine the roleof variations in cloud turbulent velocity and iron abundance and carry outMonte Carlo simulations to demonstrate the effect of uncertainties in atomicdata on the computed spectra.