FeII emission in active galactic nuclei: results from NIR Spectroscopy
FeII comprises up to one third of the line emission in AGNs. For that reason it is an important coolant that needs to be taken into accountto fully understand the energetics of the broad line region (BLR). In thistalk I will discuss new approaches to study the excitation mechanisms ofthe FeII based on a semi-empirical template we derived in thenear-infrared region (NIR). We correlate the strength of the NIR andoptical iron lines to assess the relative contribution of the differentmechanisms that produces that emission. We found that in all casesLy_alpha fluorescence plays an important role, being a process that needsto be considered in any approach aimed at understanding this complexemission. We also compare the width of the individual FeII lines with thatof other lines emitted in BLR. Our results confirm previous assumptionsand results from variabilty studies that the gas responsible for the FeIIemission is the outer portion of the BLR.