FeII emission in active galactic nuclei: results from NIR
Spectroscopy
Alberto Rodriguez Ardila (LNA)
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 account to
fully understand the energetics of the broad line region (BLR). In this talk
I will discuss new approaches to study the excitation mechanisms of the FeII
based on a semi-empirical template we derived in the near-infrared region
(NIR). We correlate the strength of the NIR and optical iron lines to assess
the relative contribution of the different mechanisms that produces that
emission. We found that in all cases Ly_alpha fluorescence plays an
important role, being a process that needs to be considered in any
approach aimed at understanding this complex emission. We also compare the
width of the individual FeII lines with that of other lines emitted in
BLR. Our results confirm previous assumptions and results from variabilty
studies that the gas responsible for the FeII emission is the outer
portion of the BLR.