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We present a study of FeII emission in the near-infrared region (NIR) for 25active galactic nuclei (AGNs) to obtain information about the excitationmechanisms that power it and the location where it is formed. We employ a NIRFeII template derived in the literature and found that it successfullyreproduces the observed FeII spectrum. The FeII bump at 9200 Angstroms detectedin all objects studied confirms that Lyman-alpha fluorescence is always presentin AGNs. The The correlation found between the flux of the 9200 Angstroms bump,the 1 micron lines and the optical FeII imply that Lyman-alpha fluorescenceplays an important role in the FeII production. We determined that at least 18%of the optical FeII is due to this process while collisional excitationdominates the production of the observed FeII. The line profiles of FeII 10502,OI 11287, CaII 8664 and Paschen-beta were compared to gather information aboutthe most likely location where they are emitted. We found that FeII, OI andCaII have similar widths and are, on average, 30% narrower than Paschen-beta.Assuming that the clouds emitting the lines are virialized, we show that theFeII is emitted in a region twice as far from the central source thanPaschen-beta. The distance though strongly varies: from 8.5 light-days forNGC4051 to 198.2 light-days for Mrk509. Our results reinforce the importance ofthe FeII in the NIR to constrain critical parameters that drive its physics andthe underlying AGN kinematics as well as more accurate models aimed atreproducing this complex emission.

The FeII emission in active galactic nuclei: excitation mechanisms and location of the emitting region