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Revised optical classification of a sample of gamma-ray-emitting active galactic nuclei with GTC and VLT
Authors: Dalla Barba, B.; Foschini, L.; Berton, M.; Järvelä, E.; Marziani, P.; Ciroi, S.; Dalla Bontá, E.; Crepaldi, L.; Vietri, A.; Antón, S., Marcha, MJM; Condó, P.; Mazzucchelli, C.
Ref.: Astron. Astrophys. 705, A122 (2026)
Abstract: We report the results of the optical follow-up of a sample of gamma-ray-emitting active galactic nuclei (AGNs). New high-quality optical spectra were obtained using the Gran Telescopio Canarias with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy and the European Southern Observatory`s Very Large Telescope Unit Telescope 1 with the FOcal Reducer and low dispersion Spectrograph 2. From the analysis of these spectra, we confirmed the previous narrow-line Seyfert 1 (NLS1) classification for four objects and discovered two new NLS1s, bringing the total number of optically confirmed gamma-NLS1s to 26. We also identified two ambiguous cases between NLS1 and intermediate Seyfert (IS), three ISs, one broad-line Seyfert 1, and one Seyfert 2. Based on the new spectra, we calculated black hole masses ranging from 10(6.25) to 10(9.32) M-circle dot and Eddington ratios spanning 0.05 to 2.07. This reclassification provides support for the scenario in which AGNs with relatively low black hole masses are capable of launching powerful relativistic jets and contributes to our broader understanding of gamma-ray-emitting AGNs.
