Detection of faint broad emission lines in type 2 AGN - I. Near infrared observations and spectral fitting

We present medium resolution near-infrared spectroscopic observations of 41 obscured and intermediate class active galactic nuclei (AGN; type 2, 1.9 and 1.8; AGN2) with redshift z ≲ 0.1, selected from the $\textit{Swift}$/Burst Alert Telescope 70-month catalogue. The observations have been carried out in the framework of a systematic study of the AGN2 near-infrared spectral properties and have been executed using Infrared Spectrometer And Array Camera/VLT, X-shooter/VLT and LUCI/LBT, reaching an average S/N ratio of ∼30 per resolution element. For those objects observed with X-shooter, we also obtained simultaneous optical and UV spectroscopy. We have identified a component from the broad line region in 13 out of 41 AGN2, with full width at half-maximum (FWHM) > 800 km s$^{-1}$. We have verified that the detection of the broad line region components does not significantly depend on selection effects due to the quality of the spectra, the X-ray or near-infrared fluxes, the orientation angle of the host galaxy or the hydrogen column density measured in the X-ray band. The average broad line region components found in AGN2 has a significantly (a factor 2) smaller FWHM if compared with a control sample of type 1 AGN.

Keywords

galaxies: active, quasars: emission lines, galaxies: Seyfert, infrared: galaxies

Journal Title

Monthly Notices of the Royal Astronomical Society

Journal ISSN

0035-8711
1365-2966

Volume Title

464

Publisher

Oxford University Press

Publisher DOI

https://doi.org/10.1093/mnras/stw2368

Rights and licensing

Except where otherwised noted, this item's license is described as http://www.rioxx.net/licenses/all-rights-reserved

Sponsorship

Science and Technology Facilities Council (ST/M001172/1)

This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We acknowledge funding from PRIN/MIUR and PRIN/INAF. MB acknowledges support from the FP7 Career Integration Grant “eEASy” (CIG 321913).

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Scholarly Works - Physics
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