A systematic search for hidden type 1 AGNs: gas kinematics and scaling relations

Abstract

We search type 1 AGNs among emission-line galaxies, that are typically classified as type 2 AGNs based on emission line flux ratios if a broad component in the H$\alpha$ line profile is not properly investigated. Using ~24,000 type 2 AGNs at z $<$0.1 initially selected from Sloan Digital Sky Survey Data Release 7 by Bae, et al. 2014, we identify a sample of 611 type 1 AGNs based on the spectral fitting results and visual inspection. These hidden type 1 AGNs have relatively low luminosity with a mean broad \Ha\ luminosity, log L$_{\rm H\alpha }$ $=$ 40.73$\pm$0.32 \ergs\, and low Eddington ratio with a mean log L$_{bol}$/L$_{\rm Edd}$ $=$ -2.04$\pm$0.34, while they do follow the black hole mass - stellar velocity dispersion relation defined by the inactive galaxies and the reverberation-mapped type 1 AGNs. We investigate ionized gas outflows based on the [OIII] $\lambda$5007 kinematics, which show relatively high velocity dispersion and velocity shift, indicating that the line-of-sight velocity and velocity dispersion of the ionized gas in type 1 AGNs is on average larger than that of type 2 AGNs.