Dual AGN candidates with double-peaked [O III] lines matching that of confirmed dual AGNs

TL;DR

This study identifies 77 dual AGN candidates in SDSS quasars with z<0.25 using spectral analysis of double-peaked [O III] lines, with most candidates showing AGN activity and signs of tidal interaction.

Contribution

The paper introduces a spectral decomposition method to identify dual AGN candidates based on double-peaked [O III] lines, expanding the catalog of potential dual AGNs.

Findings

77 DAGN candidates identified from 1271 SDSS quasars.

Over 90% of candidates are confirmed AGNs via optical and mid-infrared diagnostics.

Approximately one-third show signs of tidal interaction in imaging data.

Abstract

We have performed a spectral decomposition to search for dual active galactic nuclei (DAGNs) in the Sloan Digital Sky Survey (SDSS) quasars with $z<0.25$. Potential DAGN candidates are searched by referencing velocity offsets and spectral shapes of double-peaked [O III] lines of known DAGNs. Out of 1271 SDSS quasars, we have identified 77 DAGN candidates. Optical and mid-infrared diagnostic diagrams are used to investigate the ionizing source in the DAGN candidates. The optical diagnostic analysis suggests 93\% of them are powered by AGNs, and mid-infrared diagnostic analysis suggests 97\% are powered by AGNs. About 1/3 of the SDSS images of the DAGN candidates show signs of tidal interaction, but we are unable to identify double nuclei in most of them due to the low spatial resolution of the archival imaging data available for most of the sample. The radio-loud fraction of the DAGN candidates ($\sim$10\%) is similar to that of typical AGNs.