Searching for Dual Active Galactic Nuclei

TL;DR

This paper compiles an updated list of dual active galactic nuclei (DAGN) and presents preliminary radio observations, including a potential binary SMBH system and a merging galaxy with dual radio cores, advancing the search for DAGN.

Contribution

It provides an updated DAGN catalog and reports new radio observations, including a precessing jet model fitting and dual radio cores, offering insights into DAGN detection methods.

Findings

Detection of a precessing jet possibly due to a binary SMBH.

Identification of a merging galaxy with two radio cores separated by 5.6 kpc.

Presentation of an updated list of DAGN from published data.

Abstract

Binary or dual active galactic nuclei (DAGN) are expected from galaxy formation theories. However, confirmed DAGN are rare and finding these systems has proved to be challenging. Recent systematic searches for DAGN using double-peaked emission lines have yielded several new detections. As have the studies of samples of merging galaxies. In this paper, we present an updated list of DAGN compiled from published data. We also present preliminary results from our ongoing Expanded Very Large Array (EVLA) radio study of eight double- peaked emission-line AGN (DPAGN). One of the sample galaxy shows an S-shaped radio jet. Using new and archival data, we have successfully fitted a precessing jet model to this radio source. We find that the jet precession could be due to a binary AGN with a super-massive black-hole (SMBH) separation of 0.02 pc or a single AGN with a tilted accretion disk. We have found that another sample galaxy, which is undergoing a merger, has two radio cores with a projected separation of 5.6 kpc. We discuss the preliminary results from our radio study.