Very Long Baseline Array Imaging of Type-2 Seyferts with Double-Peaked Narrow Emission Lines: Searches for Sub-kpc Dual AGNs and Jet-Powered Outflows

TL;DR

This study uses VLBA imaging to investigate the origins of double-peaked [O III] emission lines in type-2 AGNs, aiming to identify dual AGNs or jet-driven outflows at sub-kiloparsec scales.

Contribution

First high-resolution VLBA observations of a sample of double-peaked [O III] type-2 AGNs, providing insights into their radio structures and potential dual AGN or jet origins.

Findings

Six out of thirteen AGNs detected in radio emission.

Two AGNs show clear jet structures on parsec scales.

Radio-loud double-peaked AGNs may indicate jet activity.

Abstract

This paper presents Very Long Baseline Array (VLBA) observations of 13 double-peaked [O III] emission-line type-2 Active Galactic Nuclei (AGNs) at redshifts 0.06 < z < 0.41 (with a median redshift of z~0.15) identified in the Sloan Digital Sky Survey. Such double-peaked emission-line objects may result from jets or outflows from the central engine or from a dual AGN. The VLBA provides an angular resolution of <~10 pc at the distance of many of these galaxies, sufficient to resolve the radio emission from extremely close dual AGNs and to contribute to understanding the origin of double-peaked [O III] emission lines. Of the 13 galaxies observed at 3.6 cm (8.4 GHz), we detect six at a 1\sigma\ sensitivity level of ~0.15 mJy/beam, two of which show clear jet structures on scales ranging from a few milliarcseconds to tens of milliarcseconds (corresponding to a few pc to tens of pc at a median redshift of 0.15). We suggest that radio-loud double-peaked emission-line type-2 AGNs may be indicative of jet produced structures, but a larger sample of double-peaked [O III] AGNs with high angular resolution radio observations will be required to confirm this suggestion.