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

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 1σsensitivity level of ∼0.15 mJy beam−1, 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.