MUSE adaptive-optics spectroscopy confirms dual active galactic nuclei and strongly lensed systems at sub-arcsec separation

TL;DR

This study uses advanced adaptive optics spectroscopy to confirm dual active galactic nuclei and strongly lensed systems at very close separations, providing the largest sample of such compact distant systems to date.

Contribution

First high-resolution spectroscopic confirmation of multiple dual AGN and lensed systems selected via Gaia Multi Peak technique at sub-arcsecond separations.

Findings

Confirmed 5 dual AGN and 2 lensed systems among 12 candidates.

All targets showed two components, validating the GMP selection method.

Discovered some of the most compact dual/lensed systems at z > 0.3.

Abstract

The novel Gaia Multi Peak (GMP) technique has proven to be able to successfully select dual and lensed AGN candidates at sub-arcsec separations. Both populations are important because dual AGN represent one of the central, still largely untested, predictions of lamdaCDM cosmology, and compact lensed quasars allow to probe the central regions of the lensing galaxies. In this work, we present high spatial resolution spectroscopy of twelve GMP-selected systems. We use the the adaptive-optics assisted integral-field spectrograph MUSE at VLT to resolve each system and study the nature of each component. All the targets reveal the presence of two components confirming the GMP selection. We classify five targets as dual AGN, two as lensed systems, and five as a chance alignment of a star and and AGN. Having separations between 0.30" and 0.86", these dual and lensed systems are, to date, among the most compact ever discovered at z >0.3. This is the largest sample of distant dual AGN with sub-arcsec separations ever presented in a single paper.