Dual AGNs on 100 kpc Scales from the Million Quasar Catalog

TL;DR

This study identifies and analyzes 173 new low-redshift dual AGNs, triplets, and quadruplets within 100 kpc from the Million Quasars Catalog, revealing their demographics, tidal features, and separation distributions to enhance understanding of galaxy and black hole coevolution.

Contribution

The paper presents a new sample of low-redshift dual AGNs, triplets, and quadruplets, expanding existing catalogs and providing detailed analysis of their properties and interactions.

Findings

16% of pairs show tidal features

Number of dual AGNs increases at lower redshifts

Most pairs have velocity differences below 300 km/s

Abstract

Research on dual active galactic nuclei (AGNs) is crucial for understanding the coevolution of galaxies and supermassive black holes. However, the current number of dual AGNs remains scarce. In this work, we selected 173 new dual AGNs, 4 AGN triplets, and 1 AGN quadruplet from the Million Quasars Catalog, all with low redshift ($z < 0.5$), a projected distance ($r_p$) of no more than 100 kpc, and a line-of-sight velocity difference ($|\Delta v|$) of less than 600 km s$^{-1}$, thus supplementing existing low-redshift dual AGNs demographics. Visual inspection of the optical images from the Dark Energy Spectroscopic Instrument Legacy Survey was performed for each pair, revealing that $\sim$16\% of pairs exhibit tidal features. Statistical analyses show an increasing number of dual AGNs with decreasing redshift, with velocity difference primarily at $|\Delta v| < $ 300 km s$^{-1}$, which is likely an artifact of our selection strategy. The tidal sample peaks as having 13 pairs at 5-20$h^{-1}_{70}$ kpc, but drops to 1 pair $> 55\,h^{-1}_{70}$ kpc. Our study also explores thewide separation ($r_p>10$ kpc) dual AGNs, finding 165 such systems, with 25 displaying clear tidal features. Furthermore, some extra galaxies, AGNs, and/or their candidates were found in the same regions of the pairs or multiplets forming interacting systems with these pairs or multiplets.