Very Long Baseline Array Observations of Parsec-scale Radio Emission in Dual Active Galactic Nuclei

TL;DR

This study used VLBA radio observations to detect and analyze parsec-scale emission in four dual AGN systems, revealing new compact radio sources and insights into their emission mechanisms and the effects of galaxy merging.

Contribution

First VLBA detection of parsec-scale radio emission in two dual AGN components, providing detailed analysis of their emission origins and implications for galaxy evolution.

Findings

Two new compact radio components detected at parsec scales.

Radio emission in these components likely from compact jets.

Systematic X-ray deficit possibly due to tidal effects and viewing angles.

Abstract

It is believed that dual active galactic nuclei (dual AGN) will form during galaxies merge. Studying dual-AGN emission can provide valuable insights into galaxy merging and evolution. To investigate parsec-scale radio emission properties, we observed eight radio components of four selected dual-AGN systems using the Very Long Baseline Array (VLBA) at 5 GHz in multiple-phase-center mode. Among them, two compact radio components, labeled J0051+0020B and J2300-0005A, were detected clearly on parsec scales for the first time. However, the radio emission of the other six components was resolved out in the high-resolution images. We provided the values or upper limits of the brightness temperature and radio emission power, and analyzed the emission origins in detail for each target. Based on their physical properties reported in this work and in the literature, we suggest the radio emission in J0051+0020B and J2300-0005A originates primarily from compact jets, while the other six sources show more complex emission mechanisms. In addition, our VLBA observations suggest the systematic X-ray deficit in our dual-AGN sample is likely attributed to the tidally induced effect and possible viewing angle effect.