Very long baseline interferometry observation of the triple AGN candidate J0849+1114

TL;DR

This study used high-resolution VLBI radio observations to confirm the presence of an active galactic nucleus in one of the three interacting galaxies in the J0849+1114 system, supporting the idea of multiple black hole activity during galaxy mergers.

Contribution

First high-resolution VLBI observation of the triple AGN candidate J0849+1114, confirming an active nucleus in the easternmost galaxy and providing insights into AGN activity in merging systems.

Findings

Detected a compact radio source indicating an active galactic nucleus.

Confirmed the radio emission originates from an AGN, not star formation.

Identified significant flux density associated with the AGN at 100 milliarcsecond scale.

Abstract

In the hierarchical structure formation model, galaxies grow through various merging events. Numerical simulations indicate that the mergers can enhance the activity of the central supermassive black holes in the galaxies. Pfeifle et al. (2019a) identified a system of three interacting galaxies, J0849$+$1114, and provided multiwavelength evidence of all three galaxies containing active galactic nuclei. The system has substantial radio emission, and with high-resolution radio interferometric observation we aimed to investigate its origin, whether it is related to star formation or to one or more of the active galactic nuclei in the system. We performed high-resolution continuum observation of J0849$+$1114 with the European Very Long Baseline Interferometry Network at $1.7$ GHz. We detected one compact radio emitting source at the position of the easternmost nucleus. Its high brightness temperature and radio power indicate that the radio emission originates from a radio-emitting active galactic nucleus. Additionally, we found that significant amount of flux density is contained in $\sim 100$ milliarcsec-scale feature related to the active nucleus.