X-ray AGN Activity in Nearby Triple Galaxy Mergers

Multiple interacting AGN are signposts of ongoing galaxy formation, and represent rare instances where the link between environment and black hole growth (or, lack thereof) can be probed. There is now broad consensus that AGN play central roles in the evolution and enrichment of their surroundings, however, the processes that trigger the various forms of AGN activity remain unclear. Major galaxy mergers have been predicted to induce AGN, however, the results are still mixed. Recently, it has been shown that interacting triple galaxy systems are unique environments where AGN activity is enhanced. Studying the population of nearby triple galaxy systems is therefore critical to understanding the physical drivers behind SMBH accretion, and the link between environment and black hole growth. We present on recent results from new XMM-Newton Cycle 21 observations of 3 nearby triple galaxy mergers, where we find an elevated AGN fraction as compared to the nominal active fraction of non-interacting galaxies. Combining our XMM-Newton sample with past studies, we find that our new data support the previously found connection between the large-scale (kpc) gas levels and nuclear-scale (pc) dust levels, suggesting that large amount of both gas and dust can be efficiently funneled to the central regions of galaxies during triple galaxy mergers. Interestingly, the number of AGN in each triple galaxy system seems to be linked to these environmental properties, implying that triple galaxy mergers may be key moments for triggering SMBH accretion and growth.