AGN Triality of Triple Mergers: Multi-wavelength Classifications

TL;DR

This study investigates triple galaxy mergers using multi-wavelength data, identifying multiple AGN systems and exploring the relationship between SMBH activity and merger environments, revealing trends in gas and dust behavior during mergers.

Contribution

It is the first to identify multiple AGN in triple mergers using combined archival multi-wavelength observations and analyze their environmental properties.

Findings

Identified 4 likely dual AGN systems in triple mergers.

Confirmed one triple AGN system, SDSS J0849+1114.

Found a correlation between gas/dust properties and AGN activity levels.

Abstract

We present results from a multi-wavelength analysis searching for multiple AGN systems in nearby (z<0.077) triple galaxy mergers. Combining archival Chandra, SDSS, WISE, and VLA observations, we quantify the rate of nearby triple AGN, as well as investigate possible connections between SMBH accretion and merger environments. Analyzing the multi-wavelength observations of 7 triple galaxy mergers, we find that 1 triple merger has a single AGN (NGC 3341); we discover, for the first time, 4 likely dual AGN (SDSS J1027+1749, SDSS J1631+2352, SDSS J1708+2153, and SDSS J2356-1016); we confirm one triple AGN system, SDSS J0849+1114; and 1 triple merger in our sample remains ambiguous (SDSS J0858+1822). Analyzing the WISE data, we find a trend of increasing N_H (associated with the primary AGN) as a function of increasing W1-W2 color, reflecting that the motions of gas and dust are coupled in merging environments, where large amount of both can be funneled into the active central region during mergers. Additionally, we find that the one triple AGN system in our sample has the highest levels of N_H and W1-W2 color, while the dual AGN candidates all have lower levels; these results are consistent with theoretical merger simulations that suggest higher levels of nuclear gas are more likely to activate AGN in mergers.