SDSS-IV MaNGA: How Galaxy Interactions Influence Active Galactic Nuclei

TL;DR

This study uses MaNGA survey data to analyze how galaxy interactions influence the activation of active galactic nuclei, revealing that tidal forces significantly boost AGN activity at close separations.

Contribution

It provides a quantitative model of tidally induced and correlated AGN triggering as a function of galaxy separation, highlighting the subtlety of distinguishing different AGN fueling mechanisms.

Findings

Tidal interactions induce about 30% more AGN at ~10 kpc separation.

Approximately 12% of offset AGN become dual AGN due to correlations.

AGN luminosities are similar in pairs and isolated galaxies, indicating stochastic fueling dominates.

Abstract

We present a comparative study of active galactic nuclei (AGN) between galaxy pairs and isolated galaxies with the final data release of the MaNGA integral field spectroscopic survey. We build a sample of 391 kinematic galaxy pairs within the footprint of the survey and select AGN using the survey's spectra. We use the comoving volume densities of the AGN samples to quantify the effects that tidal interactions have on the triggering of nuclear accretion. Our hypothesis is that the pair sample contains AGN that are triggered by not only stochastic accretion but also tidally induced accretion and correlated accretion. With the level of stochastically triggered AGN fixed by the control sample, we model the strength of tidally induced accretion and correlated accretion as a function of projected separation (rp) and compare the model expectations with the observed volume densities of dual AGN and offset AGN (single AGN in a pair). At rp ~ 10 kpc, we find that tidal interactions induce ~30% more AGN than stochastic fueling and cause ~12% of the offset AGN to become dual AGN because of correlations. The strength of both these effects decreases with increasing rp. We also find that the OIII luminosities of the AGN in galaxy pairs are consistent with those found in isolated galaxies, likely because stochastically fed AGN dominate even among close pairs. Our results illustrates that while we can detect tidally induced effects statistically, it is challenging to separate tidally induced AGN and stochastically triggered AGN in interacting galaxies.