An IFU View of the Active Galactic Nuclei in MaNGA Galaxy Pairs

TL;DR

This study investigates the prevalence and properties of active galactic nuclei (AGNs) in galaxy pairs using MaNGA survey data, finding no significant evolution in AGN fraction during mergers and suggesting AGNs follow inside-out quenching.

Contribution

It provides a detailed analysis of AGN occurrence and characteristics in galaxy pairs, highlighting their similar properties to isolated AGNs and their different star formation profiles compared to star-forming galaxies.

Findings

AGN fraction in pairs is similar to isolated galaxies (around 5%).

AGNs in pairs show inside-out quenching with increasing specific SFR outward.

Merger impact on star formation in AGNs is less prominent than in star-forming galaxies.

Abstract

The role of active galactic nuclei (AGNs) during galaxy interactions and how they influence the star formation in the system are still under debate. We use a sample of 1156 galaxies in galaxy pairs or mergers (hereafter `pairs') from the MaNGA survey. This pair sample is selected by the velocity offset, projected separation, and morphology, and is further classified into four cases along the merger sequence based on morphological signatures. We then identify a total of 61 (5.5%) AGNs in pairs based on the emission-line diagnostics. No evolution of the AGN fraction is found, either along the merger sequence or compared to isolated galaxies (5.0%). We observe a higher fraction of passive galaxies in galaxy pairs, especially in the pre-merging cases, and associate the higher fraction to their environmental dependence. The isolated AGN and AGN in pairs show similar distributions in their global stellar mass, star formation rate (SFR), and central [OIII] surface brightness. AGNs in pairs show radial profiles of increasing specific SFR and declining Dn4000 from center to outskirts, and no significant difference from the isolated AGNs. This is clearly different from star-forming galaxies (SFGs) in our pair sample, which show enhanced central star formation, as reported before. AGNs in pairs have lower Balmer decrements at outer regions, possibly indicating less dust attenuation. Our findings suggest that AGNs likely follow an inside-out quenching and the merger impact on the star formation in AGNs is less prominent than in SFGs.