Investigating the effects of fresh gas on the Active Galactic Nuclei luminosity of early- and late-type galaxies

TL;DR

This study investigates how the kinematic misalignment between stars and gas in galaxies influences the luminosity of active galactic nuclei, revealing that external accretion fuels AGN regardless of misalignment, with differences between galaxy types.

Contribution

It provides new insights into the relationship between gas-stellar kinematic misalignment and AGN luminosity across early- and late-type galaxies using integral field spectroscopy data.

Findings

No correlation between AGN luminosity and misalignment angle.

AGN in late-type galaxies show a wider luminosity range.

AGN in early-type galaxies are fueled by external gas regardless of misalignment.

Abstract

The main fuelling processes for Active Galactic Nuclei (AGN) are currently unknown. Previous work showed that galaxies with a large kinematic misalignment between their stellar and gas reservoirs have a higher AGN fraction than galaxies without misalignment. Such misalignment is a strong indication of a past galaxy interaction or an external accretion event. In this work we use integral field spectroscopy data from the SAMI and MaNGA surveys to investigate the AGN luminosity as a function of kinematic misalignment angle. Our sample of AGN exhibit bolometric luminosities in the range 10^40 to 10^43 erg/s, indicative of low to moderate luminosity AGN. We find no correlation between AGN luminosity as a function of misalignment for AGN host galaxies from both surveys. We find some differences between the AGN luminosity of early- and late-type AGN host galaxies (ETGs, LTGs). AGN in LTG hosts have a wider luminosity range, with most LTG hosts showing aligned stellar to gas kinematics. AGN in ETG hosts have a luminosity range that does not depend on misalignment angle, suggesting AGN in ETG hosts are consistent with being fuelled by external accretion events, irrespective of their stellar to gas kinematic misalignment. While all the AGN in ETGs in our sample are consistent with being activated and fuelled by external gas, the range of observed AGN luminosities is likely caused by secondary factors such as the amount of fresh gas brought into the galaxy by the external interaction.