Positive AGN feedback in the outskirts of nearby barred spiral galaxies?

TL;DR

This study provides observational evidence that low-luminosity AGN in nearby barred spiral galaxies may positively influence star formation in their outskirts, with higher star formation rates and dust attenuation compared to non-AGN galaxies.

Contribution

First observational comparison of star formation in outskirts of AGN-host and non-AGN galaxies using UV data, suggesting positive AGN feedback effects.

Findings

Higher star formation rate density in AGN-host galaxy outskirts

Slower decline of star formation with radius in AGN-hosts

Enhanced FUV attenuation indicating dust coupling with feedback

Abstract

Observational evidence regarding the impact of AGN feedback on star formation (SF) in non-jetted galaxies is limited. With the available high-resolution UV observations from AstroSat-UVIT, complemented by GALEX, we studied the SF properties in the outskirts ($>0.5R_{25}$) of six AGN-host galaxies and compared them with four non-AGN galaxies of similar morphology. We observed a higher SF rate density ($\Sigma_{\text{SFR}}$) for the UV knots in AGN-host galaxies, and it falls off less rapidly compared to non-AGN galaxies, suggesting positive AGN feedback in the outskirts of AGN-host galaxies. Additionally, FUV attenuation (A$_{\text{FUV}}$) is also enhanced in the outer regions and falls less rapidly in AGN-host compared to non-AGN, indicating that the feedback could be coupled with dust. We speculate that the radiation-pressure-driven and/or wind mode AGN feedback could be at play even in low-luminosity nearby AGN-host galaxies.