Description
In this talk we explore the intricate role of both galaxy-intrinsic and environmental factors in triggering radio AGN activity in the local Universe. We investigate the prevalence of radio AGN by combining radio observations from the LOFAR Two-Metre Sky Survey (LoTSS) data release 2 with optical data from the extensively characterised Sloan Digital Sky Survey (SDSS). The large samples allow us to break degeneracies between stellar mass, black hole mass, bulge mass, morphology, and environmental parameters, including both local and global galaxy density. Consistent with previous studies, our findings confirm that stellar mass is a primary driver of radio AGN prevalence. However, at fixed stellar masses, galaxy morphology plays only a small role, with the fraction of galaxies hosting a radio AGN being up to two times higher in elliptical galaxies than in spirals of the same mass. But environmental factors emerge as significant determinants for radio-AGN activity, even after controlling for the dependence on stellar mass. Specifically, global density has a stronger correlation with the percentage of galaxies with radio-AGN activity than local densities or tidal interactions. These results support a cooling-flow scenario in which AGN activity depends primarily on the thermodynamic properties of the available gas. Our work provides new insights into the demographic and environmental drivers of AGN activity and contributes to a more complete understanding of the complex mechanisms of gas inflows towards supermassive black holes that have emerged as essential for understanding AGN triggering and maintenance.
