How does the presence of bar affects the fueling of supermassive black holes? An IllustrisTNG100 perspective

Abstract

We conducted a statistical study of black hole masses of barred and unbarred galaxies in the IllustrisTNG100 cosmological magnetohydrodynamical simulations. This work aims to understand the role of the bars in the growth of central supermassive black hole mass and its implications on AGN fueling. Our sample consists of 1191 barred galaxies and 2738 unbarred galaxies in the IllustrisTNG100 simulations. To have an unbiased study, we perform our analysis with an equal number of barred and unbarred galaxies by using various controlled parameters like total galaxy mass, stellar mass, gas mass, dark matter halo mass, etc. Except for the stellar mass controlling, we find that the median of the black hole mass distribution for barred galaxies is higher than that of the unbarred ones, indicating that stellar mass is a key parameter influencing the black hole growth. The higher mean accretion rate of the black holes in barred galaxies, averaged since the bar forming epoch (z ∼ 2), explains the higher mean black hole masses in barred galaxies. Further, we also test that these results are unaffected by other environmental processes like minor/major merger histories and neighbouring gas density of black hole. Although the relationship between stellar mass, bar formation, and black hole growth is complex, with various mechanisms involved, our analysis suggests that bars can play a crucial role in feeding black holes, particularly in galaxies with massive stellar discs.