Impact of supernova feedback on the Tully-Fisher relation

Abstract

Context. Recent observational results have found a bend in the Tully-Fisher relation in such a way that low-mass systems lie below the linear relation described by more massive galaxies. Aims. We intend to investigate the origin of the observed features in the stellar and baryonic Tully-Fisher relations and analyse the role played by galactic outflows on their determination. Methods. Cosmological hydrodynamical simulations which include supernova feedback were performed in order to follow the dynamical evolution of galaxies. Results. We found that supernova feedback is a fundamental process for reproducing the observed trends in the stellar Tully-Fisher relation. Simulated slowly rotating systems tend to have lower stellar masses than those predicted by the linear fit to the massive end of the relation, consistently with observations. This feature is not present if supernova feedback is turned off. In the case of the baryonic Tully-Fisher relation, we also detect a weaker tendency for smaller systems to lie below the linear relation described by larger ones. This behaviour arises as a result of the more efficient action of supernovae in the regulation of the star formation process and in the triggering of powerful galactic outflows in shallower potential wells, which may heat up and/or expel part of the gas reservoir.