The Horizon-AGN simulation: morphological diversity of galaxies promoted by AGN feedback Article Swipe
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· 2016
· Open Access
·
· DOI: https://doi.org/10.1093/mnras/stw2265
· OA: W2410976049
The interplay between cosmic gas accretion on to galaxies and galaxy mergers\ndrives the observed morphological diversity of galaxies. By comparing the\nstate-of-the-art hydrodynamical cosmological simulations Horizon-AGN and\nHorizon-noAGN, we unambiguously identify the critical role of active galactic\nnuclei (AGN) in setting up the correct galaxy morphology for the massive end of\nthe population. With AGN feedback, typical kinematic and morpho-metric\nproperties of galaxy populations as well as the galaxy-halo mass relation are\nin much better agreement with observations. Only AGN feedback allows massive\ngalaxies at the centre of groups and clusters to become ellipticals, while\nwithout AGN feedback those galaxies reform discs. It is the merger-enhanced AGN\nactivity that is able to freeze the morphological type of the post-merger\nremnant by durably quenching its quiescent star formation. Hence morphology is\nshown to be driven not only by mass but also by the nature of cosmic accretion:\nat constant galaxy mass, ellipticals are galaxies that are mainly assembled\nthrough mergers, while discs are preferentially built from the in situ star\nformation fed by smooth cosmic gas infall.\n
