Dr. Rok Roškar: Effects of Radiative Stellar Feedback on Disc Galaxy Formation

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   Effects of Radiative Stellar Feedback on Disc Galaxy Formation 

   Dr. Rok Roškar, Institute for Theoretical Physics, University of Zurich

Galaxy formation models rely strongly on various feedback mechanism to reproduce the observed baryonic scaling relations and galaxy morphologies. Although dwarf galaxy and giant elliptical properties can be explained using supernova and active galactic nucleus feedback respectively, Milky Way-sized galaxies still represent a challenge to current theories of galaxy formation. In this paper, we explore the possible role of stellar radiation feedback to regulate the main properties of disk galaxies such as our own Milky Way. We have performed a suite of cosmological simulations of the same halo, a ~Milky Way-like halo selected based on its rather typical mass accretion history from a large-scale cosmological box. We have implemented radiative feedback from young stars using a crude model of radiative transfer for ultraviolet (UV) and infrared (IR) radiation. We find that radiative feedback appears as a viable mechanism to regulate the baryon fraction in stars in massive galaxies, while simultaneously preserving a reasonable disc morphology. Our simulated discs nevertheless appear systematically too thick, hinting at the need for a more realistic treatment of radiative transfer as well as improved spatial and mass resolution.