The parametrization of gas flows in discs in the Auriga simulations

Abstract

We study the radial motions of cold, star-forming gas in the secular evolution phase of a set of 14 magnetohydrodynamical cosmological zoom-in simulations of Milky Way-mass galaxies. We study the radial transport of material within the disc plane in a series of concentric rings. For the gas in each ring at a given time we compute two quantities as a function of time and radius: 1) the radial bulk flow of the gas; and 2) the radial spread of the gas relative to the bulk flow. Averaging the data from all the halos, we find that the radial spread increases with radius in the form of a power law with strong secondary dependencies on the fraction of accreted material and the local radial velocity dispersion of the gas. We find that the bulk motion of gas is well described in the inner disc regions by a radially-independent mean inward flow speed of $-$2.4 km s${}^{-1}$. The spread around this value relates to the change in angular momentum of the gas and also the amount of accreted material. These scalings from fully cosmological, MHD simulations of galaxy formation can then be used in semi-analytic models to better parameterise the radial flow of gas in discs.

17 pages, 13 figures, Accepted for publication in MNRAS

References in corpus (9)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time
• The impact of feedback on cosmological gas accretion
• Gas accretion and galactic fountain flows in the Auriga cosmological simulations: angular momentum and metal re-distribution
• Building disc structure and galaxy properties through angular momentum: The DARK SAGE semi-analytic model
• Properties of HI discs in the Auriga cosmological simulations
• How to get cool in the heat: comparing analytic models of hot, cold, and cooling gas in haloes and galaxies with EAGLE
• L-GALAXIES 2020: The evolution of radial metallicity profiles and global metallicities in disc galaxies
• Radial Flows and Angular Momentum Conservation in Galactic Chemical Evolution

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• Stellar migration in the Auriga simulations
• Cosmological gas accretion history onto the stellar discs of Milky Way-like galaxies in the Auriga simulations -- (II) The inside-out growth of discs
• Radial Transport in High-Redshift Disk Galaxies Dominated by Inflowing Streams