2019MNRAS.482.5125H -
Mon. Not. R. Astron. Soc., 482, 5125-5137 (2019/February-1)
What drives the evolution of gas kinematics in star-forming galaxies?
HUNG C.-L., HAYWARD C.C., YUAN T., BOYLAN-KOLCHIN M., FAUCHER-GIGUERE C.-A., HOPKINS P.F., KERES D., MURRAY N. and WETZEL A.
Abstract (from CDS):
One important result from recent large integral field spectrograph (IFS) surveys is that the intrinsic velocity dispersion of galaxies traced by star-forming gas increases with redshift. Massive, rotation-dominated discs are already in place at z ∼ 2, but they are dynamically hotter than spiral galaxies in the local Universe. Although several plausible mechanisms for this elevated velocity dispersion (e.g. star formation feedback, elevated gas supply, or more frequent galaxy interactions) have been proposed, the fundamental driver of the velocity dispersion enhancement at high redshift remains unclear. We investigate the origin of this kinematic evolution using a suite of cosmological simulations from the FIRE (Feedback In Realistic Environments) project. Although IFS surveys generally cover a wider range of stellar masses than in these simulations, the simulated galaxies show trends between intrinsic velocity dispersion (σintr), SFR, and z in agreement with observations. In both observations and simulations, galaxies on the star-forming main sequence have median σintr values that increase from z ∼ 0 to z ∼ 1-1.5, but this increasing trend is less evident at higher redshift. In the FIRE simulations, σintr can vary significantly on time-scales of ≲¡ 100 Myr. These variations closely mirror the time evolution of the SFR and gas inflow rate ({dot}M_ gas_). By cross-correlating pairs of σintr, {dot}M_ gas_, and SFR, we show that increased gas inflow leads to subsequent enhanced star formation, and enhancements in σintr tend to temporally coincide with increases in {dot}M_ gas_ and SFR.
Abstract Copyright:
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
galaxies: evolution - galaxies: kinematics and dynamics - galaxies: structure
Simbad objects:
1
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