2020/02/24 by Evan E. Schneider, Eve C. Ostriker, Brant E. Robertson +1 · 1 citation
Physics and Astronomy · #Acceleration #Astronomy and Astrophysical Research #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #Mixing (physics) #Outflow #Quasar #Radiation pressure #Ram pressure #Spectral line #Supernova #Supersonic speed #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/ab8ae8
29 pages, 21 figures. Submitted to ApJ. Comments welcome
arxiv created 2020/02/24 · openalex publication_date 2020/05/01 · openalex created_date 2020/05/29 · arxiv updated 2020/06/03 · openalex updated_date 2026/08/05
Abstract We present the fourth simulation of the Cholla Galactic OutfLow Simulations suite. Using a physically motivated prescription for clustered supernova feedback, we successfully drive a multiphase outflow from a disk galaxy. The high resolution (<5 pc) across a relatively large domain (20 kpc) allows us to capture the hydrodynamic mixing and dynamical interactions between the hot and cool ( T ∼ 10 4 K) phases in the outflow, which in turn leads to direct evidence of a qualitatively new mechanism for cool gas acceleration in galactic winds. We show that mixing of momentum from the hot phase to the cool phase accelerates the cool gas to 800 km s −1 on kiloparsec scales, with properties inconsistent with the physical models of ram pressure acceleration or bulk cooling from the hot phase. The mixing process also affects the hot phase, modifying its radial profiles of temperature, density, and velocity from the expectations of radial supersonic flow. This mechanism provides a physical explanation for the high-velocity, blueshifted, low-ionization absorption lines often observed in the spectra of starburst and high-redshift galaxies.