2019/08/31 by Cassandra Lochhaas, Greg L. Bryan, Yuan Li +3 · 1 citation
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #Hydrostatic equilibrium #Physics #RADIUS #Ram pressure #Star formation #Thermal #Thermodynamics #astro-ph.GA
paper · pdf · doi:10.1093/mnras/staa358
20 pages, 17 figures, accepted by MNRAS
arxiv created 2020/02/05 · openalex publication_date 2020/02/05 · arxiv updated 2020/02/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
ABSTRACT The circumgalactic medium (CGM) is closely linked to galaxy formation and evolution, but difficult to characterize observationally and typically poorly resolved in cosmological simulations. We use spherically symmetric, idealized, high-resolution simulations of the CGM in 1012 and 1011 M_\odot dark matter haloes to characterize the gas pressure, turbulent and radial velocities, and degree of thermal and effective dynamic pressure support in the overall CGM as well as in its high- and low-temperature phases. We find that the 1012 M_\odot halo contains a CGM mostly formed of a hot gas halo in hydrostatic equilibrium out of which cold gas condenses and falls on to the central galaxy, while the 1011 M_\odot halo’s CGM is not in hydrostatic equilibrium, has a wider spread of properties at a given galactocentric radius, does not have a clear separation of hot and cold phases, and is dominated by bulk motions. We also find that the degree of pressure support in the 1011 M_\odot halo is strongly dependent on the parameters of the galactic winds of the central galaxy. These results promote the idea that there is no ‘average’ CGM and care must be taken when setting the initial conditions for a small-box simulation of a patch of the CGM.