{
  "id": "2004.06724",
  "version": "v1",
  "published": "2020-04-14T18:00:01.000Z",
  "updated": "2020-04-14T18:00:01.000Z",
  "title": "Simulations of the Milky Way's central molecular zone -- I. Gas dynamics",
  "authors": [
    "Robin G. Tress",
    "Mattia C. Sormani",
    "Simon C. O. Glover",
    "Ralf S. Klessen",
    "Cara D. Battersby",
    "Paul C. Clark",
    "H Perry Hatchfield",
    "Rowan J. Smith"
  ],
  "comment": "32 pages, 32 figures, submitted to MNRAS. A version with higher-resolution figures can be downloaded from the following link: http://www.ita.uni-heidelberg.de/~mattia/download/draft_gas.pdf. Movies of the simulations can be found at the following link: http://www.ita.uni-heidelberg.de/~mattia/movies_cmzsf.html",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We use hydrodynamical simulations to study the Milky Way's central molecular zone (CMZ), i.e. the star-forming nuclear ring at Galactocentric radii $R\\lesssim200$ pc. The simulations comprise the gas flow in a Milky Way barred potential out to $R=5$ kpc, which is necessary in order to capture the large-scale environment in which the CMZ is embedded and with which it is strongly interacting through the bar-driven inflow. The simulations also include a non-equilibrium time-dependent chemical network, gas self-gravity, and a sub-grid model for star formation and supernova feedback, all while reaching sub-parsec resolution in the densest regions. Our main findings are as follows: (1) The distinction between inner ($R\\lesssim120$ pc) and outer ($120\\lesssim R\\lesssim450$ pc) CMZ that is sometimes proposed in the literature is unnecessary. Instead, the CMZ is best described as single structure, namely a star-forming ring with outer radius $R\\simeq 200$ pc which is interacting directly with the dust lanes that mediate the bar-driven inflow. (2) This accretion can induce a significant tilt of the CMZ out of the plane. A tilted CMZ might provide an alternative explanation to the $\\infty$-shaped structure identified in Herschel data by Molinari et al. 2011. (3) The bar in our simulation efficiently drives an inflow from the Galactic disc ($R\\simeq 3$ kpc) down to the CMZ ($R\\simeq200$ pc) of the order of $1\\rm\\,M_\\odot\\,yr^{-1}$, consistent with observational determinations. (4) Self-gravity and supernovae feedback can drive an inflow from the CMZ inwards towards the circumnuclear disc of the order of $\\sim0.03\\,\\rm M_\\odot\\,yr^{-1}$. (5) We give a new interpretation for the 3D placement of the 20 and 50 km s$^{-1}$ clouds, according to which they are close ($R\\lesssim30$ pc) to the Galactic centre, but are also connected to the larger-scale streams at $R\\gtrsim100$ pc.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-04-14T18:00:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "milky ways central molecular zone",
      "simulation",
      "gas dynamics",
      "bar-driven inflow",
      "milky way barred potential"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 32,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}