{
  "id": "1902.05553",
  "version": "v1",
  "published": "2019-02-14T19:00:00.000Z",
  "updated": "2019-02-14T19:00:00.000Z",
  "title": "First Results from the TNG50 Simulation: The evolution of stellar and gaseous disks across cosmic time",
  "authors": [
    "Annalisa Pillepich",
    "Dylan Nelson",
    "Volker Springel",
    "Ruediger Pakmor",
    "Paul Torrey",
    "Rainer Weinberger",
    "Mark Vogelsberger",
    "Federico Marinacci",
    "Shy Genel",
    "Arjen van der Wel",
    "Lars Hernquist"
  ],
  "comment": "Submitted to MNRAS. Highlights: Figures 9, 14, 15. See companion paper by Nelson et al. submitted today. Visuals at http://www.tng-project.org. Comments welcome",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "We present a new cosmological, magnetohydrodynamical simulation for galaxy formation: TNG50, the third and final installment of the IllustrisTNG project. TNG50 evolves 2x2160^3 dark-matter particles and gas cells in a volume 50 comoving Mpc across. It hence reaches a numerical resolution typical of zoom-in simulations, with a baryonic element mass of 8.5x10^4 Msun and an average cell size of 70-140 parsecs in the star-forming regions of galaxies. Simultaneously, TNG50 samples ~700 (6,500) galaxies with stellar masses above 10^10 (10^8) Msun at z=1. Here we investigate the structural and kinematical evolution of star-forming galaxies across cosmic time (0.5 < z < 6). We quantify their sizes, disk heights, 3D shapes, and degree of rotational vs. dispersion-supported motions as traced by rest-frame V-band light (i.e. roughly stellar mass) and by Halpha light (i.e. star-forming and dense gas). The unprecedented resolution of TNG50 enables us to model galaxies with sub-kpc half-light radii and with <300-pc disk heights. Coupled with the large-volume statistics, we characterize a diverse, redshift- and mass-dependent structural and kinematical morphological mix of galaxies all the way to early epochs. Our model predicts that for star-forming galaxies the fraction of disk-like morphologies, based on 3D stellar shapes, increases with both cosmic time and galaxy stellar mass. Gas kinematics reveal that the vast majority of 10^9-11.5 Msun star-forming galaxies are rotationally-supported disks for most cosmic epochs (Vmax/sigma>2-3, z<5), being dynamically hotter at earlier epochs (z>1.5). Despite large velocity dispersion at high redshift, cold and dense gas in galaxies predominantly arranges in disky or elongated shapes at all times and masses; these gaseous components exhibit rotationally-dominated motions far exceeding the collisionless stellar bodies.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-02-14T19:00:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "cosmic time",
      "first results",
      "tng50 simulation",
      "gaseous disks",
      "despite large velocity dispersion"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}