skip to main content

Title: BUILDING LATE-TYPE SPIRAL GALAXIES BY IN-SITU AND EX-SITU STAR FORMATION

We analyze the formation and evolution of the stellar components in ''Eris'', a 120 pc resolution cosmological hydrodynamic simulation of a late-type spiral galaxy. The simulation includes the effects of a uniform UV background, a delayed-radiative-cooling scheme for supernova feedback, and a star formation recipe based on a high gas density threshold. It allows a detailed study of the relative contributions of ''in-situ'' (within the main host) and ''ex-situ'' (within satellite galaxies) star formation to each major Galactic component in a close Milky Way analog. We investigate these two star-formation channels as a function of galactocentric distance, along different lines of sight above and along the disk plane, and as a function of cosmic time. We find that: (1) approximately 70% of today's stars formed in-situ; (2) more than two thirds of the ex-situ stars formed within satellites after infall; (3) the majority of ex-situ stars are found today in the disk and in the bulge; (4) the stellar halo is dominated by ex-situ stars, whereas in-situ stars dominate the mass profile at distances ≲ 5 kpc from the center at high latitudes; and (5) approximately 25% of the inner, r ≲ 20 kpc, halo is composed of in-situ stars thatmore » have been displaced from their original birth sites during Eris' early assembly history.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. Department of Astronomy and Astrophysics, University of California Santa Cruz, 1156 High St., Santa Cruz, CA 95064 (United States)
  3. Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-9057 Zurich (Switzerland)
Publication Date:
OSTI Identifier:
22364345
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; COSMOLOGY; DENSITY; DISTANCE; MASS; MILKY WAY; RADIATIVE COOLING; SATELLITES; STAR EVOLUTION; STARS