Reconciling dwarf galaxies with ΛCDM cosmology: simulating a realistic population of satellites around a Milky Way-mass galaxy
- TAPIR, California Institute of Technology, Pasadena, CA (United States)
- Department of Physics and Astronomy and CIERA, Northwestern University, Evanston, IL (United States)
- Department of Physics, Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA (United States)
- Department of Astronomy and Theoretical Astrophysics Center, University of California, Berkeley, CA (United States)
Low-mass “dwarf” galaxies represent the most significant challenges to the cold dark matter (CDM) model of cosmological structure formation. Because these faint galaxies are (best) observed within the Local Group (LG) of the Milky Way (MW) and Andromeda (M31), understanding their formation in such an environment is critical. We present first results from the Latte Project: the Milky Way on Feedback in Realistic Environments (FIRE). This simulation models the formation of an MW-mass galaxy to z=0 within ΛCDM cosmology, including dark matter, gas, and stars at unprecedented resolution: baryon particle mass of 7070 M{sub ⊙} with gas kernel/softening that adapts down to 1 pc (with a median of 25--60 pc at z=0). Latte was simulated using the GIZMO code with a mesh-free method for accurate hydrodynamics and the FIRE-2 model for star formation and explicit feedback within a multi-phase interstellar medium. For the first time, Latte self-consistently resolves the spatial scales corresponding to half-light radii of dwarf galaxies that form around an MW-mass host down to M{sub star}≳10{sup 5} M{sub ⊙}. Latte’s population of dwarf galaxies agrees with the LG across a broad range of properties: (1) distributions of stellar masses and stellar velocity dispersions (dynamical masses), including their joint relation; (2) the mass–metallicity relation; and (3) diverse range of star formation histories, including their mass dependence. Thus, Latte produces a realistic population of dwarf galaxies at M{sub star}≳10{sup 5} M{sub ⊙} that does not suffer from the “missing satellites” or “too big to fail” problems of small-scale structure formation. We conclude that baryonic physics can reconcile observed dwarf galaxies with standard ΛCDM cosmology.
- OSTI ID:
- 22868784
- Journal Information:
- Astrophysical Journal Letters, Vol. 827, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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