The edge of galaxy formation - I. Formation and evolution of MW-satellite analogues before accretion

Andrea V. Macciò, Jonas Frings, Tobias Buck, Camilla Penzo, Aaron A. Dutton, Marvin Blank, Aura Obreja

Research output: Contribution to journalArticlepeer-review


The satellites of the Milky Way and Andromeda represent the smallest galaxies we can observe in our Universe. In this series of papers, we aim to shed light on their formation and evolution using cosmological hydrodynamical simulations. In this first paper, we focus on the galaxy properties before accretion, by simulating 27 haloes with masses between 5 × 108 and 1010M. Out of this set 19 haloes successfully form stars, while 8 remain dark. The simulated galaxies match quite well present day observed scaling relations between stellar mass, size and metallicity, showing that such relations are in place before accretion. Our galaxies show a large variety of star formation histories, from extended star formation periods to single bursts. As in more massive galaxies, large star formation bursts are connected with major mergers events, which greatly contribute to the overall stellar mass build up. The intrinsic stochasticity of mergers induces a large scatter in the stellar mass-halo mass relation, up to two orders of magnitude. Despite the bursty star formation history, on these mass scales baryons are very ineffective in modifying the dark matter profiles, and galaxies with a stellar mass below ≈106M retain their cuspy central dark matter distribution, very similar to results from pure N-body simulations.

Original languageEnglish (US)
Pages (from-to)2356-2366
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - 2017


  • Cosmology: theory
  • Dark matter
  • Galaxies: formation
  • Galaxies: kinematics and dynamics
  • Methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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