Effects of coupled dark energy on the Milky Way and its satellites

Camilla Penzo, Andrea V. Macció, Marco Baldi, Luciano Casarini, Jose Oñorbe, Aaron A. Dutton

Research output: Contribution to journalArticle

Abstract

We present the first numerical simulations in coupled dark energy cosmologies with high enough resolution to investigate the effects of the coupling on galactic and subgalactic scales. We choose two constant couplings and a time-varying coupling function and we run simulations of three Milky Way-sized haloes (∼1012 M⊙), a lower mass halo (6 × 1011 M⊙) and a dwarf galaxy halo (5 × 109 M⊙).We resolve each halo with several million dark matter particles. On all scales, the coupling causes lower halo concentrations and a reduced number of substructures with respect to Λ cold dark matter (ΛCDM). We show that the reduced concentrations are not due to different formation times. We ascribe them to the extra terms that appear in the equations describing the gravitational dynamics. On the scale of the Milky Way satellites, we show that the lower concentrations can help in reconciling observed and simulated rotation curves, but the coupling values necessary to have a significant difference from ΛCDM are outside the current observational constraints. On the other hand, if other modifications to the standard model allowing a higher coupling (e.g. massive neutrinos) are considered, coupled dark energy can become an interesting scenario to alleviate the small-scale issues of the ΛCDM model.

Original languageEnglish (US)
JournalMonthly Notices of the Royal Astronomical Society
Volume461
Issue number3
DOIs
StatePublished - Sep 21 2016

    Fingerprint

Keywords

  • Dark energy
  • Dark matter
  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: haloes
  • Methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this