Properties of Local Group galaxies in hydrodynamical simulations of sterile neutrino dark matter cosmologies

Mark R. Lovell, Sownak Bose, Alexey Boyarski, Robert Crain, Carlos S. Frenk, Wojciech Hellwing, Aaron Ludlow, Julio Navarro, Oleg Ruchayskiy, Matthieu Schaller, Joop Schaye, Tom Theuns

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Abstract

We study galaxy formation in sterile neutrino dark matter models that differ significantly from both cold and from `warm thermal relic' models. We use the EAGLE code to carry out hydrodynamic simulations of the evolution of pairs of galaxies chosen to resemble the Local Group, as part of the APOSTLE simulations project. We compare cold dark matter (CDM) with two sterile neutrino models with 7 keV mass: one, the warmest among all models of this mass (LA120) and the other, a relatively cold case (LA10). We show that the lower concentration of sterile neutrino subhalos compared to their CDM counterparts makes the inferred inner dark matter content of galaxies like Fornax (or Magellanic Clouds) less of an outlier in the sterile neutrino cosmologies. In terms of the galaxy number counts the LA10 simulations are \emph{indistinguishable} from CDM when one takes into account halo-to-halo (or `simulation-to-simulation') scatter. In order for the LA120 model to match the number of Local Group dwarf galaxies, a higher fraction of low mass haloes is required to form galaxies than is predicted by the EAGLE simulations. As the census of the Local Group galaxies nears completion, this population may provide a strong discriminant between cold and warm dark matter models.
Original languageEnglish
Pages (from-to)4285-4298
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume468
Issue number4
Early online date16 Mar 2017
DOIs
Publication statusPublished - 1 Jul 2017

Keywords

  • dark matter
  • Local Group
  • wthods: numerical
  • galaxies: evolution
  • galaxies: high redshift
  • RCUK
  • STFC
  • ST/K00042X/1
  • ST/H008519/1
  • ST/K003267/1

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