How cold is dark matter? Constraints from Milky Way satellites

Andrea V. Macciò, Fabio Fontanot

Research output: Contribution to journalLetterpeer-review


We test the luminosity function of Milky Way satellites as a constraint for the nature of dark matter particles. We perform dissipationless high-resolution N-body simulations of the evolution of Galaxy-sized halo in the standard cold dark matter model and in four warm dark matter (WDM) scenarios, with a different choice for the WDM particle mass mw. We then combine the results of the numerical simulations with semi-analytic models for galaxy formation, to infer the properties of the satellite population. Quite surprisingly, we find that even WDM models with relatively low mw values (2-5 keV) are able to reproduce the observed abundance of ultra faint (Mv < - 9) dwarf galaxies, as well as the observed relation between luminosity and mass within 300 pc. Our results suggest a lower limit of 1keV for thermal WDM, in broad agreement with previous results from other astrophysical observations such as Lyman α forest and gravitational lensing.

Original languageEnglish (US)
Pages (from-to)L16-L20
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
StatePublished - May 2010


  • Cosmology: dark matter
  • Cosmology: theory
  • Galaxies: haloes
  • Gravitation
  • Methods: N-body simulations
  • Methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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