A mass-dependent density profile for dark matter haloes including the influence of galaxy formation

Arianna Di Cintio, Chris B. Brook, Aaron A. Dutton, Andrea V. Macciò, Greg S. Stinson, Alexander Knebe

Research output: Contribution to journalArticle

Abstract

We introduce a mass-dependent density profile to describe the distribution of dark matter within galaxies, which takes into account the stellar-to-halo mass dependence of the response of dark matter to baryonic processes. The study is based on the analysis of hydrodynamically simulated galaxies from dwarf to Milky Way mass, drawn from the Making Galaxies In a Cosmological Context project, which have been shown to match a wide range of disc scaling relationships. We find that the best-fitting parameters of a generic double power-law density profile vary in a systematic manner that depends on the stellar-to-halo mass ratio of each galaxy. Thus, the quantity M*/Mhalo constrains the inner (γ ) and outer (β) slopes of dark matter density, and the sharpness of transition between the slopes (α), reducing the number of free parameters of the model to two. Due to the tight relation between stellar mass and halo mass, either of these quantities is sufficient to describe the dark matter halo profile including the effects of baryons. The concentration of the haloes in the hydrodynamical simulations is consistent with N-body expectations up to MilkyWay-mass galaxies, at which mass the haloes become twice as concentrated as compared with pure dark matter runs. This mass-dependent density profile can be directly applied to rotation curve data of observed galaxies and to semianalytic galaxy formation models as a significant improvement over the commonly used NFW profile.

Original languageEnglish (US)
Pages (from-to)2986-2995
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume441
Issue number4
DOIs
StatePublished - Jun 2014

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Keywords

  • Dark matter
  • Galaxies: evolution
  • Galaxies: formation
  • Hydrodynamics
  • Methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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