The impact of baryonic physics on the structure of dark matter haloes: The view from the FIRE cosmological simulations

T. K. Chan, D. Kereš, J. Oñorbe, P. F. Hopkins, A. L. Muratov, C. A. Faucher-Giguère, E. Quataert

Research output: Contribution to journalArticle

150 Scopus citations

Abstract

We study the distribution of cold dark matter (CDM) in cosmological simulations from the FIRE (Feedback In Realistic Environments) project, for M* ~ 104-11M galaxies in Mh ~ 109-12M haloes. FIRE incorporates explicit stellar feedback in the multiphase interstellar medium, with energetics from stellar population models. We find that stellar feedback, without 'fine-tuned' parameters, greatly alleviates small-scale problems in CDM. Feedback causes bursts of star formation and outflows, altering the DM distribution. As a result, the inner slope of the DM halo profile (α) shows a strong mass dependence: profiles are shallow at Mh ~ 1010-1011M and steepen at higher/lower masses. The resulting core sizes and slopes are consistent with observations. This is broadly consistent with previous work using simpler feedback schemes, but we find steeper mass dependence of α, and relatively late growth of cores. Because the star formation efficiency M*/Mh is strongly halo mass dependent, a rapid change in a occurs around Mh ~ 1010M (M* ~ 106-107M), as sufficient feedback energy becomes available to perturb the DM. Large cores are not established during the period of rapid growth of haloes because of ongoing DM mass accumulation. Instead, cores require several bursts of star formation after the rapid build-up has completed. Stellar feedback dramatically reduces circular velocities in the inner kpc of massive dwarfs; this could be sufficient to explain the 'Too Big To Fail' problem without invoking non-standard DM. Finally, feedback and baryonic contraction in Milky Way-mass haloes produce DM profiles slightly shallower than the Navarro-Frenk-White profile, consistent with the normalization of the observed Tully-Fisher relation.

Original languageEnglish (US)
Pages (from-to)2981-3001
Number of pages21
JournalMonthly Notices of the Royal Astronomical Society
Volume454
Issue number3
DOIs
StatePublished - 2015

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Dark matter
  • Galaxies: evolution
  • Galaxies: haloes
  • Galaxies: kinematics and dynamics
  • Galaxies: structure

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