2015/07/31 by Édouard Tollet, Edouard Tollet, Andrea V. Macciò +14 · 5 citations
Engineering · Physics and Astronomy · #Astronomy #Astrophysics #CCD and CMOS Imaging Sensors #COSMIC cancer database #Cold dark matter #Cosmology and Gravitation Theories #Cuspy halo problem #Dark matter #Dark matter halo #Dwarf galaxy #Dwarf galaxy problem #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #Physics #RADIUS #Redshift #Virial theorem #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stv2856
11 pages, 13 figures. Corrected typo in table 2 (middle row) with respect to the version published in MNRAS
openalex publication_date 2016/01/14 · arxiv created 2019/05/06 · arxiv updated 2019/05/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We use the NIHAO (Numerical Investigation of Hundred Astrophysical Objects) cosmological simulations to investigate the effects of baryonic physics on the time evolution of dark matter central density profiles. The sample is made of ≈70 independent high-resolution hydrodynamical simulations of galaxy formation and covers a wide mass range: 1010 ≲ Mhalo/M⊙ ≲ 1012, i.e. from dwarfs to L⋆. We confirm previous results on the dependence of the inner dark matter density slope, α, on the ratio between stellar-to-halo mass, Mstar/Mhalo. We show that this relation holds approximately at all redshifts (with an intrinsic scatter of ∼0.18 in α measured between 1 and 2 per cent of the virial radius). This implies that in practically all haloes the shape of their inner density profile changes quite substantially over cosmic time, as they grow in stellar and total mass. Thus, depending on their final Mstar/Mhalo ratio, haloes can either form and keep a substantial density core (Rcore ∼ 1 kpc), or form and then destroy the core and recontract the halo, going back to a cuspy profile, which is even steeper than cold-dark-matter predictions for massive galaxies (1012 M⊙). We show that results from the NIHAO suite are in good agreement with recent observational measurements of α in dwarf galaxies. Overall our results suggest that the notion of a universal density profile for dark matter haloes is no longer valid in the presence of galaxy formation.