NIHAO – IV: core creation and destruction in dark matter density profiles across cosmic time

By É. Tollet, A. Macciò, A. Dutton, G. Stinson, Liang-Yao Wang, Camilla Penzo, T. Gutcke, T. Buck, X. Kang, C. Brook and 3 more. 2015

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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 Overall our results suggest that the notion of a universal density profile for dark matter haloes is no longer valid in the presence of galaxy formation.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/3f60633658452ea8924c9e749cb37b512267261d

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Citations in the corpus

Gravitational probes of dark matter physics (2017, result): “Despite differences in code and the implementation of semi-analytic star formation prescriptions, there are now largely consistent results about the sign of the effect of baryons on halos on dwarf scales [255, 284, 372, 373, 374, 375, 376, 377, 378, 379, 352, 261].”
Small-Scale Challenges to the ΛCDM Paradigm (2017, background): “The filled magenta stars and shaded purple band (to guide the eye) show the predicted inner density slopes from the NIHAO cosmological hydrodynamic simulations by Tollet et al. (2016).”
The hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2 (2018, background): “Although the slope of the density profile close to the centre can be reproduced in some feedback models (Tollet et al. 2016), it is unclear whether such a large core size is really attainable.”
Dark matter cores all the way down (2015, background): “Di Cintio et al. (2014) and Tollet et al. (2016) report a peak in core formation at ∼ 1010 M , with core formation ceasing below this mass scale; while Mashchenko et al. (2008), Madau et al. (2014), Oñorbe et al. (2015) and Verbeke et al. (2015) find substantial cores even in 109 M dwarfs.”
The quest for dual and binary supermassive black holes: A multi-messenger view (2019, background): “galaxies with realistic structural properties in galaxy formation simulations (Guedes et al., 2011; Munshi et al., 2013; Tollet et al., 2016; Sokołowska et al., 2017).”
FIRE in the field: Simulating the threshold of galaxy formation (2016, background): “∼ 106 M (Munshi et al. 2013; Ferrero et al. 2012; Moster et al. 2013; Behroozi et al. 2013; Tollet et al. 2016), comparable to the stellar masses of classical dwarf spheroidal satellites in the Local Group that can be studied in exquisite detail observationally.”
NIHAO - XI. Formation of ultra-diffuse galaxies by outflows (2016, methodology): “…to cause expansion not only of the central DM distribution in galaxies (e.g. Governato et al. 2010; Di Cintio et al. 2014a,b; Oñorbe et al. 2015; Tollet et al. 2016; Chan et al. 2015; Read et al. 2016), but also of the stellar one (e.g. Teyssier et al. 2013; ElBadry et al. 2016; Dutton et al.…”