Dwarf galaxies in CDM and SIDM with baryons: observational probes of the nature of dark matter

By M. Vogelsberger, J. Zavala, Christine Simpson, Adrian Jenkins Mit, D. C. Centre, Hits, Icc Durham. 2014

191 citations recorded by the source corpus.

We present the first cosmological simulations of dwarf galaxies, which include dark matter self-interactions and baryons. We study two dwarf galaxies within cold dark matter, and four different elastic self-interacting scenarios with constant and velocity-dependent cross-sections, motivated by a new force in the hidden dark matter sector. Our highest resolution simulation has a baryonic mass resolution of 1.8 × 102 M⊙ and a gravitational softening length of 34 pc at z = 0. In this first study we focus on the regime of mostly isolated dwarf galaxies with halo masses ∼ 1010 M⊙ where dark matter dynamically dominates even at sub-kpc scales. We find that while the global properties of galaxies of this scale are minimally affected by allowed self-interactions, their internal structures change significantly if the cross-section is large enough within the inner sub-kpc region. In these dark-matter-dominated systems, self-scattering ties the shape of the stellar distribution to that of the dark matter distribution. In particular, we find that the stellar core radius is closely related to the dark matter core radius generated by self-interactions. Dark matter collisions lead to dwarf galaxies with larger stellar cores and smaller stellar central densities compared to the cold dark matter case. The central metallicity within 1 kpc is also larger by up to ∼15 per cent in the former case. We conclude that the mass distribution and characteristics of the central stars in dwarf galaxies can potentially be used to probe the self-interacting nature of dark matter.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/ab72d46b8cc685a566496c95b423a0b367d2348e

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Citations in the corpus

Forged in FIRE: cusps, cores and baryons in low-mass dwarf galaxies (2015, background): “…and Governato et al. (2012) agree reasonably well, a different set of high resolution simulations with a simpler implementation of stellar feedback have not produced cores in dwarf galaxy halos at any mass (Vogelsberger et al. 2014), even though a number of other observables are well matched.”
The unexpected diversity of dwarf galaxy rotation curves (2015, background): “‘Baryon-induced’ cores in CDM haloes would be difficult to distinguish from those produced by other effects, such as collisional effects in the case of SIDM (see e.g. Vogelsberger et al. 2014b; Bastidas Fry et al. 2015), complicating matters further.”
NIHAO – IV: core creation and destruction in dark matter density profiles across cosmic time (2015, background): “This cusp-core controversy suggests that either a modification of the whole CDM paradigm is required (e.g., self interacting dark matter, SIDM, Vogelsberger et al. 2014), or the inadequacy of pure N-body simulations to capture the dark matter dynamics on small scales, due to the absence of…”
The APOSTLE simulations: solutions to the Local Group's cosmic puzzles (2015, unknown): “The lack of a single model able to reconcile all of the LG observations with CDM predictions has led to renewed interest in alternatives to CDM, such as warm (e.g. Lovell et al. 2012) or self-interacting dark matter (e.g. Rocha et al. 2013; Vogelsberger et al. 2014).”
The merger rate of galaxies in the Illustris simulation: a comparison with observations and semi-empirical models (2015, methodology): “…merger rate using the Illustris Simulation, a hydrodynamic cosmological simulation carried out in a periodic box of∼106.5 Mpc on a side, which has been shown to reproduce many important properties of galaxies at z = 0 (Vogelsberger et al. 2014a,b) as well as at higher redshifts (Genel et al. 2014).”
Small scale problems of the $\Lambda$CDM model: a short review (2016, methodology): “troversy on the impact of those baryonic processes on the dark halo, some claiming drastic feedback was needed to obtain the BTFR [136,137] while others reported no need for such feedback (see, e.g., [138,139]). Recently, the combination of the large EAGLE simulation programme [140,141] — calibrated”
ETHOS - an effective theory of structure formation: dark matter physics as a possible explanation of the small-scale CDM problems (2015, methodology): “It was also used to find that self-interactions can leave imprints in the stellar distribution of dwarf galaxies by performing the first SIDM simulation with baryons presented in Vogelsberger et al. (2014a).”
Core formation in dwarf haloes with self-interacting dark matter: no fine-tuning necessary (2014, background): “Further research, which is currently underway (Vogelsberger et al., 2014; Elbert et al., in preparation; Robles et al., in preparation), is also needed to investigate the effects of baryons on density profiles in an SIDM universe.”
Gravitational probes of dark matter physics (2017, background): “interacting dark matter nearly forms a cusp unlike the low-density cores found in dark-matter-only simulations [363, 416, 355, 356, 415, 407].”