Properties and observables of massive galaxies in self-interacting dark matter cosmologies

Abstract

We use hydrodynamical cosmological simulations to test the differences between cold and self-interacting dark matter models (CDM and SIDM) in the mass range of massive galaxies ($10^{12}{M}_{\odot }{h}^{-1}<M<10^{13.5}{M}_{\odot }{h}^{-1}$). We consider two SIDM models: one with constant cross section $\sigma /m_{\chi }=1\mathrm{c}{\mathrm{m}}^2{\mathrm{g}}^{-1}$ and one where the cross section is velocity-dependent. We analyse the halo density profiles and concentrations, comparing the predictions of dark-matter-only and hydrodynamical simulations in all scenarios. We calculate the best-fit Einasto profiles and compare the resulting parameters with previous studies and define the best-fit concentration-mass relations. We find that the inclusion of baryons reduces the differences between different dark matter models with respect to the DM-only case. In SIDM hydro runs, deviations from the CDM density profiles weakly depend on mass: the most massive systems ($M>10^{13}{M}_{\odot }{h}^{-1}$) show cored profiles, while the least massive ones ($M<10^{12.5}{M}_{\odot }{h}^{-1}$) have cuspier profiles. Finally, we compare the predictions of our simulations to observational results, by looking at the dark matter fractions and the distribution of strong lensing Einstein radii. We find that in SIDM the DM-fractions decrease more rapidly with increasing stellar mass than in CDM, leading to lower fractions at $M_{\ast }>10^{11}{M}_{\odot }$, a distinctive signature of SIDM. At the same time, the distribution of Einstein radii, derived from both CDM and SIDM hydro runs, is comparable to observed samples of strong lenses with $M>10^{13}{M}_{\odot }{h}^{-1}$. We conclude that the interplay between self-interaction and baryons can greatly reduce the expected differences between CDM and SIDM models at this mass scale, and that techniques able to separate the dark and luminous mass in the inner regions of galaxies are needed to constrain self-interactions.

13 pages, 12 figures

References in corpus (17)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Dark matter and cosmic structure
• Warm dark matter chills out: constraints on the halo mass function and the free-streaming length of dark matter with 8 quadruple-image strong gravitational lenses
• An excess of small-scale gravitational lenses observed in galaxy clusters
• Constraining Velocity-dependent Self-Interacting Dark Matter with the Milky Way's dwarf spheroidal galaxies
• The effect of baryons on the inner density profiles of rich clusters
• Dark Matter Cores and Cusps in Spiral Galaxies and their Explanations
• The surprising accuracy of isothermal Jeans modelling of self-interacting dark matter density profiles
• Constraints on dark matter self-interaction from the internal density profiles of X-COP galaxy clusters
• Strong Dark Matter Self-interactions Diversify Halo Populations within and surrounding the Milky Way
• The probability of galaxy-galaxy strong lensing events in hydrodynamical simulations of galaxy clusters
• Constraining SIDM with halo shapes: revisited predictions from realistic simulations of early-type galaxies
• From dwarf galaxies to galaxy clusters: Self-Interacting Dark Matter over 7 orders of magnitude in halo mass
• ETHOS - an effective theory of structure formation: formation of the first haloes and their stars
• X-ray morphology of cluster-mass haloes in self-interacting dark matter

Cited by in corpus (12)

• A persistent excess of galaxy-galaxy strong lensing observed in galaxy clusters
• Dianoga SIDM: galaxy cluster self-interacting dark matter simulations
• Cosmological and idealized simulations of dark matter haloes with velocity-dependent, rare and frequent self-interactions
• Introducing the AIDA-TNG project: galaxy formation in alternative dark matter models
• Detecting low-mass haloes with strong gravitational lensing II: constraints on the density profiles of two detected subhaloes
• Numerical challenges for energy conservation in N-body simulations of collapsing self-interacting dark matter halos
• Testing the parametric model for self-interacting dark matter using matched halos in cosmological simulations
• Not All Subhaloes Are Created Equal: Modelling the Diversity of Subhalo Density Profiles in TNG50
• Exploring Self-Interacting Dark Matter Halos with Diverse Baryonic Distributions: A Parametric Approach
• A Universal Analytic Model for Gravitational Lensing by Self-Interacting Dark Matter Halos
• The AIDA-TNG project: 3D halo shapes
• The AIDA-TNG project: dark matter profiles and concentrations in alternative dark matter models