The role of baryons in self-interacting dark matter mergers

Abstract

Mergers of galaxy clusters are promising probes of dark matter (DM) physics. For example, an offset between the DM component and the galaxy distribution can constrain DM self-interactions. We investigate the role of the intracluster medium (ICM) and its influence on DM-galaxy offsets in self-interacting dark matter models. To this end, we employ Smoothed Particle Hydrodynamics + N-body simulations to study idealized setups of equal- and unequal-mass mergers with head-on collisions. Our simulations show that the ICM hardly affects the offsets arising shortly after the first pericentre passage compared to DM-only simulations. But later on, e.g. at the first apocentre, the offsets can be amplified by the presence of the ICM. Furthermore, we find that cross-sections small enough not to be excluded by measurements of the core sizes of relaxed galaxy clusters have a chance to produce observable offsets. We found that different DM models affect the DM distribution and also the galaxy and ICM distribution, including its temperature. Potentially, the position of the shock fronts, combined with the brightest cluster galaxies, provides further clues to the properties of DM. Overall our results demonstrate that mergers of galaxy clusters at stages about the first apocentre passage could be more interesting in terms of DM physics than those shortly after the first pericentre passage. This may motivate further studies of mergers at later evolutionary stages.

15 pages, 10 figures + appendices, accepted for publication in MNRAS

References in corpus (23)

• Array Programming with NumPy
• A direct empirical proof of the existence of dark matter
• Constraints on the Self-Interaction Cross-Section of Dark Matter from Numerical Simulations of the Merging Galaxy Cluster 1E 0657-5
• Dark Matter and Dark Radiation
• Cores in Dwarf Galaxies from Dark Matter with a Yukawa Potential
• Revealing the properties of dark matter in the merging cluster MACSJ0025.4-1222
• Is dark matter with long-range interactions a solution to all small-scale problems of ΛCDM cosmology?
• The speed of the `bullet' in the merging galaxy cluster 1E0657-56
• Simulating the Bullet Cluster
• SIMPle Dark Matter: Self-Interactions and keV Lines
• Self-Scattering for Dark Matter with an Excited State
• Hidden Sector Hydrogen as Dark Matter: Small-scale Structure Formation Predictions and the Importance of Hyperfine Interactions
• Cosmic particle colliders: simulations of self-interacting dark matter with anisotropic scattering
• MC^2: Constraining the Dark Matter Distribution of the Violent Merging Galaxy Cluster CIZA J2242.8+5301 by Piercing through the Milky Way
• The Semi-Classical Regime for Dark Matter Self-Interactions
• A Hydrodynamical Solution for the "Twin-Tailed" Colliding Galaxy Cluster "El Gordo"
• Understanding the radio relic emission in the galaxy cluster MACS J0717.5+3745: spectral analysis
• The Cosmological Simulation Code OpenGadget3 -- Implementation of Meshless Finite Mass
• Analytical model for cluster radio relics
• CRESCENDO: An on-the-fly Fokker-Planck Solver for Spectral Cosmic Rays in Cosmological Simulations
• Looking for dark matter trails in colliding galaxy clusters
• Sparse reconstruction of the merging A520 cluster system
• The structure of halos in Self-Interacting Cold Dark Matter models

Cited by in corpus (12)

• Cosmological and idealized simulations of dark matter haloes with velocity-dependent, rare and frequent self-interactions
• eROSITA clusters dynamical state and their impact on the BCG luminosity
• Dynamical friction from self-interacting dark matter
• Testing the parametric model for self-interacting dark matter using matched halos in cosmological simulations
• Simulations of galaxy cluster mergers with velocity-dependent, rare and frequent self-interactions
• Exploring Self-Interacting Dark Matter Halos with Diverse Baryonic Distributions: A Parametric Approach
• The cosmological analysis of X-ray cluster surveys: VI. Inference based on analytically simulated observable diagrams
• What Multiple Images Say About the Large-Scale Mass Maps of Galaxy Clusters
• N-body simulations of dark matter-baryon interactions
• Simulating realistic self-interacting dark matter models including small and large-angle scattering
• Merger of massive galaxy cluster CL0238.3+2005 at z~0.4: just after pericenter passage?
• Merging Galaxy Clusters and the Search for New Physics of Dark Matter: A Review