The impact of inelastic self-interacting dark matter on the dark matter structure of a Milky Way halo

Abstract

We study the effects of inelastic dark matter self-interactions on the internal structure of a simulated Milky Way (MW)-size halo. Self-interacting dark matter (SIDM) is an alternative to collisionless cold dark matter (CDM) which offers a unique solution to the problems encountered with CDM on sub-galactic scales. Although previous SIDM simulations have mainly considered elastic collisions, theoretical considerations motivate the existence of multi-state dark matter where transitions from the excited to the ground state are exothermic. In this work, we consider a self-interacting, two-state dark matter model with inelastic collisions, implemented in the Arepo code. We find that energy injection from inelastic self-interactions reduces the central density of the MW halo in a shorter timescale relative to the elastic scale, resulting in a larger core size. Inelastic collisions also isotropize the orbits, resulting in an overall lower velocity anisotropy for the inelastic MW halo. In the inner halo, the inelastic SIDM case (minor-to-major axis ratio $s\equiv c/a\approx 0.65$) is more spherical than the CDM ($s\approx 0.4$), but less spherical than the elastic SIDM case ($s\approx 0.75$). The speed distribution $f(v)$ of dark matter particles at the location of the Sun in the inelastic SIDM model shows a significant departure from the CDM model, with $f(v)$ falling more steeply at high speeds. In addition, the velocity kicks imparted during inelastic collisions produce unbound high-speed particles with velocities up to 500 km s${}^{-1}$ throughout the halo. This implies that inelastic SIDM can potentially leave distinct signatures in direct detection experiments, relative to elastic SIDM and CDM.

arXiv comment16 pages, 10 figures

References in corpus (72)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• Dark Matter Substructure in Galactic Halos
• Populating a cluster of galaxies - I. Results at z=0
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Observational evidence for self-interacting cold dark matter
• Simulating Galaxy Formation with the IllustrisTNG Model
• The Aquarius Project: the subhalos of galactic halos
• A Theory of Dark Matter
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Halo Formation in Warm Dark Matter Models
• Substructures in hydrodynamical cluster simulations
• The Inner Structure of LambdaCDM Halos I: A Numerical Convergence Study
• Response of dark matter halos to condensation of baryons: cosmological simulations and improved adiabatic contraction model
• Triaxial Modeling of Halo Density Profiles with High-resolution N-body Simulations
• Warm Dark Matter as a solution to the small scale crisis: new constraints from high redshift Lyman-alpha forest data
• Cosmological Simulations with Self-Interacting Dark Matter I: Constant Density Cores and Substructure
• Concentration, Spin and Shape of Dark Matter Haloes as a Function of the Cosmological Model: WMAP1, WMAP3 and WMAP5 results
• A Method for Measuring (Slopes of) the Mass Profiles of Dwarf Spheroidal Galaxies
• Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies
• Reconciling dwarf galaxies with LCDM cosmology: Simulating a realistic population of satellites around a Milky Way-mass galaxy
• The Cores of Dwarf Galaxy Halos
• The APOSTLE simulations: solutions to the Local Group's cosmic puzzles
• The Shape of Dark Matter Halos: Dependence on Mass, Redshift, Radius, and Formation
• Subhaloes in Self-Interacting Galactic Dark Matter Haloes
• New Constraints on the free-streaming of warm dark matter from intermediate and small scale Lyman-$\alpha$ forest data
• The Sagittarius Dwarf Galaxy: a Model for Evolution in a Triaxial Milky Way Halo
• Cosmological Simulations with Self-Interacting Dark Matter II: Halo Shapes vs. Observations
• The unexpected diversity of dwarf galaxy rotation curves
• Great Circle tidal streams: evidence for a nearly spherical massive dark halo around the Milky Way
• The dark and baryonic matter content of low surface brightness disk galaxies
• Constraining Self-Interacting Dark Matter with the Milky Way's dwarf spheroidals
• Substructure and halo density profiles in a Warm Dark Matter Cosmology
• Forged in FIRE: cusps, cores, and baryons in low-mass dwarf galaxies
• Internal and External Alignment of the Shapes and Angular Momenta of LCDM Halos
• Baryons Matter: Why Luminous Satellite Galaxies Have Reduced Central Masses
• The Phase-Space Density Profiles of Cold Dark Matter Halos
• Dark matter cores all the way down
• How the Self-Interacting Dark Matter Model Explains the Diverse Galactic Rotation Curves
• Cores in warm dark matter haloes: a Catch 22 problem
• ETHOS - An Effective Theory of Structure Formation: Dark matter physics as a possible explanation of the small-scale CDM problems
• Dark Matter Direct Detection with Non-Maxwellian Velocity Structure
• Phase-space structure in the local dark matter distribution and its signature in direct detection experiments
• A universal density slope - velocity anisotropy relation for relaxed structures
• Halo Cores and Phase Space Densities: Observational Constraints on Dark Matter Physics and Structure Formation
• The velocity function in the local environment from LCDM and LWDM constrained simulations
• Impact of baryon physics on dark matter structures: a detailed simulation study of halo density profiles
• The Shape of Dark Matter Haloes in the Aquarius Simulations: Evolution and Memory
• Constraints on the shape of the Milky Way dark matter halo from the Sagittarius stream
• Using the Milky Way satellites to study interactions between cold dark matter and radiation
• Planck Data Reconsidered
• The impact of baryons on the spins and shapes of dark matter haloes
• Dark matter response to galaxy formation
• Interacting Dark Matter disguised as Warm Dark Matter
• Shape of Dark Matter Haloes in the Illustris Simulation: Effects of Baryons
• Abundance of Field Galaxies
• Scattering, Damping, and Acoustic Oscillations: Simulating the Structure of Dark Matter Halos with Relativistic Force Carriers
• Baryonic clues to the puzzling diversity of dwarf galaxy rotation curves
• Galaxy Shapes and Intrinsic Alignments in The MassiveBlack-II Simulation
• Evaporating the Milky Way halo and its satellites with inelastic self-interacting dark matter
• Direct detection of self-interacting dark matter
• NIHAO project II: Halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations
• Expanded haloes, abundance matching and too-big-to-fail in the Local Group
• The diverse dark matter density at sub-kiloparsec scales in Milky Way satellites:implications for the nature of dark matter
• Galaxy-halo alignments in the Horizon-AGN cosmological hydrodynamical simulation
• Shapes of dark matter halos
• The structure and assembly history of cluster-size haloes in Self-Interacting Dark Matter
• Dark matter halos in the multicomponent model. I. Substructure
• Dark matter halos in the multicomponent model. II. Density profiles of galactic halos
• Dark matter haloes in the multicomponent model. III. From dwarfs to galaxy clusters

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• Constraining SIDM with halo shapes: revisited predictions from realistic simulations of early-type galaxies
• Endothermic self-interacting dark matter in Milky Way-like dark matter haloes
• Cosmological and idealized simulations of dark matter haloes with velocity-dependent, rare and frequent self-interactions
• Unraveling the interplay between SIDM and baryons in MW halos: defining where baryons dictate heat transfer
• The role of baryons in self-interacting dark matter mergers
• Manifesting hidden dynamics of a sub-component dark matter
• SIDM Concerto: Compilation and Data Release of Self-interacting Dark Matter Zoom-in Simulations
• Dark matter haloes in the multicomponent model. III. From dwarfs to galaxy clusters
• Cosmological simulations with rare and frequent dark matter self-interactions
• Unequal-mass mergers of dark matter haloes with rare and frequent self-interactions
• The Non-universal Pseudo Phase-Space Density Profiles of Symphony Host Halos
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