A New Method to Simulate Dark Matter-Baryon Interactions and Application to an Isolated Disk Galaxy

Abstract

We report on a new method for incorporating interactions between dark matter (DM) and baryons in cosmological simulations, capable of handling the challenging regime in which the dark matter particle mass is comparable to or lighter than the baryon mass. The method hybridizes two distinct approaches: gas particles receive momentum and energy transfer according to a mean-field calculation while DM particles undergo Monte Carlo scatterings. These approaches are derived from the Boltzmann equation and shown to be statistically equivalent. We present an open-source implementation of this method in the simulation code GIZMO. As a first application, we investigate the effects of DM-baryon interactions on an isolated Milky Way-like disk galaxy for dark matter having twice the proton mass, which roughly maximizes the average energy transfer per collision. For cross sections of order 1 barn ($10^{-24}$ cm${}^2$), these interactions cause strong changes to the mass distribution in the center of the galaxy in less than 1 Gyr, even when bar formation is suppressed by hand. For cross sections typical of hadronic interactions ($\lesssim 30$ mb), high-fidelity galaxy formation simulations will be needed to assess the effects on observable features of galaxies.

28 pages, 15 figures; v2: major revision; v3: corrects error in introduction; v4: accepted to ApJ, Figures 2-10 updated (simulations re-run)

References in corpus (40)

• The cosmological simulation code GADGET-2
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Observational evidence for self-interacting cold dark matter
• Small-Scale Challenges to the $\Lambda$CDM Paradigm
• GIZMO: A New Class of Accurate, Mesh-Free Hydrodynamic Simulation Methods
• FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation
• Dark Matter Self-interactions and Small Scale Structure
• Cosmological Simulations with Self-Interacting Dark Matter I: Constant Density Cores and Substructure
• First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment
• Grackle: a Chemistry and Cooling Library for Astrophysics
• Milky Way Satellite Census. III. Constraints on Dark Matter Properties from Observations of Milky Way Satellite Galaxies
• Constraining Dark Matter-Baryon Scattering with Linear Cosmology
• Molecular Hydrogen and Global Star Formation Relations in Galaxies
• The CAMELS project: Cosmology and Astrophysics with MachinE Learning Simulations
• Probing sub-GeV Dark Matter-Baryon Scattering with Cosmological Observables
• Exploring the effects of galaxy formation on matter clustering through a library of simulation power spectra
• Dark Matter Search Results from 4.2 Tonne-Years of Exposure of the LUX-ZEPLIN (LZ) Experiment
• Constraints on scattering of keV--TeV dark matter with protons in the early Universe
• A Critical Assessment of CMB Limits on Dark Matter-Baryon Scattering: New Treatment of the Relative Bulk Velocity
• The AGORA High-Resolution Galaxy Simulations Comparison Project. II: Isolated Disk Test
• Cosmological Constraints on Dark Matter Interactions with Ordinary Matter
• First Cosmological Constraint on the Effective Theory of Dark Matter-Proton Interactions
• Dark Matter Cores and Cusps in Spiral Galaxies and their Explanations
• A Window in the Dark Matter Exclusion Limits
• Gas-rich dwarf galaxies as a new probe of dark matter interactions with ordinary matter
• Bar-formation as driver of gas inflows in isolated disc galaxies
• Bounds on velocity-dependent dark matter-proton scattering from Milky Way satellite abundance
• No room to hide: implications of cosmic-ray upscattering for GeV-scale dark matter
• Closing the window on $\sim$GeV Dark Matter with moderate ($\sim$$\mu$b) interaction with nucleons
• A Search for Low-mass Dark Matter via Bremsstrahlung Radiation and the Migdal Effect in SuperCDMS
• $S_8$ Tension in the Context of Dark Matter-Baryon Scattering
• Cosmic-ray dark matter confronted by constraints on new light mediators
• Boltzmann-Fokker-Planck formalism for dark-matter--baryon scattering
• Astrophysical Tests of Dark Matter Self-Interactions
• Numerical Challenges in Modeling Gravothermal Collapse in Self-Interacting Dark Matter Halos
• Exact treatment of weak dark matter-baryon scattering for linear-cosmology observables
• Bounds on Velocity-Dependent Dark Matter-Baryon Scattering from Large-Scale Structure
• Numerical solution of the exact background collisional Boltzmann equation for dark matter-baryon scattering
• N-body simulations of dark matter-baryon interactions
• Non-Thermal Production of Sexaquark Dark Matter