Numerical Discreteness Errors in Multi-Species Cosmological N-body Simulations
arXiv:2303.00639 · doi:10.1093/mnras/stad1176
Abstract
We present a detailed analysis of numerical discreteness errors in two-species, gravity-only, cosmological simulations using the density power spectrum as a diagnostic probe. In a simple setup where both species are initialized with the same total matter transfer function, biased growth of power forms on small scales when the solver force resolution is finer than the mean interparticle separation. The artificial bias is more severe when individual density and velocity transfer functions are applied. In particular, significant large-scale offsets in power are measured between simulations with conventional offset grid initial conditions when compared against converged high-resolution results where the force resolution scale is matched to the interparticle separation. These offsets persist even when the cosmology is chosen so that the two particle species have the same mass, indicating that the error is sourced from discreteness in the total matter field as opposed to unequal particle mass. We further investigate two mitigation strategies to address discreteness errors: the frozen potential method and softened interspecies short-range forces. The former evolves particles under the approximately "frozen" total matter potential in linear theory at early times, while the latter filters cross-species gravitational interactions on small scales in low density regions. By modeling closer to the continuum limit, both mitigation strategies demonstrate considerable reductions in large-scale power spectrum offsets.
arXiv commentAccepted for publication in MNRAS
References in corpus (40)
- Efficient Computation of CMB anisotropies in closed FRW models
- The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
- LSST: from Science Drivers to Reference Design and Anticipated Data Products
- Properties of galaxies reproduced by a hydrodynamic simulation
- FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation
- Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report
- The Inner Structure of LambdaCDM Halos I: A Numerical Convergence Study
- The BAHAMAS project: Calibrated hydrodynamical simulations for large-scale structure cosmology
- The Coyote Universe I: Precision Determination of the Nonlinear Matter Power Spectrum
- Discreteness effects in simulations of Hot/Warm dark matter
- HACC: Simulating Sky Surveys on State-of-the-Art Supercomputing Architectures
- Matter power spectrum and the challenge of percent accuracy
- The Zeldovich approximation
- Robustness of Cosmological Simulations I: Large Scale Structure
- Two body relaxation in CDM simulations
- Two--body heating in numerical galaxy formation experiments
- Fundamental Discreteness Limitations of Cosmological N-Body Clustering Simulations
- Accurate initial conditions for cosmological N-body simulations: Minimizing truncation and discreteness errors
- Energy equipartition between stellar and dark matter particles in cosmological simulations results in spurious growth of galaxy sizes
- The imprint of neutrinos on clustering in redshift-space
- The formation of the first cosmic structures and the physics of the z~20 Universe
- An adaptively refined phase-space element method for cosmological simulations and collisionless dynamics
- Discreteness Effects in Lambda Cold Dark Matter Simulations: A Wavelet-Statistical View
- On effects of resolution in dissipationless cosmological simulations
- Higher-order initial conditions for mixed baryon-CDM simulations
- Demonstrating Discreteness and Collision Error in Cosmological N-body Simulations of Dark Matter Gravitational Clustering
- How closely do baryons follow dark matter on large scales?
- Two-Body Relaxation in Cosmological Simulations
- Towards quantitative control on discreteness error in the non-linear regime of cosmological N body simulations
- Nonlinear evolution of density perturbations using approximate constancy of gravitational potential
- The Evolution of Baryon Density Fluctuations in Multi-Component Cosmological Simulations
- A fast recursive coordinate bisection tree for neighbour search and gravity
- Reliability of the dark matter clustering in cosmological N-body simulation on scales below the mean separation length of particles
- Galaxy Formation: Warm Dark Matter, Missing Satellites, and the Angular Momentum Problem
- More accurate simulations with separate initial conditions for baryons and dark matter
- Spurious Small-Scale Structure & Discreteness-Driven Relaxation in Cosmological Simulations
- Accurate initial conditions in mixed Dark Matter--Baryon simulations
- Formation and Evolution of Galaxies: Les Houches Lectures
- The Borg Cube Simulation: Cosmological Hydrodynamics with CRK-SPH
- Gravitational collapse in an expanding background and the role of substructure II: Excess power at small scales and its effect of collapse of structures at larger scales