EUNHA: a new cosmological hydro simulation code

TL;DR

EUNHA is a newly developed parallel cosmological hydrodynamics simulation code that models structure formation, incorporating gravity, gas physics, star formation, and feedback, validated through standard tests and galaxy evolution studies.

Contribution

The paper introduces EUNHA, a novel simulation code combining TreePM gravity, SPH hydrodynamics, and astrophysical processes for cosmological structure formation.

Findings

Successfully tested with standard hydrodynamic problems.

Reproduces the Schmidt-Kennicutt relation in galaxy simulations.

Global star formation histories align with observations.

Abstract

We have developed a parallel cosmological hydrodynamic simulation code designed for the study of formation and evolution of cosmological structures. The gravitational force is calculated using the TreePM method and the hydrodynamics is implemented based on the smoothed particle hydrodynamics. The initial displacement and velocity of simulation particles are calculated according to second-order linear perturbation theory using the power spectra of dark matter and baryonic matter. The initial background temperature is given by Recfast and the temperature uctuations at the initial particle position are determined by the adiabatic model. We use a time-limiter scheme over the individual time steps to capture shock-fronts and to ease the time-step tension between the shock and preshock particles. We also include the astrophysical gas processes of radiative heating/cooling, star formation, metal enrichment, and supernova feedback. We have tested the code in several standard cases such as one-dimensional Riemann problems, Kelvin-Helmholtz, and Sedov blast wave instability. Star formation on the galactic disk is investigated to check whether the Schmidt-Kennicutt relation is properly recovered. We also study global star formation histories at different simulation resolutions and compare them with observations.