The New Horizon Run Cosmological N-Body Simulations

TL;DR

The Horizon Run simulations are large-scale cosmological N-body simulations that provide detailed insights into structure formation, dark energy, and galaxy evolution, with high accuracy and publicly available mock surveys for the scientific community.

Contribution

We present two unprecedented large-volume, high-resolution cosmological N-body simulations, significantly surpassing previous simulations in volume and resolution, and provide extensive mock surveys for cosmological studies.

Findings

Power spectrum and correlation function match LCDM predictions.

Simulations accurately reproduce halo mass functions.

Mock surveys facilitate studies of large-scale structure and galaxy formation.

Abstract

We present two large cosmological N-body simulations, called Horizon Run 2 (HR2) and Horizon Run 3 (HR3), made using 6000^3 = 216 billions and 7210^3 = 374 billion particles, spanning a volume of (7.200 Gpc/h)^3 and (10.815 Gpc/h)^3, respectively. These simulations improve on our previous Horizon Run 1 (HR1) up to a factor of 4.4 in volume, and range from 2600 to over 8800 times the volume of the Millennium Run. In addition, they achieve a considerably finer mass resolution, down to 1.25x10^11 M_sun/h, allowing to resolve galaxy-size halos with mean particle separations of 1.2 Mpc/h and 1.5 Mpc/h, respectively. We have measured the power spectrum, correlation function, mass function and basic halo properties with percent level accuracy, and verified that they correctly reproduce the LCDM theoretical expectations, in excellent agreement with linear perturbation theory. Our unprecedentedly large-volume N-body simulations can be used for a variety of studies in cosmology and astrophysics, ranging from large-scale structure topology, baryon acoustic oscillations, dark energy and the characterization of the expansion history of the Universe, till galaxy formation science - in connection with the new SDSS-III. To this end, we made a total of 35 all-sky mock surveys along the past light cone out to z=0.7 (8 from the HR2 and 27 from the HR3), to simulate the BOSS geometry. The simulations and mock surveys are already publicly available at http://astro.kias.re.kr/Horizon-Run23/.