We present two large cosmological N-body simulations, called Horizon Run 2 (HR2) and Horizon
Run 3 (HR3), made using 60003 = 216 billions and 72103 = 374 billion particles, spanning a volume
of (7.200 h?1Gpc)3 and (10.815 h?1Gpc)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, up to
1.25 ≠ 1011h?1M⊥, allowing to resolve galaxy-size halos with mean particle separations of 1.2h?1Mpc
and 1.5h?1Mpc, respectively. We have measured the power spectrum, correlation function, mass func-
tion and basic halo properties with percent level accuracy, and verified that they correctly reproduce
the CDM theoretical expectations, in excellent agreement with linear perturbation theory. Our un-
precedentedly 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 connec-
tion 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/.
Keyword
cosmological parameters-cosmology; theory-large scale structure of the universe-galaxies; formation-methods; N-body simulations