Scientific Purpose
Horizon Run 5 (HR5) is a cosmological hydrodynamical simulation which captures the properties of the Universe on a $\mathrm{Gpc}$ scale while achieving a resolution of 1 $\mathrm{kpc}$. This enormous dynamic range allows us to simultaneously capture the physics of the cosmic web on very large scales and account for the formation and evolution of dwarf galaxies on much smaller scales. Inside the simulation box, we zoom-in on a high-resolution cuboid region with a volume of 1049$\times$119$\times$127 $\mathrm{cMpc}^3$. The sub-grid physics chosen to model galaxy formation includes radiative heating/cooling, reionization, star formation, supernova feedback, chemical evolution tracking the enrichment of oxygen and iron, the growth of supermassive black holes and feedback from active galactic nuclei (AGN) in the form of a dual jet-heating mode. For this simulation, we implemented a hybrid MPI-OpenMP version of the RAMSES code, specifically targeted for modern many-core many thread parallel architectures. Light cone space data was generated on-the-fly, as well as snapshots. For the post-processing, we extended the Friends-of-Friend (FoF) algorithm and developed a new galaxy finder PGalF to analyze the large outputs of HR5. The simulation successfully reproduces observations, such as the cosmic star formation history and connectivity of galaxy distribution. HR5 contains cosmological structures in a wide range of scales, from filaments of a few $\mathrm{cMpc}$ lengths to voids of $\sim\,$100 $\mathrm{cMpc}$ radii. The simulation also indicates that hydrodynamical effects on small scales impact galaxy clustering up to very large scales near and beyond the baryonic acoustic oscillation (BAO) scale. Hence, caution should be taken when using that scale as a cosmic standard ruler: one needs to understand the corresponding biases carefully. The simulation is expected to be an invaluable asset for the interpretation of upcoming deep surveys of the Universe.
Authors
- Jaehyun Lee at Korea Institute for Advanced Study (KIAS)
- Yonghwi Kim at Korea Institute of Science and Technology Information (KISTI) / KIAS
- Changbom Park at KIAS
- Juhan Kim at CAC of KIAS
- Owain N. Snaith at GEPI, Observatoire de Paris
- Jihye Shin at Korea Astronomy and Space Science Institute (KASI)
- Sungwook E. Hong at KASI
- Oh-Kyoung Kwon at KISTI
- Chan Park at Instite for Basic Science
- Yohan Dubois at Institut d'Astrophysique de Paris (IAP)
- Christophe Pichon at IAP / KIAS
- C. Gareth Few at University of Hull and Durham University
- Leah M. Cox at Univerity of Hull
- Brad K. Gibson at University of Hull
- Julien Devriendt at University of Oxford
Cosmological model of the Horizon Run 5
All the HR's share the same cosmology, but the HR5 reflects recent updates of the Planck observation.
Cosmological parameters of the HR's
| Cosmological model | $\Omega_{m,0}$ | $\Omega_{b,0}$ | $\Omega_{\Lambda,0}$ | $n_\mathrm{s}$ | $H_0$ (km/s/Mpc) | $\sigma_8$ |
|---|---|---|---|---|---|---|
| $\Lambda$CDM Planck | 0.3 | 0.047 | 0.7 | - | 68.4 | 1/1.225 |
| Simulations Name | HR1 | HR2 | HR3 | HR4 | HR5 |
|---|---|---|---|---|---|
| Box Size ($c\mathrm{Mpc}$) | 9417 | 10285 | 15450 | 4436 | 1049 |
| Number of CDM particles | 4120$^3$ | 6000$^3$ | 7210$^3$ | 6300$^3$ | gas cells + particles |
| Starting redshift | 23 | 32 | 27 | 100 | 200 |
| Initial power spectrum generator | Eisenstein & Hu (1998) | CAMB Source | CAMB Source | CAMB Source | CAMB Source |
| Initial displacement | Zel'dovich | Zel'dovich | Zel'dovich | 2LPT | 2LPT |
| Code | GOTPM (Dubinski, Kim, Park 2004) | GOTPM | GOTPM | GOTPM | RAMSES (Teyssier 2002) |
Outputs from the simulation
- 171 snapshot data from z=200 to z=0.625
- Halo, subhalo, and galaxy data using PGalF (PSB-based Galaxy Finder, Kim et al. in prep.)
- 5 dense regions with finer time steps with selecting cluster candidate haloes (Log$M_{200}/M_{\odot}$$\sim$14.7-15.0 at z=0) from a low resolution simulation based on the same IC
- All-sky past lightcone data from 2 mock observers out to z=0.625