The Bulletin of The Korean Astronomical Society (천문학회보)

The Korean Astronomical Society (한국천문학회)
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The Horizon Run 5 Cosmological Hydrodynamical Simulation: Probing Galaxy Formation from Kilo- to Giga-parsec Scales

  • Lee, Jaehyun (Korea Institute for Advanced Study) ;
  • Shin, Jihey (Korea Astronomy and Space Science Institute) ;
  • Snaith, Owain N. (Observatoire de Paris) ;
  • Kim, Yonghwi (Korea Institute for Advanced Study) ;
  • Few, C. Gareth (University of Hull) ;
  • Devriendt, Julien (University of Oxford) ;
  • Dubois, Yohan (CNRS and Sorbonne Universite) ;
  • Cox, Leah M. (University of Hull) ;
  • Hong, Sungwook E. (University of Seoul) ;
  • Kwon, Oh-Kyoung (Korea Institute of Science and Technology Information) ;
  • Park, Chan (National Institute for Mathematical Science) ;
  • Pichon, Christophe (Korea Institute for Advanced Study) ;
  • Kim, Juhan (Korea Institute for Advanced Study) ;
  • Gibson, Brad K. (University of Hull) ;
  • Park, Changbom (Korea Institute for Advanced Study)
  • Published : 2020.10.13
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Abstract

Horizon Run 5 (HR5) is a cosmological hydrodynamical simulation which captures the properties of the Universe on a Gpc scale while achieving a resolution of 1 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 × 114 × 114 Mpc3. The subgrid 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. For the post-processing, we extended the Friends-of-Friend (FoF) algorithm and developed a new galaxy finder to analyse the large outputs of HR5. The simulation successfully reproduces many observations, such as the cosmic star formation history, connectivity of galaxy distribution and stellar mass functions. 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 carefully understand the corresponding biases. The simulation is expected to be an invaluable asset for the interpretation of upcoming deep surveys of the Universe.

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