## Bolshoi

The Bolshoi simulation (from Russian “big”) has a simulation volume of (250 Mpc/h) ^{3} and a mass resolution of 1.35 * 10^{8} M_{sun}/h, which is more than a factor of 6 better than the mass resolution of the Millennium simulation. Its details are described in Klypin, Trujillo-Gomez & Primack 2010, some more information and images can be found at the Bolshoi simulation homepage. The main properties and cosmological parameters are listed in the table below; it uses the same WMAP5 cosmology as the MultiDark simulation MDR1, also see Simulations for an overview of all available and planned cosmological simulations.

Please give proper Credits when using data from this simulation.

### Details

Box size | 250 Mpc/h | side length of the cosmological cube |

Number of particles | 2048^{3 } |
total number of dark matter particles |

Mass resolution | 1.35 * 10^{8} M_{sun}/h |
mass of one dark matter particle |

Force resolution | 1.0 kpc/h | physical force resolution |

Initial redshift | 80 | redshift at which the simulation started |

Cosmology | ||

h | 0.70 | Hubble parameter |

Ω_{Λ} |
0.73 | density parameter for dark energy |

Ω_{m} |
0.27 | density parameter for matter (dark matter+baryons) |

Ω_{b} |
0.0469 | density parameter for baryonic matter |

n | 0.95 | normalization of the Power spectrum |

σ_{8} |
0.82 | amplitude of mass density fluctuation in 8 Mpc/h sphere (at redshift z=0) |

### Bolshoi data in the database

The following table provides an overview on the database tables which are available for this simulation. For each table, a link to its “table type” is given, which leads to a page explaining the individual columns of the corresponding table in more detail.

Several tables may contain a Peano-Hilbert key (phkey) for each row, which can be constructed from the position using the hilbert key function. If not indicated otherwise, the hilbert order for this simulation is 10, i.e. there are 2^{10} = 1024 cells per dimension.

Database table | Table type | Short description |
---|---|---|

BDMV | BDM | BDM (Bound Density Maximum) catalogue for all available snapshots, calculated using the standard overdensity criterion with 360*ρ (background density)._{back}`bdmId = ( snapnum*10` |

BDMVProf | BDMProf | Halo profiles of the BDMV catalogue for all available snapshots, calculated using the standard overdensity criterion with 360*ρ (background density)._{back} |

BDMW | BDM | BDM catalogue for all available snapshots, calculated using 200*ρ (critical density) for defining the halo boundary._{crit} |

BDMWProf | BDMProf | Halo profiles of the BDMW catalogue for all available snapshots, calculated using 200*ρ (critical density) for defining the halo boundary._{crit} |

Dens256_z0 | Dens | Density field for redshift 0, for 256^{3} grid cells; strongly smoothed |

Dens256 | Dens | Density fields for a number of snapshot numbers (see Redshifts-table or check with `SELECT DISTINCT snapnum FROM Bolshoi.Dens256` ), for 256^{3} grid cells; less strongly smoothed than for Dens256_z0. |

Dens512 | Dens | Density field for redshift 0, for 512^{3} grid cells |

FOF | FOF | Main Friends-of-Friends catalogue for all available snapshots, level 0 (relative linking length 0.17);`fofId = (snapnum*10 + level)*10` |

FOF1-FOF5 | FOF | Friends-of-Friends catalogue for all available snapshots, same as FOF-table, but for smaller (relative) linking lengths, levels 1 (linking length 0.085) to 4 (linking length 0.010625). Thus these tables contain substructures of the FOF groups. |

LinkLength | LinkLength | Overview on levels for FOF groups and corresponding linking lengths (for FOF, FOF1 – FOF4 tables) |

LinkLengthScl | LinkLength | Overview on sclevels for superclusters and corresponding linking lengths (for FOFScl table) |

Particles### | Particles | All simulation particles for snapshots (snapnum denoted by ###) with their positions and velocities.Currently, only snapshot 416 (redshift z=0) is available. |

Redshifts | Redshifts | Overview on snapshot numbers (snapnum) and corresponding redshifts |

Tweb256 | Web | Eigenvectors and eigenvalues of the gravitational tidal tensor, for a 256^{3} grid |

Tweb512 | Web | Eigenvectors and eigenvalues of the gravitational tidal tensor, for a 512^{3} grid |

Vweb256 | Web | Eigenvectors and eigenvalues of the velocity shear tensor, for a 256^{3} grid |

Vweb512 | Web | Eigenvectors and eigenvalues of the velocity shear tensor, for a 512^{3} grid |