## SMDPL

The Small MultiDark Planck simulation belongs to the series of MultiDark simulations with Planck cosmology. Its simulation box has a side length of only 400 Mpc/h, less than half of the MDPL-size. With 3840^3 particles inside this small box it achieves a mass resolution of 10^{8} M_{sun}/h per dark matter particle.

Some more details for this simulation are described in Klypin et al. 2014.

Please cite this data set using the unique digital object identifier doi:10.17876/cosmosim/smdpl/.

Please give proper Credits when using data from this simulation.

### Details

Box size | 400 Mpc/h | side length of the cosmological cube |

Number of particles | 3840^{3} |
total number of dark matter particles |

Mass resolution | 9.63*10^{7} M_{sun}/h |
mass of one dark matter particle |

Force resolution | 1.5 kpc/h | physical force resolution |

Initial redshift | 120 | redshift at which the simulation started |

Cosmology | ||

h | 0.6777 | Hubble parameter |

Ω_{Λ} |
0.692885 | density parameter for dark energy |

Ω_{m} |
0.307115 | density parameter for matter (dark matter+baryons) |

Ω_{b} |
0.048206 | density parameter for baryonic matter |

n | 0.96 | normalization of the Power spectrum |

σ_{8} |
0.8228 | amplitude of mass density fluctuation in 8 Mpc/h sphere (at redshift z=0) |

Other constants | ||

G | 6.67428 * 10^{-8} cm^{3} g^{-1} s^{-2} |
Gravitational constant (Rev. Mod. Phys. 80 (2008) 633-730) |

1 Mpc | 30.85677 * 10^{23} cm |
1 Mpc in cm |

M_{sun} |
1.98892 ± 0.00025 10^{33} g |
Solar mass (Physics Reports 281 (1997) 309) |

### SMDPL 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 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 |
---|---|---|

AvailHalos | AvailHalos | Gives an overview on the snapshots, for which halo data are stored in the halo catalogues tables. In particular, it gives the number of halos/FOF groups for each snapshot. |

Dens512_z0 | Dens | Gives the cloud-in-cell smoothed densities for a 512^3 grid for redshift z = 0 (snapshot number 87, = 88) |

FOF | FOF | Main Friends-of-Friends catalogue for all available snapshots, level 0. Similar to the MDPL simulation, a relative linking length of 0.20 was used (like in MDR1.FOFc table).`fofId = (snapnum*10+level)*10` |

FOF1 FOF2 FOF3 FOF4 |
FOF | Friends-of-Friends catalogue for all available snapshots, same as FOF-table, but for smaller (relative) linking lengths (factor 2 for each step), levels 1 (linking length 0.10) to 5 (linking length 0.00625). 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) |

Redshifts | Redshifts | Overview on snapshot numbers (snapnum) and corresponding redshifts. In addition to the usual Redshifts-table columns, for SMDPL this table also contains a column `orig_snapnum` , which refers to the original snapshot number of the files. This differs from `snapnum` , because the simulation was run twice, first with more outputs at later times and second with more outputs at early times. |

Rockstar | Rockstar | ROCKSTAR halo catalogue with consistent merger trees for all available snapshots. |