MDR1

Slice of MDR1 at redshift z = 0.53. More images

MDR1 is the first MultiDark simulation, performed in 2010. A detailed description is available in the paper Prada et al. 2011, arXiv:1104.5130. This simulation contains about 8.6 billion particles in a (1 Gpc/h)3 cube and thus has a larger volume than the Millennium Simulation, using the more up-to-date WMAP5 cosmology.

Also see Simulations overview for an overview of all available and planned cosmological simulations.

Please give proper Credits when using data from this simulation.

Details

Box size 1 Gpc/h side length of the cosmological cube
Number of particles 20483 total number of dark matter particles
Mass resolution 8.721*109 Msun/h mass of one dark matter particle
Force resolution 7 kpc/h physical force resolution
Initial redshift 65 redshift at which the simulation started
Cosmology
h 0.70 Hubble parameter
ΩΛ 0.73 density parameter for dark energy
Ωm 0.27 density parameter for matter (dark matter+baryons)
Ωb 0.0469 density parameter for baryonic matter
n 0.95 normalization of the Power spectrum
σ8 0.82 amplitude of mass density fluctuation in 8 Mpc/h sphere (at redshift z=0)
Other constants
G 6.67428 * 10-8 cm3 g-1 s-2 Gravitational constant (Rev. Mod. Phys. 80 (2008) 633-730)
1 Mpc 30.85677 * 1023 cm 1 Mpc in cm
Msun 1.98892 ± 0.00025 1033 g Solar mass (Physics Reports 281 (1997) 309)

MDR1 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 (halo catalogues, particle tables) contain a Peano-Hilbert key 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 210 = 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 FOF or BDM tables.
AvailParticles AvailParticles Gives an overview for which snapshots there are raw particle data available.
BDMV BDM BDM (Bound Density Maximum) catalogue for all available snapshots, calculated using the standard overdensity criterion with 360*ρback (background density).
bdmId = ( snapnum*108 +(number in BDM catalogue) )
BDMVProf BDMProf Halo profiles of the BDMV catalogue for all available snapshots, calculated using the standard overdensity criterion with 360*ρback (background density).
BDMW BDM BDM catalogue for all available snapshots, calculated using 200*ρcrit (critical density) for defining the halo boundary.
bdmId = ( snapnum*108 +(number in BDM catalogue) )
BDMWProf BDMProf Halo profiles of the BDMW catalogue for all available snapshots, calculated using the standard overdensity criterion with 360*ρback (background density).
BDMWMfreq Mfreq Galaxy cluster catalogue for distinct halos from the BDMW catalogue with a total mass (Mtot) above 1014 Msun/h, only for snapshots corresponding to the redshift values z = 0, 0.05, 0.1, 0.16, 0.18, 0.2, 0.27, 0.32, 0.37, 0.4, 0.47, 0.53, 0.61, 0.69, 0.78, 0.89 and 1.
Dens512_z0 Dens Density field for redshift 0, for 5123 grid cells
Dens1024_z0 Dens Density field for redshift 0, for 10243 grid cells
FOF FOF Main Friends-of-Friends catalogue for all available snapshots, level 0 (relative linking length 0.17);
fofId = (snapnum*10 + level)*108 +(rank in FOF-file)
FOF1-FOF4 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.
FOFc FOF Friends-of-Friends catalogue for all available snapshots, computed with the commonly used linking length 0.2, as was used first by White et al. 1987. The corresponding average overdensity with this value is about 400 – contrary to the popular belief of 200 (see More et al. 2011. The level-column is replaced here by a linkLength_rel column, which provides the used linking length directly.
FOFMtree FOFMtree Merger trees for top level FOF groups (level=0) with > 2 * 1012 Msun/h from redshift 0. Substructures are not taken into account.
FOFParticles FOFParticles Table for connecting FOF groups from the FOF table with its particles, at the moment for redshift 0 (snapnum=85) only.
FOFParticles1 – FOFParticles4 FOFParticles Corresponding tables for connecting FOF groups from tables FOF1 – FOF4 to their particles for redshift 0.
FOFParticles## FOFParticles Corresponding tables for connecting FOF groups from the main FOF table with their particles## for redshift ##.
FOFScl FOFsub FOF superclusters; contains Friends-of-Friends catalogues for redshift 0, for 7 different (relative) linking lengths between 0.35 (sclevel 0) and 0.17 (sclevel 6)), i.e. much larger objects (superclusters) than in the FOF table. It also contains identifiers for building substructure trees
FOFSclParticles_85_l0 – …l6 FOFParticles Table for connecting FOF groups from the FOFScl superclusters table with its particles; the number at the end indicates the level of substructure
FOFSub FOFsub FOF substructure tree connecting the FOF – FOF4 catalogues at snapnum=85 (z=0).
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## Particles All simulation particles for various snapshots (denoted by ##) with their positions and velocities.
A list of all available snapshots can be obtained from table AvailParticles.
Redshifts Redshifts Overview on snapshot numbers (snapnum) and corresponding redshifts
Rockstar Rockstar Consistent halo catalogue with merger trees
TreeSnapnums TreeSnapnums Maps between snapshot numbers used in the FOF merger trees for MDR1 and the “usual” snapshot numbers.
Tweb512 Web Eigenvectors and eigenvalues of the gravitational tidal tensor, for a 5123 grid
Tweb1024 Web Eigenvectors and eigenvalues of the gravitational tidal tensor, for a 10243 grid
Vweb512 Web Eigenvectors and eigenvalues of the velocity shear tensor, for a 5123 grid
Vweb1024 Web Eigenvectors and eigenvalues of the velocity shear tensor, for a 10243 grid

 

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