3.3.3  :  MMSnapshots

This database contains tables with the original dark matter particles from the milli-Millennium simulation. There is also a table linking the particles to particular FOF groups and/or sub-halos they belong to.

This database also contains a number of so called User Defined Functions (UDF-s) that can be used to efficiently create spatial subsets of the particle distribution. To call a function you should add the "dbo." schema name in front of the function name. And the databas ename itself should also be included.

  • select *
      from mmsnapshots.dbo.mmsnapshotpointsinbox(snapnum,xmin,ymin,zmin,xmax,ymax,zmax)
    
  • returns a table with particles [x,y,z,vx,vy,vz,id] in the box given by the xmin..zmax parameters at the given snapnum. (Of course numerical values should be substituted for the parameters). This function takes periodicity of the simulation box into account. I.e. the box may cross the boundary of the box.
  • select *
      from mmsnapshots.dbo.mmsnapshotpointsinsphere(snapnum,x,y,z,radius)
    
  • returns a table with particles [r,x,y,z,vx,vy,vz,id] in the sphere given by the center and radius at the given snapnum. This function takes periodicity of the simulation box into account. I.e. the sphere may cross the boundary of the box. The r column gives the distance to the center of the sphere.