3.3.10.2  :  Subhalo

This table contains the SubFind group catalogues for all 64 snapshots of the Millennium Run (MR). The FoF groups which contain these subhalos are listed in the FoF table.

columntypeUCDunitdescription
SubhaloID long meta.id;meta.main The ID of this subhalo, unique within the full simulation.
FoFID long meta.id.assoc The unique ID of the FoF group this subhalo belongs to.
sublen int meta.number The number of simulation particles in this SubFind group.
isCentre char(1) T if this is the most massive subhalo in the FoF group, F otherwise.
SnapNum int time The snapshot number where this subhalo was identified.
Redshift float time The redshift of the snapshot to which this subhalo belongs.
x float pos.cartesian.x 1/h Mpc x-component position
y float pos.cartesian.y 1/h Mpc y-component position
z float pos.cartesian.z 1/h Mpc z-component position
velx float phys.veloc km/s x-component of peculiar velocity
vely float phys.veloc km/s y-component of peculiar velocity
velz float phys.veloc km/s z-component of peculiar velocity
phKey integer Peano-Hilbert key, (bits=8), for position in 500/h Mpc box. See the text on spatial indexes.
zIndex integer The "bit-interleaved" or "Z-curve" index, corresponding to this halo's position. Same resolution as phKey. See the text on spatial indexes.
ix integer pos.cartesian.x Zone index along x-direction, based on 50 bins. See the text on spatial indexes.
iy integer pos.cartesian.y Zone index along y-direction, based on 50 bins. See the text on spatial indexes.
iz integer pos.cartesian.y Zone index along z-direction, based on 50 bins. See the text on spatial indexes.
velDisp float phys.veloc.dispersion km/sec he velocity dispersion of the halo.
vMax float phys.veloc.rotat km/sec Maximum rotational velocity, calculates as the maximum of the expression sqrt(G M(r)/r) where r runs of the particles in the halo.
spinX float phys.veloc.ang (Mpc/h) (km/sec) The X-component of the spin of the halo.
spinY float phys.veloc.ang (Mpc/h) (km/sec) The Y-component of the spin of the halo.
spinZ float phys.veloc.ang (Mpc/h) (km/sec) The Z-component of the spin of the halo.
mostBoundID long meta.id.assoc The id of the most bound particle of this halo.
fileNr int meta.file;meta.id Original file number in which the subhalo was defined.
subhaloIndex int meta.id.assoc Index of this subhalo in the file identified by fileNr.
halfmassRadius float phys.size.radius Mpc/h Radius containing half of the mass of the halo.
random float A random number between 0 and 1000000. See the section on random sampling.