3.3.9.4  :  DHalo

This table contains the catalogue of halos used to construct the merger trees used in the DGalaxies..Bower2006a and DGalaxies..Font2008a galaxy catalogues. Each DHalo is a collection of SubFind subhalos grouped together to make a halo. Note that the objects referred to as subhalos here (SubFind groups) are equivalent to the objects listed in the MHalo table.

columntypeUCDunitdescription
DHaloID long meta.id;meta.main The ID of this DHalo, unique within the full simulation.
DescendantId long meta.id.assoc The ID of the descendant of this DHalo in the merger tree.
LastProgenitorId long meta.id.assoc Indicator of the last progenitor in the DHalo merger tree rooted in this DHalo.
All DHalos with id between ID and LastProgenitorId form the merger tree rooted in this DHalo.
TreeId long meta.id.parent The unique id of the DHalo merger tree to which this DHalo belongs.
FirstSubhaloID long meta.id.assoc The unique id of the most massive subhalo in this DHalo
np int meta.number Number of simulation particles in this DHalo. This is equal to the total number of particles in the constituent subhalos of the DHalo.
NSubhalos int meta.number Number of subhalos in this DHalo.
SnapNum int time The snapshot number where this DHalo was identified.
Redshift float time The redshift of the snapshot to which this DHalo belongs.
FirstProgenitorID long meta.id.assoc The ID of the most massive progenitor of the DHalo
EndMainBranchID long meta.id.assoc The ID of the halo at the end of the main progenitor branch of this halo.
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.
random float A random number between 0 and 1000000. See the section on random sampling.