Hi Nelson ~ i am a graduate student currently using TNG-300 to calculate the 2pcf for central galaxy sample and all (central + satellite) galaxy sample, but i have a question for the data. So in the Data Specifications, i use the GroupFirstSub to find which one is the central galaxy, but i am not sure how you define the central galaxy, as show in the specification: ' Index into the Subhalo table of the first (i.e. central/primary) Subfind subhalo within this FoF group. The subhalos of a group are ordered in descending total number of bound particles/cells. The first/central subhalo is usually, but not always, the most massive. Note: This value is signed (or should be interpreted as signed)! In this case, a value of -1 indicates that this FoF group has no subhalos. '
so does it means that we calculate the total number of DM particles, and we define that the subhalo with largest number of DM particles is the central subhalo? Wish you have a good day ~ looking forward to your reply ^ ^
Dylan Nelson
15 May
The assignment of central subhalo is made according to the Subfind algorithm.
The original algorithm description is given in Springel+01 (Section 4.2).
Hi Nelson ~ i am a graduate student currently using TNG-300 to calculate the 2pcf for central galaxy sample and all (central + satellite) galaxy sample, but i have a question for the data. So in the Data Specifications, i use the GroupFirstSub to find which one is the central galaxy, but i am not sure how you define the central galaxy, as show in the specification: ' Index into the Subhalo table of the first (i.e. central/primary) Subfind subhalo within this FoF group. The subhalos of a group are ordered in descending total number of bound particles/cells. The first/central subhalo is usually, but not always, the most massive. Note: This value is signed (or should be interpreted as signed)! In this case, a value of -1 indicates that this FoF group has no subhalos. '
so does it means that we calculate the total number of DM particles, and we define that the subhalo with largest number of DM particles is the central subhalo? Wish you have a good day ~ looking forward to your reply ^ ^
The assignment of central subhalo is made according to the Subfind algorithm.
The original algorithm description is given in Springel+01 (Section 4.2).
ok！ thanks a lot