Why "SubhaloID" is not in the group catalog?

Suin Matsui
  • 3 Jul

I am using the supplementary catalog: (t) Galaxy Morphologies (Kinematic) and Bar Properties.
This catalog contains only "SubhaloID" information.
However, the group catalog does not have a "SubhaloID" entry; it only includes "SubfindID" information.
Due to this discrepancy, I am having trouble linking the two catalogs together.

I have referred to past consultations on the TNG project forum, specifically this thread: https://www.tng-project.org/data/forum/topic/613/merger-tree-subhaloid/.

Can I use the formula "10000000000000000 * snapshot_number + sub_index" to convert SubhaloID back to SubfindID?

Suin Matsui
  • 7 Jul

Sorry, I have resolved this myself.

Using the merger tree, I found that the "SubhaloID" from the group catalog does not match the "SubhaloID" from the supplementary catalog (t).

Therefore, the SubhaloID in the supplementary catalog (t) is actually the SubfindID.

Dylan Nelson
  • 9 Jul

Yes that's correct, the SubhaloID in the SubLink merger trees is internal, and only used within the merger tree.

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