I was wondering if there was any way to access the positions and velocities of subhalos in a subbox's snapshot? I know that for fullbox snapshots that this information is accessed through the group catalogues, but the group catalogues do not exist for the subbox. I was wondering if there was a supplementary catalogue that might contain the data I am searching for?
The "Subbox Subhalo List" supplementary data catalog is the most useful (only) dataset of relevance here. It can help locate subhalos in the subboxes, and including positions, though does not include velocities. You could compute velocities by interpolating between the neighboring full snapshot group catalogs.