I am trying to get Bound Remnant of MW/M31-like Satellites at z=0 from the "TNG50 MW/M31-like Satellites catalog", but I couldn't do it.
My goal is to get (a) the whole mass of each satellite at infall, (b) how they lost mass with time/redshift after each orbit due to tidal stripping, and (b) their current mass (z=0), which I have already got from the Catalog.
At the end, my target is to define a function of (Mass_present/Mass_infall).
Can you please tell me how I will get those info from the Data?
If you have the z=0 subhalo IDs of your satellites of interest, you would want to load their merger trees. All you need are the "main progenitor branches".
This will give you t, xyz(t), mass(t) where t is really snapshot number, you can convert it to redshift or e.g. lookback time.
t, xyz(t), mass(t)
You would want to compare xyz(t) versus the position of the host halo with time, you can similarly load its MPB to get that information.
If you want to define infall as the crossing of r200c (for example), then you should be able to identify when this occurs for each satellite, and then find its infall mass at that snapshot.