Hi, I appreciate that I can use this galaxy simulation and the API about halo.
I have some questions that I would like to have answered.
How to get halo_id in Browsable REST API?
I want to try to get the ids of all halo's (not subhalo's).
From there, I can determine if this halo is in a specific quality range.
They exist in a single specific page (similar to https://www.tng-project.org/api/Illustris-2/snapshots/135/halos/10/)
But there is no page like https://www.tng-project.org/api/Illustris-2/snapshots/135/halos/ (which shows that the page does not exist) that shows all halo_id's.
Is there any good way to count them?
Looking forward to hearing back from you.
Translated with www.DeepL.com/Translator (free version)
If you want to search by halo properties, e.g. m200 or rvir, then you should use the group catalog. You can either download it for a given snapshot (not too large, few GB), or else use the Lab service.
Thank you very much for your assistance, I have successfully categorized the halo through catalog.
But I have a question, why groupcat is saving the data of halo by segmentation? And what is the basis for dividing a groupcat into multiple hdf5 to save?
hope you can answer my question.
This is just to have smaller, more manageable files for e.g. downloading.
One could combine the entire catalog into a single file if you wanted, the information would be the same.
Thank you very much!
This is a question about halo and subhalo.
For example, in the simulation of illustris3, why is the halo with infoID = 0 in the same spatial position (with the same pos) as the subhalo with id = 0 does it mean they are the same?
But again their quality is totally different, why is that?
I would suggest perhaps to read the Subfind paper (Section 4), for another description of halos and subhalos, in addition to the documentation for IllustrisTNG in particular.