I am interested in looking at the gas fractions and comparing them to the number of mergers for a specific cluster at different snapshots in the simulation. I have seen examples of how to do this with the raw snapshot downloads, but not with the API. How can I find the number of mergers for a cluster with the API? Please advise.
Under the documentation of the API you will find sublink/simple.json which returns a list of mergers for a given subhalo. This would be one option.
Alternatively, you can download the tree of the specific cluster you are looking at, then adapt the illustris_python.sublink.numMergers() function to your needs.