I am trying to extract data for the secondary cluster in a merger using the Cluster Mergers catalog.
The catalog provides a SubclusterID (in my case, 401471252), and I initially assumed this corresponds directly to a Subhalo ID. Based on that, I attempted using SubhaloGrNr from the Group Catalog to retrieve the parent halo (cluster) ID. However, it returns that "Index 401471252 is out of bounds for axis 0 with size 10378451".
Then, I tried using Sublink Trees with il.sublink.loadTree(basePath, 89, 401471252, onlyMPB=True). But again, "Index (401471252) out of range for (0-11017171)".
This makes me unsure about the exact meaning of SubclusterID.
My questions are:
What does the SubclusterID field represent in the Cluster Mergers catalog?
How can I correctly retrieve the data (e.g., Subhalo or Group properties) for the secondary cluster involved in a merger?
Any clarification or example workflow would be greatly appreciated.
Wonki Lee
15h
Hi,
The SubclusterID in the merger catalog is defined using the "SubhaloID" of SubLink, which is the unique ID stored internally in SubLink.
To retrieve the physical properties of a subcluster involved in a merger, you need to use sublink.loadTree. Specifically: i) if the subcluster has fully merged into the main cluster, you can find it by matching its SubhaloID within the tree loaded for the main cluster; or ii) if the subcluster is still undergoing collision at z=0, it can be identified in its own separate SubLink tree, where its SubhaloID will match the SubclusterID stored in the catalog.
I am trying to extract data for the secondary cluster in a merger using the Cluster Mergers catalog.
The catalog provides a SubclusterID (in my case, 401471252), and I initially assumed this corresponds directly to a Subhalo ID. Based on that, I attempted using SubhaloGrNr from the Group Catalog to retrieve the parent halo (cluster) ID. However, it returns that "Index 401471252 is out of bounds for axis 0 with size 10378451".
Then, I tried using Sublink Trees with il.sublink.loadTree(basePath, 89, 401471252, onlyMPB=True). But again, "Index (401471252) out of range for (0-11017171)".
This makes me unsure about the exact meaning of SubclusterID.
My questions are:
What does the SubclusterID field represent in the Cluster Mergers catalog?
How can I correctly retrieve the data (e.g., Subhalo or Group properties) for the secondary cluster involved in a merger?
Any clarification or example workflow would be greatly appreciated.
Hi,
The SubclusterID in the merger catalog is defined using the "SubhaloID" of SubLink, which is the unique ID stored internally in SubLink.
To retrieve the physical properties of a subcluster involved in a merger, you need to use sublink.loadTree. Specifically: i) if the subcluster has fully merged into the main cluster, you can find it by matching its SubhaloID within the tree loaded for the main cluster; or ii) if the subcluster is still undergoing collision at z=0, it can be identified in its own separate SubLink tree, where its SubhaloID will match the SubclusterID stored in the catalog.