TNG Subbox Question

Craig Cissel
  • 27 Jun '19

Questions about accessing the higher time resolution subboxs.

Are they located within the same data sets as the normal data? Is there anyway to just download all the snapshots of a subbox?

And are the ways to access the data parameteres in a subbox the same as the normal data?

Thanks you!

Dylan Nelson
  • 29 Jun '19

Hi Craig,

The subboxes are located -spatially- within the main boxes, this is correct. But, they are in separate files. So you can definitely download them separately (they are, on the main page, listed separately under "Subboxes").

Yes the same scripts and such should work on these snapshots, let us know if you run into any trouble.

Craig Cissel
  • 1 Jul '19

Thank you!

However I have run into a problem.

No matter what subbox I try to download, I run into an issue where wget can't find some of the urls.
Namely: "" or any of its"" counterparts.

Is there anything I can do to help this?


Dylan Nelson
  • 2 Jul '19

Hi Craig,

The actual data downloads on have unfortunately become a bit unreliable recently, I am going to change this soon.

In the meantime, please just switch to - you will find all the same original Illustris data also there, and things should work much better.

Craig Cissel
  • 9 Jul '19

I'm running into trouble accessing the subbox data. You said the same scripts should work on the new subbox data but I'm unsure if i'm doing this correctly. How should I go about loading the position and velocity values for all of the galaxies within the subbox at each snap? All of the files that were downloaded seemed to be prefaced with "snap_subbox1_groupNum.{N}" or "simulation". I temporarily amended the groupcat file to also load the 'snap_subbox1" files to the gcPath but none of the fields existed in those files, as far as I could tell. Did I not download all of the data available?

I'd ideally like to be able to follow select a few galaxies of interest throughout various timesteps in the subbox.

Thank you! and apologies for any of my ignorance on accessing this data. You have been an amazing help so far.

Dylan Nelson
  • 10 Jul '19


You should think of the subboxes as particle/cell dumps for that region of space. Unfortunately, there was no group finder run on these outputs, so there are no "group catalogs" or lists of subhalos.

A good option is to use the group catalogs from the main snapshots and a merger tree of an object which is moving through a subbox, to obtain e.g. its (approximate) position versus time. I have done such an exercise in general for the TNG runs and produced this Subbox Subhalo List supplementary data catalog, which might me of interest.

To actually load the subbox particle data with the scripts, you're right you might want to modify snapPath() to account for the different naming scheme.

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