# Available Data

## Particle Data

The core N-body code used to run Caterpillar was a combination of `P-Gadget3` and `Gadget-4`.  The output of the simulation runs is the typical Gadget HDF5 output and should be compatible with all other downstream post-processing tools available in the community. These outputs are available at all 320 snapshots of the simulation from z = 127 to z = 0 with < 50 Myr resolution from z = 6 to z = 0.

For details, please see either our flagship paper or our Technical pages.

{% hint style="info" %}
Owing to the extreme size of the runs, particle data (z > 0) is only available upon request.
{% endhint %}

## Halo Catalogues

{% tabs %}
{% tab title="Rockstar" %}
We used a modified version of `ROCKSTAR` included full iterative unbinding but the outputs are consistent with the nominal outputs from standard `ROCKSTAR` catalogues. Please see the documentation at the [Rockstar repository](https://bitbucket.org/gfcstanford/rockstar/src/master/README.md) for details (See [Section 4. Outputs](https://bitbucket.org/gfcstanford/rockstar/src/master/README.md#markdown-header-output)). There are however a few important caveats relating to our outputs which differ from the nominal outputs.

e.g. M\_grav vs. Mvir vs npart\*m\_p
{% endtab %}

{% tab title="SUBFIND" %}
These can be made available upon request.
{% endtab %}
{% endtabs %}

## Merger Trees

The chosen merger tree system used is [consistent-trees](https://bitbucket.org/pbehroozi/consistent-trees/src/master/). Please see the `consistent-trees` [README](https://bitbucket.org/pbehroozi/consistent-trees/src/master/README.md) for direct information pertaining to its running and output.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.caterpillarproject.org/data.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.