Halotools

What it does

Analysis examples

The tutorials demonstrate galaxy clustering, galaxy-galaxy lensing, group identification, velocity statistics, void statistics, and isolation criteria.checked 4 Oct 2026

Catalog handling

Halotools supports reducing halo catalogs and caching them as fast-loading HDF5 files.checked 4 Oct 2026

Custom catalogs

Users can transform halo catalogs beyond those provided by Halotools into a standard form for its mock-population factories.checked 4 Oct 2026

Custom models

Its modular, object-oriented framework lets users design galaxy evolution models from interchangeable components.checked 4 Oct 2026

Dependencies

The installation documentation lists h5py 3.7 or later as an additional dependency that may be needed with conda or pip.checked 4 Oct 2026

Installation

The documentation recommends installing the latest release with conda-forge and also provides pip and source-build instructions.checked 4 Oct 2026

License

Halotools is fully open source and distributed under a 3-clause BSD-style license.checked 4 Oct 2026

Mock galaxies

It generates synthetic galaxy populations using HODs, abundance matching, and related methods.checked 4 Oct 2026

Notable model requirement

Different models require different halo properties, so users must format their catalog to supply the properties needed by the model they choose.checked 4 Oct 2026

Observables

Its algorithms calculate galaxy clustering, lensing, redshift-space distortions, and other astronomical statistics.checked 4 Oct 2026

Purpose

Halotools is a specialized Python package for building and testing galaxy-halo connection models and analyzing dark matter halo catalogs.checked 4 Oct 2026

Research audience

The package is designed to study cosmology, galaxy evolution, and structure formation using simulations and mock galaxy populations.checked 4 Oct 2026

Simulation data

The package supports downloading publicly available raw simulation catalogs, reducing them to memory-mapped files, and managing a simulation cache.checked 4 Oct 2026

Support

Users can request support by Slack or personal email, or raise a public GitHub issue tagged as a feature request or question.checked 4 Oct 2026