Galactic Dynamics is the study of the formation, history, and evolution of galaxies using the orbits of objects — numerically-integrated trajectories of stars, dark matter particles, star clusters, or galaxies themselves.

gala is an Astropy-affiliated Python package that aims to provide efficient tools for performing common tasks needed in Galactic Dynamics research. Much of this code uses Python for flexible, user-friendly interfaces that interact with wrappers around low-level code (primarily C) to enable fast computations. Common operations include gravitational potential and force evaluations, orbit integrations, dynamical coordinate transformations, and computing chaos indicators for nonlinear dynamics. gala heavily uses the units and astronomical coordinate systems defined in the Astropy core package (astropy.units and astropy.coordinates).

This package is being actively developed in a public repository on GitHub, and we are always looking for new contributors! No contribution is too small, so if you have any trouble with this code, find a typo, or have requests for new content (tutorials or features), please open an issue on GitHub.


Welcome to the new Gala documentation! The documentation has a new theme and some new content. Use the links in the nav bar above, the page listing below, or the search bar on the left to dive in!


Main author: Adrian Price-Whelan (@adrn)

All contributors (alphabetical last name):

  • Johnny Greco

  • Sergey Koposov

  • Daniel Lenz

  • Pey Lian Lim

  • Syrtis Major

  • Semyeong Oh

  • Brigitta Sipocz

  • Nathaniel Starkman

Citation and Attribution


Here is a list of papers that use Gala

If you make use of this code, please cite the JOSS paper:

  doi = {10.21105/joss.00388},
  url = {},
  year = 2017,
  month = {oct},
  publisher = {The Open Journal},
  volume = {2},
  number = {18},
  author = {Adrian M. Price-Whelan},
  title = {Gala: A Python package for galactic dynamics},
  journal = {The Journal of Open Source Software}

Please also cite the Zenodo DOI DOI of the version you used as a software citation:

  author       = {Adrian Price-Whelan and
                  Brigitta Sipőcz and
                  Daniel Lenz and
                  Johnny Greco and
                  Nathaniel Starkman and
                  Dan Foreman-Mackey and
                  P. L. Lim and
                  Semyeong Oh and
                  Sergey Koposov and
                  Syrtis Major},
  title        = {adrn/gala: v1.3},
  month        = oct,
  year         = 2020,
  publisher    = {Zenodo},
  version      = {v1.3},
  doi          = {10.5281/zenodo.4159870},
  url          = {}