About Gammapy


Gammapy is a community-developed, open-source Python package for gamma-ray astronomy.

It is an in-development affiliated package of Astropy that builds on the core scientific Python stack to provide tools to simulate and analyse the gamma-ray sky for telescopes such as CTA, H.E.S.S., VERITAS, MAGIC, HAWC and Fermi-LAT.

Gammapy is a place for Python-coding gamma-ray astronomers to share their code and collaborate.

Likelihood fitting of the morphology and spectrum of gamma-ray sources (using Sherpa), including multi-mission joint likelihood analysis and physical SED modeling (using Naima) is one important feature we’re working on. But Gammapy has a broader scope, we currently have code e.g. for data handling, background modeling, source detection, easy access to commonly used datasets and catalogs, statistical methods, even simulating Galactic source populations.

Feature requests and contributions welcome!

Gammapy is under very active development (see the Gammapy project summary on Open HUB and the Gammapy contributors page on Github). A 1.0 release and a paper are planned for 2016.

For now, please see the Gammapy poster and proceeding from ICRC 2015.

Acknowledging or Citing Gammapy

If you have used Gammapy in your scientific work we would appreciate it if you would acknowledge it.

Thank you, in advance, for your support.

For publications

For a publication, we recommend the following line be added to the conclusion or acknowledgements

This research has made use of Gammapy, a community-developed, open-source Python package for gamma-ray astronomy (citation).

For now, the citation is to the Gammapy ICRC 2015 conference proceeding.

If the journal allows please also include a link to https://github.com/gammapy/gammapy .

For presentations and posters

If you are making a presentation or poster featuring work/research that makes use of Gammapy, please include the Gammapy banner:


There’s also a smaller logo and variants with white text instead of black available here)


The following people have contributed to Gammapy (first name alphabetical order):

A detailed listing of contributions is here: Changelog.


We would like to say thank you to the people, institutions and collaborations that have supported Gammapy development!

  • Werner Hofmann and Jim Hinton (directors at MPIK Heidelberg) for giving PhDs and postdocs in the H.E.S.S. and CTA group time to work on Gammapy.
  • Google for sponsoring Manuel Paz Arribas to work on background modeling in Gammapy for GSoC 2015.
  • H.E.S.S. for providing a wonderful TeV gamma-ray dataset to develop the Gammapy code and methods (to collaboration members only). And specifically to the HOST (“HESS data analysis with open source tools”) task group within H.E.S.S. for exporting the data and IRFs to FITS format, making it available to Gammapy and other open source tools.
  • Fermi-LAT for making their data and software freely available and providing a wonderful GeV gamma-ray dataset, which was used to develop Gammapy.
  • CTA for promoting open source and working on the specification of open data formats, which are the basis of Gammapy data analysis and interoperability with other open source analysis packages (e.g. Gammalib/ctools or 3ML) and between different collaborations (e.g. H.E.S.S., VERITAS, MAGIC).
  • The Astropy project (core package, affiliated package, people) for creating a core Python package for astronomy. (Astropy is one of the building blocks on which Gammapy is built.)
  • The Sherpa developers and the Chandra X-ray observatory (CXC) for creating and maintaining a wonderful modeling / fitting package, and making Sherpa an open package on Github in 2015. (Sherpa is one of the building blocks on which Gammapy is built.)
  • Martin Raue for creating PyFACT and organising the first CTA data challenge in 2011. PyFACT (and a few other similar Python packages) can be considered precursors to Gammapy.
  • Everyone that contributed to Gammapy or used it for their research.

Papers using Gammapy

Here’s a list of papers using Gammapy.

If something is missing, please send an email to the Gammapy mailing list or to Christoph Deil if you prefer private communication.

[Owen2015]Owen et al. (2015), “The gamma-ray Milky Way above 10 GeV: Distinguishing Sources from Diffuse Emission”,
[Puelhofer2015]Pühlhofer et al. (2015), “Search for new supernova remnant shells in the Galactic plane with H.E.S.S.”,