GammaLib is a versatile toolbox for the scientific analysis of astronomical gamma-ray data. It consists of a C++ library and a Python module that exposes the full functionality of the library to Python. The library provides an abstract data analysis framework that is independent of any specific gamma-ray telescope. Instrument specific aspects, such as handling of data formats and response functions, are implemented as isolated and well defined modules sharing an identical abstract interface. This enables a joint multi-instrument analysis of data, allowing for consistent broad-band spectral fitting or imaging. So far, GammaLib supports analysis of data obtained with CGRO/COMPTEL, Fermi/LAT, INTEGRAL/SPI and Cherenkov telescopes (CTA, H.E.S.S., MAGIC, VERITAS).

Except for HEASARC's cfitsio library that is used to implement the FITS interface, GammaLib does not rely on any third-party software. All functionalities are implemented natively.

GammaLib is developed by a community of enthousiastic gamma-ray astronomers with support from engineers. The lead institute is


As of today there have been contributions by the following institutions:


We regularily organise coding sprints where key developers but also newcomers meet to discuss the developments and next steps, and advance with the coding of the software.

GammaLib is free software distributed under the GNU GPL license version 3