The GammaLib is a versatile toolbox for the high-level analysis of astronomical gamma-ray data. It is implemented as a C++ library that is fully scriptable in the Python scripting language. The library provides core functionalities such as data input and output, interfaces for parameter specifications, and a reporting and logging interface. It implements instruments specific functionalities such as instrument response functions and data formats. Instrument specific functionalities share a common interface to allow for extension of the GammaLib to include new gamma-ray instruments. The GammaLib provides an abstract data analysis framework that enables simultaneous multi-mission analysis.

GammaLib does not rely on any third-party software, except of HEASARC's cfitsio library that is used to implement the FITS interface. Large parts of the code treat gamma-ray observations in an abstract representation, and do neither depend on the characteristics of the employed instrument, nor on the particular formats in which data and instrument response functions are delivered. Instrument specific aspects are implemented as isolated and well defined modules that interact with the rest of the library through a common interface. This philosophy also enables the joint analysis of data from different instruments, providing a framework that allows for consistent broad-band spectral fitting or imaging. So far, GammaLib supports analysis of COMPTEL, Fermi/LAT, and Cherenkov telescope data (CTA, H.E.S.S., MAGIC, VERITAS).

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