Gammapy: An open-source Python package for gamma-ray astronomy

International audienceIn the past decade imaging atmospheric Cherenkov telescope arrays such as H.E.S.S., MAGIC, VERITAS, as well as the Fermi-LAT space telescope have provided high quality images and spectra of the γ-ray universe. Currently the γ-ray community is preparing to build the nextgeneration Cherenkov Telecope Array (CTA), which will be operated as an open observatory. Gammapy v0.3 (available at https://github.com/gammapy/gammapy under the open-source BSD license) is a new in-development Astropy affiliated package for high-level analysis and simulation of astronomical γ-ray data. It is built on the scientific Python stack (Numpy, Scipy, matplotlib and scikit-image) and makes use of other open-source astronomy packages such as Astropy, Sherpa and Naima to provide a flexible set of tools for γ-ray astronomers. We present an overview of the Gammapy scope, development workflow, status, structure, features, application examples and goals. We would like Gammapy to become a community-developed project and a place of collaboration between scientists interested in γ-ray astronomy with Python. Contributions welcome