The open-source software package Gammapy has been selected by the CTA observatory for the analysis of data collected by its future network of telescopes being deployed in Chile and the Canary Islands. Gammapy has seen contributions from over 70 scientists around the world.
CTA will operate as an open observatory
The analysis of observational data in ground-based gamma-ray astronomy requires specialised analysis methods and software in order to reach the highest possible sensitivity in the fight against the background ’noise’ of charged cosmic rays. Traditionally, both the data and corresponding analysis software belonged to the collaborations operating the instruments and were often not publicly available. However, the future Cherenkov Telescope Array (CTA) will be operated as an open observatory, with public access to the observational data for scientific users, together with openly accessible analysis software.
An open source library dedicated to gamma astronomy
In the past decade, the Python programming language has been established as a new standard in the analysis of scientific data, and a whole ecosystem of open-source software packages has developed around it. These software packages cover many diverse fields, such as Biology, Geoscience, Chemistry, and Astronomy, and are used by millions of scientists world-wide for their daily work. Thanks to an open and shared development mode, scientists not only save time, but also use common software projects to exchange with colleagues and collaborate across multiple disciplines.
Major effort by the MPIK and APC laboratories
In 2012, inspired by this movement, two young researchers from MPIK of Heidelberg (Germany) started an open source Python package for the analysis of gamma-ray data, in particular from the H.E.S.S. telescope array. From 2015, Gammapy was developed as a prototype of a future analysis software for CTA, but also with a view to sharing with other research groups in gamma astronomy. With common analysis software and in open development, the path has been opened to use data from multiple instruments and to obtain combined measurements with much better accuracy. With the growing involvement of researchers from the APC laboratory (IN2P3 / CNRS - University of Paris, Paris Observatory and CEA), the project was structured in 2017 around an international steering committee. Gammapy has grown constantly over time, and seen contributions from more than 70 scientists (researchers and students) from ten different countries, mainly around the Franco-German duo of the APC and MPIK laboratories.
Optimized with HESS, MAGIC and VERITAS experiments
In the past few years, Gammapy has already been successfully used for the analysis of data from existing imaging atmospheric Cherenkov telescopes such as H.E.S.S., MAGIC and VERITAS, and is beginning to be used for gamma-ray experiments using ground-based particle detectors such as HAWC. On the 1st of June last, Gammapy was selected by the CTA Observatory as the official high-level analysis Science Tools. The successful proposal was formally supported by partners from Germany (MPIK, ECAP, DESY), France (APC, LUTh/INSU-Paris Observatory, IRFU/CEA, LUPM/IN2P3, LPNHE/IN2P3, CENBG/IN2P3), Spain (UCM, IAA-CSIC), and Italy (INAF). With this role as CTA Science Tools, Gammapy will be used by many more researchers in future and will contribute to simplifying the combination of data from multiple observatories and to establishing a new standard for open and reproducible scientific analysis in gamma-ray astronomy.
The Cherenkov Telescope Array (CTA) is an international project led by more than 30 countries and dedicated to the study of very high energy cosmic phenomena through the detection of gamma rays from the ground. With dozens of telescopes planned at two sites, one in the northern hemisphere on the island of La Palma, Spain, and the other in the southern hemisphere near Paranal, Chile, CTA will be the most important gamma-ray observatory in the world for the coming decades, following on from the current generation of telescopes in operation, such as the H.E.S.S network in Namibia, where the CNRS (IN2P3 / INSU) was involved from its design phase more than twenty years ago. CTA will extend observations into the higher energy part of the electromagnetic spectrum, with unmatched performance. In addition to a better understanding of the extreme Universe, CTA will make it possible to use gamma rays to provide valuable data on the history of the evolution of the Universe, the indirect search for dark matter, or the question of the formation of structures. CTA will be the first ground-based gamma astronomy observatory open to global research communities.
Contacts at IN2P3:
Vincent Poireau, Astroparticle and Cosmology Deputy Scientific Director
Le Prototype LST-1 de CTA détecte une émission à très haute énergie en direction du Pulsar du Crabe (actualité du 23 juin 2020) : https://in2p3.cnrs.fr/fr/cnrsinfo/le-prototype-lst-1-de-cta-detecte-une-emission-tres-haute-energie-en-direction-du-pulsar
Cherenkov Telescope Array, un projet en cours de construction (actualité du 16 mai 2018) : https://www.in2p3.cnrs.fr/fr/cnrsinfo/cherenkov-telescope-array-un-projet-en-cours-de-construction
Site internet officiel de l’observatoire CTA : https://www.cta-observatory.org/
- Astrophysique à Haute Energie