COMPTEL data analysis using GammaLib and ctools

TL;DR

This paper introduces open source software based on GammaLib and ctools for modern, comprehensive analysis of archived COMPTEL gamma-ray data, enabling new scientific insights from 20-year-old measurements.

Contribution

The authors developed and validated a new software framework that allows the analysis of COMPTEL data using current gamma-ray astronomy tools, making the data publicly accessible and scientifically useful.

Findings

Software reproduces previous COMPTEL data products

Software replicates published COMPTEL scientific results

Enables new analysis of archived gamma-ray data

Abstract

More than 20 years after the end of NASA's Compton Gamma-Ray Observatory mission, the data collected by its Imaging Compton Telescope (COMPTEL) still provide the most comprehensive and deepest view of our Universe in MeV gamma rays. While most of the COMPTEL data are archived at NASA's High Energy Astrophysics Science Archive Research Center (HEASARC), the absence of any publicly available software for their analysis means the data cannot benefit from the scientific advances made in the field of gamma-ray astronomy at higher energies. To make this unique treasure again accessible for science, we developed open source software that enables a comprehensive and modern analysis of the archived COMPTEL telescope data. Our software is based on a dedicated plug-in to the GammaLib library, a community-developed toolbox for the analysis of astronomical gamma-ray data. We implemented high-level scripts for building science analysis workflows in ctools, a community-developed gamma-ray astronomy science analysis software framework. We describe the implementation of our software and provide the underlying algorithms. Using data from the HEASARC archive, we demonstrate that our software reproduces derived data products that were obtained in the past using the proprietary COMPTEL software. We furthermore demonstrate that our software reproduces COMPTEL science results published in the literature. This brings the COMPTEL telescope data back into life, allowing them to benefit from recent advances in gamma-ray astronomy, and gives the community a means to unveil its still hidden treasures.