Astronomy Preserved – INTEGRAL/SPI 22-yr Soft Gamma-Ray Source Catalogue

• Applicant: Dr. Thomas Siegert
• Subject Area: Astrophysics and Astronomy
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 551127478

Despite more than two decades of astronomical observations at soft gamma-ray wavelengths with satellite-based instrumentation, there exists no wholesome and state-of-the-art compendium of detected sources in the sky. Since 2002, the spectrometer telescope SPI aboard ESA's INTEGRAL mission has observed hundreds of different objects and the glow of the Milky Way galaxy itself. While SPI is the most sensitive soft gamma-ray telescope today, the reduction of its measurements towards science-ready data products is tedious and only mastered by specialists. By the end of 2024, the scientific operations of INTEGRAL will cease, for which reason ESA has been calling for community input towards its planned INTEGRAL Science Legacy Archive, ISLA. In this project, the full 22-year dataset of SPI will be analyzed to construct an openly accessible catalogue of soft gamma-ray sources. This catalogue will include the brightness of the sources as a function of wavelength and their possible time variability, as well as images of the extended emission in the Milky Way. In a collaboration of three German institutes, a general data analysis pipeline will be established, data products created, and results independently validated. Together with partners at ESA, these results will be implemented into the ISLA for long-term preservation. In addition, the astronomical community will be enabled to obtain information on user-specified input beyond the catalogue through an online application. In the light of upcoming, future, soft gamma-ray telescopes, such as NASA's COSI mission, this project will serve as a benchmark for how to construct and maintain the scientific results at these peculiar wavelengths.

• DFG Programme: Cataloguing and Digitisation (Scientific Library Services and Information Systems)
• Participating Institution: Friedrich-Alexander-Universität Erlangen-Nürnberg; Dr. Karl Remeis-Sternwarte Bamberg; Astronomisches Institut; Eberhard Karls Universität Tübingen; Julius-Maximilians-Universität Würzburg; Max-Planck-Institut für extraterrestrische Physik (MPE)
• Co-Investigators: Dr. Lorenzo Ducci; Thomas Stanke, Ph.D.