The Compton Spectrometer and Imager (COSI) is a Small Explorer satellite mission scheduled to launch in 2027. COSI primarily detects gamma-ray photons between 0.2 - 5 MeV via Compton scattering, and it acts as a spectrometer, wide-field imager, and polarimeter. In preparation for the upcoming mission, the COSI Collaboration has been developing the data analysis pipelines. To help support this effort we are conducting yearly data challenges. The two primary goals of this are to aid in the software development and help prepare the scientific community for analyzing COSI data. 

The 4th COSI Data Challenge is now publicly available and can be found here on the Data Challenge GitHub page.

This Data Challenge coincides with an updated (alpha) release of our official high-level analysis tools, cosipy. We would like to encourage anybody who is interested in learning more about COSI and Compton telescopes to participate in the Data Challenge! Everything needed can be found at the above link, including contact information. Any feedback is welcomed and would be much appreciated!