Abstract

Invited Talk - Splinter MeVSky

Tuesday, 08 September 2026, 16:25   (MW-0337)

From Data Challenges to COSI Science

Chris Karwin, Steven Boggs, Dieter Hartmann, Carolyn Kierans, John Tomsick, Andreas Zoglauer, Igor Moskalenko, Thomas Siegert, and the COSI Science Team
Clemson University, University of California San Diego, Clemson University, NASA Goddard Space Flight Center, University of California Berkeley, University of California Berkeley, Stanford University, University of Wurzburg

In preparation for COSI’s anticipated 2027 launch, the COSI Collaboration has developed a series of Data Challenges (DCs) based on realistic simulations of expected flight observations. These challenges support the development and validation of the end-to-end analysis pipeline, while also providing the broader community with realistic datasets for developing and testing analysis methods. In this talk, I will introduce the COSI Data Challenges and highlight some results from the latest and most comprehensive challenge, DC4. These results demonstrate COSI’s ability to reconstruct and characterize MeV emission across a broad range of science cases and provide a realistic view of the sky as observed by a NASA Small Explorer–class MeV mission. I will then focus on the Galactic diffuse continuum emission (GDCE), a key probe of cosmic-ray electrons and a dominant component of the MeV sky. Using state-of-the-art GALPROP models and the modern COSIPy analysis framework, I will show how DC4 is being used to develop the tools needed to disentangle the physical components of the diffuse emission. I will also highlight the connection between the GDCE and positron in-flight annihilation, which provides an important avenue for addressing the long-standing mystery of the origin of Galactic positrons.