Abstract

Contributed Talk - Splinter MeVSky

Tuesday, 08 September 2026, 17:00   (MW-0337)

Probing acceleration mechanisms with high-energy spectro-polarimetry

Tristan Bouchet, Thomas Siegert
JMU Wuerzburg

High-energy spectro-polarimetry provides a powerful tool to probe particle acceleration, emission geometry, and accretion-ejection processes around compact objects. By combining spectral and polarization measurements, we investigated the origin of hard X-ray/soft γ-ray emission in the persistent black hole X-ray binaries (BHXB) Cygnus X-1 relying mainly on INTEGRAL data. We will highlight how the COSI mission can further constrain these emission mechanisms through improved MeV sensitivity and polarization capabilities. Beyond Cygnus X-1, COSI will enable studies of transient BHXBs, the Crab Nebula, and high-synchrotron peaked blazars, providing new insights into non-thermal emission and particle acceleration into those astrophysical sources.