Probing cosmic ray escape from Carinae

The binary stellar system eta Carinae is one of very few established astrophysical hadron accelerators. It seems likely that at least some fraction of the particles accelerated by eta Carinae escape from the system. Copious target material for hadronic interactions and associated gamma-ray emission exist on a wide range of spatial scales outside the binary system. This material creates a unique opportunity to trace the propagation of particles into the interstellar medium. In this work, we analyse gamma-ray data from Fermi-LAT of eta Carinae and surrounding molecular clouds and investigate the many different scales on which escaping particles may interact and produce gamma-rays. We find that interactions of escaping cosmic rays from eta Carinae in the wind region and the Homunculus Nebula could produce a significant contribution to the gamma-ray emission associated with the system. Furthermore, we detect excess emission from the surrounding molecular clouds. The derived radial cosmic-ray excess profile is consistent with a steady injection of cosmic rays by a central source. However, this would require a higher flux of escaping cosmic rays from eta Carinae than provided by our model. Therefore, it is likely that additional cosmic ray sources contribute to the hadronic gamma-ray emission from the clouds.