Speaker
Description
The $\eta$ Carinae binary system hosts a massive stars featuring the highest known mass-loss rate. The two colliding winds dissipate mechanical energy in the shock, accelerating particles up to relativistic energies, and producing high-energy $\gamma$-rays. We analysed Fermi LAT data over two full orbital periods, comparing them with the predictions of particle acceleration in hydrodynamic simulations. We detected two distinct emission components: a low-energy component cutting off below 10 GeV, with short-term variability at periastron; an high-energy component varying by a factor 4, but differently during the two periastrons. This suggest a modification of the wind density in the inner wind collision zone, confirmed also in X-ray. Observations match the prediction of the particle in cell simulations. CTA and e-Astrogam could help to understand/constrain acceleration physics in more extreme conditions than in SNR.
