From December 18, 2017 13:15 until December 18, 2017 13:45
At Seminar Room
The collision of strong stellar winds in massive binary systems creates powerful shocks, which have been expected to accelerate particles to the MeV-GeV energy range through Fermi acceleration at the shock interface. Radio non-thermal emission is often observed, suggesting the presence of high energy synchrotron-emitting electrons. Collisions of high-energy electrons with stellar photons should also produce non-thermal high-energy X-rays and gamma-rays via the inverse-Compton mechanism, but observational confirmation of this emission has remained controversial. The NuSTAR observatory launched in 2012 has two X-ray focusing mirrors above 10 keV for the first time in space, which enables to measure high-energy non-thermal emission with a good sensitivity. I will introduce NuSTAR observations of the two binary systems, eta Car and WR140, around their recent periastron passages.