Colliding-wind binary systems: diffusive shock acceleration and non-thermal emission

J. M. Pittard, G. S. Vila, G. E. Romero.

Serie: Trabajos publicados del IAR ; no. 1559

Resumen: We present a model for the non-thermal emission from a colliding-windbinary. Relativistic protons and electrons are assumed to be acceleratedthrough diffusive shock acceleration (DSA) at the global shocks boundingthe wind-wind collision region. The non-linear effects of thebackreaction due to the cosmic ray pressure on the particle accelerationprocess and the cooling of the non-thermal particles as they flowdownstream from the shocks are included. We explore how the non-thermalparticle distribution and the keV-GeV emission changes with the stellarseparation and the viewing angle of the system, and with the momentumratio of the winds. We confirm earlier findings that DSA is veryefficient when magnetic field amplification is not included, leading tosignificantly modified shocks. We also find that the non-thermal fluxscales with the binary separation in a complicated way and that theanisotropic inverse Compton emission shows only a moderate variationwith viewing angle due to the spatial extent of the wind-wind collision.