Relativistic Astrospheres of Pulsars and Gamma-Ray Binaries: Modeling of Non-thermal Processes

Abstract

Relativistic winds of the rotation powered pulsars in binary systems colliding with powerful winds of massive stars are producing astrospheres which are observed as bright gamma-ray sources above TeV photon energies. A long standing problem in high energy astrophysics is the nature of galactic accelerators of particles above PeV energies which are the sources of galactic cosmic rays and are producing PeV regime photons observed by ground based observatories. Recent 2D RMHD modeling revealed that gamma-ray binaries which harbor Gauss-range magnetic field in the winds collision region can accelerate particles above PeV. We present here 2D and 3D simulations of local structure of the winds collision region in gamma-ray binaries and show that in both cases the structures of magnetized flows are favorable for PeV proton acceleration. The strong magnetization of the winds of young massive stars results in prominent anisotropic shape of the relativistic pulsar wind astrosphere and may strongly affect the non-thermal emission of gamma-ray binaries. The sources can be bright in MeV emission regime and can indeed be the sources of PeV energy protons.