ICC-DAM PhD lecture. Xavier Paredes-Fortuny: Observational and theoretical study of the interaction of relativistic winds from young pulsars with inhomogeneous stellar winds

Simulations of gamma-ray binaries hosting a Be star suggest that the circumstellar disk is disrupted during the periastron passage of the compact object.

The disk contribution to the optical photometry is a fraction of the total emission, therefore orbital optical variability can be associated to changes in the circumstellar disk. We conducted long-term optical photometric and Halpha EW observations of the gamma-ray binary LS I +61 303, resulting in the discovery of the coupling between the thermal and non-thermal emission processes in the gamma-ray binary LS I +61 303.

Gamma-ray binaries hosting a massive star and a young pulsar present strong interaction between the relativistic pulsar wind, and the wind of the stellar companion. The two-wind interaction region might suffer the impact of an inhomogeneous stellar wind (hereafter clumps), making its dynamics and hence its radiative output more complex.

We conducted RHD simulations of this interaction, showing the strong impact of the arrival of clumps on the whole interaction structure, and providing a framework for the short time-scale flux variability of the non-thermal radiation in gamma-ray binaries.