Collision of stellar winds in the WR 146 and WR 147 binary systems

Abstract

Binary systems of early-type massive stars, O and Wolf-Rayet type, which emit strong winds, present a colliding-wind region. In this area, charged particles are accelerated to relativistic velocities and, due to the fact that they are in the presence of a magnetic field, there is non-thermal radio emission. The flux density measured from these systems also includes the thermal emission coming from the individual winds. The two systems studied in this paper are WR 146 and WR 147, both of them located in the Cygnus constellation. We fit a model for the observed spectrum that takes into account thermal and nonthermal emission, as well as an expected thermal absorption due to the ionized attenuating medium, ignoring other processes like synchrotron self-absorption (SSA) or the Razin-Tsytovich effect (RTe). We study from the results whether these three processes explain the spectrum of WR 146 and WR 147 or not. Finally, we conclude that it is not necessary to include SSA or RTe to explain the flux density