Detection of nonthermal emission from the bow shock of a massive runaway star

Winds from massive stars produce standing shocks in the surrounding interstellar medium, some of which are luminous. When moving, the star produces a bow shock in which it is possible to compress ambient magnetic fields and accelerate electrons to produce synchrotron emission, as shown in this paper. The star, BD+43^o3654, is a runaway O supergiant, suggesting that such objects may be detectable at higher energies owing to the up-scattering of background radiation. This paper presents new radio images and spectral maps that show nonthermal emission and gives a model for the origin of that emission.