FITS images of 24 bow-shock candidates

A subset of these were also observed and detected with Effelsberg at 4-8GHz. The VLA-derived spectral index maps indicate non-thermal emission for most sources, but the statistical uncertainties are large for most sources and all Effelsberg observations indicate thermal emission. Assuming thermal emission, we obtain upper limits on the electron density within the shocked layer.

We obtained upper limits on radio emission from the bow shock of Zeta Oph at a similar flux level to predictions from magnetohydrodynamic simulations. Our survey marks a significant addition to the ca. 10 previously known radio-emitting bow shocks in the literature, and demonstrates that deep, targeted radio surveys can have a good success rate in detecting IR-selected bow shocks. Follow-up observations of these targets at lower and higher frequencies are encouraged to determine whether any are non-thermal emitters like the bow shocks of BD+433654, BD+602522, and LS2355.