  We consider Thomson-like processes between dark matter dark photons and free
electrons in the Milky Way. The result is a radio signal background that can be
detectable with current or future radio telescope arrays. In particular, we
computed sensitivity prospects for the Atacama Large Millimeter Array (ALMA)
radio telescope and for the future Square Kilometer Array (SKA), concluding
that unconstrained parameter space in a wide range of dark photon masses can be
probed.
