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We present a study of the radio continuum source found near the position of the H$_2$O masers and the Turner--Welch source in the W3OH region. The source spectrum from 1.6 to 15 GHz exhibits a power law with spectral index $-0.6$. The continuum source is elongated in the East-West direction and its size decreases linearly with increasing frequency. These observations provide strong evidence for synchrotron emission from an inhomogeneous source.
The elongated continuum source is coincident within 0.1 arcsec of the center of expansion of the H$_2$O masers and is aligned with the dominant H$_2$O outflow pattern. A possible model for the system includes an early-type star with a fast collimated wind that drives a jet-like outflow. Fast shocks in the wind or jet accelerate electrons, via a first-order Fermi process, to relativistic speeds necessary for synchrotron emission. The jet impinges on the surrounding molecular material and shocks and accelerates this material, leading to the motions observed in the H$_2$O masers.
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