The SOMA Radio Survey. I. Comprehensive SEDs Of High-Mass Protostars
  From Infrared To Radio And The Emergence Of Ionization Feedback
  We study centimeter continuum emission of eight high- and intermediate-mass
protostars that are part of the SOFIA Massive (SOMA) Star Formation Survey,
thus building extended spectral energy distributions (SEDs) from the radio to
the infrared. We discuss the morphology seen in the centimeter continuum
images, which are mostly derived from archival VLA data, and the relation to
infrared morphology. We use the SEDs to test new models of high-mass star
formation including radiative and disk-wind feedback and associated free-free
and dust continuum emission (Tanaka, Tan, & Zhang 2016). We show that
interferometric data of the centimeter continuum flux densities provide
additional, stringent tests of the models by constraining the ionizing
luminosity of the source and help to break degeneracies encountered when
modeling the infrared-only SEDs, especially for the protostellar mass. Our
derived parameters are consistent with physical parameters estimated by other
methods such as dynamical protostellar masses. We find a few examples of
additional stellar sources in the vicinity of the high-mass protostars, which
may be low-mass young stellar objects. However, the stellar multiplicity of the
regions, at least as traced by radio continuum emission, appears to be
relatively low.
