The SOMA Radio Survey. I. Comprehensive SEDs Of High-Mass Protostars From Infrared To Radio And The Emergence Of Ionization Feedback

TL;DR

This study constructs detailed spectral energy distributions of high-mass protostars from radio to infrared, using archival data to test star formation models and examine ionization feedback and multiplicity.

Contribution

It provides extended SEDs for high-mass protostars and demonstrates how centimeter continuum data constrain star formation models and protostellar properties.

Findings

Interferometric centimeter data constrain ionizing luminosity.

Derived parameters align with dynamical mass estimates.

Low stellar multiplicity observed in the regions.

Abstract

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.