Weak and Compact Radio Emission in Early High-mass Star-forming Regions. II. The Nature of the Radio Sources

Abstract

In this study we analyze 70 radio continuum sources that are associated with dust clumps and which are considered to be candidates for the earliest stages of high-mass star formation. The detection of these sources was reported by Rosero et al., who found most of them to show weak (< 1 mJy) and compact (< 0.″6) radio emission. Herein, we used the observed parameters of these sources to investigate the origin of the radio continuum emission. We found that at least ∼30% of these radio detections are most likely to be ionized jets associated with high-mass protostars. However, for the most compact sources, we cannot discard the scenario that they represent pressure-confined H II regions. This result is highly relevant for recent theoretical models that are based on core accretion, which predict the first stages of ionization from high-mass stars to be in the form of jets. Additionally, we found that properties such as the radio luminosity as a function of the bolometric luminosity of ionized jets from low and high-mass stars are extremely well-correlated. Our data improve upon previous studies by providing further evidence of a common origin for jets independently of luminosity.