Searching for Molecular Jets from High-mass Protostars

We report Very Large Array observations in the Q band toward 10 ionized jet candidates to search for SiO emission, a well-known shocked gas tracer. We detected 7 mm continuum counterparts toward 90% of the jet candidates. In most cases, the jet candidate is located toward the center of the 7 mm core, and the high masses (≈100 M _⊙ ) and densities (≈10 ^7 cm ^−3 ) of the cores suggest that the central objects are very young high-mass protostars. We detected SiO J = 1–0 emission associated with six target sources. In all cases, the morphology and spectrum of the emission is consistent with what is expected for molecular jets along an outflow axis, thus confirming the jet nature of 60% of our sample. Our data suggest a positive correlation between the SiO luminosity L _SiO , and both the bolometric luminosity L _Bol and the radio luminosity S _ν d ^2 of the driving sources.