We present high-resolution S-band (3.1 GHz) radio continuum observations of eleven massive young stellar objects (MYSOs) selected for their extended morphology in the 1.3 GHz SARAO MeerKAT Galactic Plane Survey. The improved angular resolution of ~3.1″ enabled the separation of jet structures into multiple spatially resolved components. Morphological analysis reveals a diverse range of structures, including bipolar jets, double-hotspot bow-shocks, and diffuse emission, with some outflows extending to parsec scales (up to ~4 pc) and injecting substantial momentum into their environments. Some of the sources exhibit clear signatures of jet bending and precession, with derived precession periods ranging from 150 to 800 years. Spectral indices of the sources were derived from datasets with comparable uv-coverage to minimise frequency-dependent flux-loss biases. The resulting spectral indices span a wide range from α ≈ −2.25 to +2.22, confirming a mixture of optically thin non-thermal and optically thick thermal emission. Non-thermal emission is highly prevalent, being detected in 10 of the 11 observed MYSO systems. At the component level, approximately half of the resolved radio features exhibit negative spectral indices consistent with synchrotron emission. The detection of synchrotron emission in the shocks provides strong evidence for diffusive shock acceleration, while diffuse non-thermal envelopes suggest potential particle acceleration via magnetic reconnection. These results highlight the crucial role of magnetic fields in the propagation of massive protostellar jets.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)