The detection of young stellar objects (YSOs) in early VLA observations was essentially limited to the strongest sources, namely free-free thermal emission from photoionized HII regions associated with young massive stars and non-thermal gyrosynchrotron emission from the active magnetosphere of some low-mass PMS stars (typically T-Tauris). Current VLA observations can reach microJy sensitivities and radio emission from a wide variety of YSOs, including the youngest deeply embedded protostars, is readily detected. Thermal free-free radio jets have been found associated with protostars spanning a wide range of masses and luminosities, from the most massive O-type protostars to very low-luminosity objects (VeLLOs) and proto-brown dwarf candidates. Non-thermal synchrotron radio emission, probably associated with strong shocks, has also been identified in the lobes of jets at relatively large distances from the source. Finally, cm radio emission has also been found associated with accretion disks around YSOs, either tracing the ionized photoevaporating disk or the dust emission. However, establishing the nature of a radio source is often not an easy task. I will summarize our current knowledge of radio emission from YSOs, with emphasis on radio jets, to build a self-consistent picture for the interpretation of their properties, to distinguish them from photoionized HII regions, and to relate the radio emission to the luminosity and evolutionary stage of protostars of all masses.

Comunicación oral presentada al congreso: The Past, Present, and Future of the VLA: Celebrating 40 Years - the meeting will be held virtually on August 4 - 6, 2021, broadcasting from Socorro, NM, USA, and will conclude with a virtual public event on Saturday, August 7th-.

With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709