Star Formation, Stellar Feedback, and the Ecology of Galaxies

Star Formation, Stellar Feedback, and the Ecology of Galaxies

The puzzle of the methanol maser rings - physical properties and molecular gas emission tracers

Direct studies of high-mass star-forming regions are difficult due to their large distances, high densities of their birth clouds, and rapid evolution. Class II methanol masers are a useful tool for studying processes close to the forming star as their bright and compact emission allows their detection on mas scales. However, it is unclear if the maser emission is tracing the accretion disk or the footprint of the jet/outflow system. The European VLBI Network (EVN) allowed the detection of methanol maser rings in high-mass star-forming regions. These rings suggest a connection with the accretion disk, but the proper motion studies indicate expansion. To resolve the dust and gas at similar spatial scales, we observed five of those rings with the Atacama Large Millimeter/submillimeter Array (ALMA). I will present the first results of one of these sources in which the molecular line emission traces a ring-like morphology with a velocity gradient, similar to an accretion disk. The methanol maser ring coincides with the molecular ring. Existing ALMA observations from the Large Program ALMAGAL allow to put the molecular ring into the context of emission at larger scales.