ИСТИНА

In a rare and spectacular display, two well-known massive star forming regions W49N and G25.65, recently underwent maser 'super-burst' - their fluxes suddenly increasing above 30,000 and 18,000 Jy, respectively, several orders of magnitude above their usual values. In quick-response, ToO observations with the EVN, VLBA and KaVA were obtained, during a 4 week campaign - producing high-cadence multi-epoch VLBI investigation of the maser emission. The combination of high-resolution, polarisation and flux monitoring during the burst provides one of the best accounts, to date, of the super burst phenomenon and its relevance to the investigation of massive star formation.