The bursting variability of 6.7 GHz methanol maser of G33.641-0.228

From 2014 to 2015, we conducted a total of 469 days observation of the 6.7 GHz methanol maser in a star forming region G33.641-0.228, known to be a bursting maser source. As a result, eleven bursts were detected. On MJD 57364, the flux density grew by more than six times w.r.t the day before. Moreover, during the largest burst, the flux density repeatedly increased and decreased rapidly with time-scale as short as 0.24 day. Since these characteristics of the burst are similar to the solar burst, we speculate that the burst of the 6.7 GHz methanol maser in G33.641-0.228 might occur with a similar mechanism of the solar burst.