High-cadence 6.7 GHz methanol maser monitoring observations by Hitachi 32-m radio telescope

We started high-cadence monitoring observations of 6.7 GHz methanol masers from Dec. 2012 using Hitachi 32-m radio telescope (Yonekura et al.(2016). Observations have been conducted basically every day. On average, 13 hours of observations have been made per day, amounting to 4000-5000 hours per year. The cadence varies by sources: one observation in 1-50 days. In addition to already known 29 sources (Tanabe et al. 2023 and references therein), we have newly identified ∼20 sources with periodic flux variability. We have also detected 5 sources with sudden flux rises in 2019-2022, including G358.93-0.03 which was confirmed to be associated with the accretion burst.