SIMBAD references

Context. Periodicity in 6.7 GHz methanol maser sources is a rare phenomenon that was discovered during long-term monitoring programmes. Understanding the underlying processes that lead to periodic variability might provide insights into the physical processes in high-mass star-forming regions.
Aims. We aim to identify and describe new periodic methanol masers.
Methods. The observations were obtained with the Torun 32 m antenna. Time series analysis was conducted using well-proven statistical methods. Additionally, NEOWISE data were used to search for a correlation between infrared and maser fluxes.
Results. We found two new periodic sources, G45.804-0.356 and G49.043-1.079, with periods of 416.9 and 469.3 days, respectively. For G49.043-1.079, infrared variability is simultaneous with methanol flares.
Conclusions. A most likely cause of the periodicity in G49.043-1.079 is modulated accretion. For G45.804-0.356, the periodicity cannot be explained with the available data, and further research is needed.