Detection of periodic flares in 6.7 GHz methanol masers G45.804-0.356 and G49.043-1.079

TL;DR

This study reports the discovery of two new periodic methanol masers with periods of approximately 417 and 469 days, providing insights into high-mass star-forming regions and suggesting possible accretion-related mechanisms.

Contribution

The paper identifies and characterizes two new periodic methanol masers, expanding knowledge of maser variability and its potential physical causes.

Findings

G45.804-0.356 has a period of 416.9 days.

G49.043-1.079 has a period of 469.3 days.

Infrared variability in G49.043-1.079 is simultaneous with maser flares.

Abstract

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 32m 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.