New Observations of 95.2 GHz Class I Methanol Maser in the G24 Region: Implications for Star Formation Rate from the Milky Way to External Galaxies

Abstract We report the detection of collisionally pumped 95.2 GHz (J = 80–71 A+) class I methanol masers in the Galactic G24 region, which lies near the interface between the Galactic bar and a spiral arm—a location potentially affected by bar-driven shocks. Using the Purple Mountain Observatory (PMO) 13.7 m telescope, we carried out on-the-fly (OTF) mapping and single-pointing observations, leading to the detection of 12 sources at 95.2 GHz, including one newly identified source toward the direction of G24. The G24-associated masers exhibit significantly higher luminosities than typical Galactic class I methanol masers, though still much fainter than extragalactic counterparts. A comparative analysis reveals a tight correlation between star formation rate (SFR) and class I maser luminosity from the G24 region to the Galactic Center and further to external galaxies, reinforcing the use of class I methanol masers as reliable tracers of star formation across diverse Galactic and extragalactic environments.