A high-sensitivity 6.7 GHz methanol maser survey toward H2O sources

TL;DR

This survey used the Effelsberg telescope to detect faint 6.7 GHz methanol masers near water masers, revealing their exclusive association with massive star formation and expanding the known population with new detections.

Contribution

It presents the first high-sensitivity survey of 6.7 GHz methanol masers toward water maser sources, discovering 10 new faint masers and confirming their link to massive star formation.

Findings

10 new methanol masers detected

Faint masers are associated with massive stars

No methanol masers found in low-mass star regions

Abstract

We present the results of a high sensitivity survey for 6.7 GHz methanol masers towards 22 GHz water maser using the 100 m Efflesberg telescope. A total of 89 sources were observed and 10 new methanol masers were detected. The new detections are relatively faint with peak flux densities between 0.5 and 4.0 Jy. A nil detection rate from low-mass star forming regions enhances the conclusion that the masers are only associated with massive star formation. Even the faintest methanol maser in our survey, with a luminosity of 1.1 $10^{-9} L_\odot$ is associated with massive stars as inferred from its infrared luminosity.