The physical parameters of clumps associated with class I methanol masers

TL;DR

This study investigates the association between class I methanol masers and cold dust clumps from the ATLASGAL survey, revealing that masers are linked to denser, more luminous, and warmer clumps, and differ in spatial distribution from class II masers.

Contribution

It provides the first comprehensive analysis of physical parameters of clumps associated with class I methanol masers, highlighting their distinct environmental conditions and spatial offsets.

Findings

Almost 100% of class I methanol masers are associated with ATLASGAL sources.

Masers are found in clumps with higher densities, luminosities, and temperatures.

Class I masers are generally located farther from the peak submillimetre emission than class II masers.

Abstract

We present a study of the association between class I methanol masers and cold dust clumps from the ATLASGAL survey. It was found that almost 100% of class I methanol masers are associated with objects listed in the ATLASGAL compact source catalog. We find a statistically significant difference in the flux density, luminosity, number and column density and temperature distributions of ATLASGAL sources associated with 95/44 GHz methanol masers compared with those ATLASGAL sources devoid of 95 GHz methanol masers. The masers tend to arise in clumps with higher densities, luminosities and temperatures compared with both the full sample of the ATLASGAL clumps, as well as the sample of ATLASGAL sources that were cross-matched with positions previously searched for methanol masers but with no detections. Comparison between the peak position of ATLASGAL clumps and the interferometric positions of the associated class I and II methanol masers reveals that class I masers are generally located at larger physical distances from the peak submillimetre emission than class II masers. We conclude that the tight association between ATLASGAL sources and class I methanol masers may be used as a link toward understanding the conditions of the pumping of these masers and evolutionary stages at which they appear.