Class I methanol masers: Masers with EGOs

TL;DR

This study statistically demonstrates that approximately two-thirds of EGOs, identified as high-mass outflow candidates, are associated with class I methanol masers, providing a new large catalog for targeted searches and evolutionary studies.

Contribution

It establishes a statistical link between class I methanol masers and EGOs, offering a large candidate catalog for future research and insights into high-mass star formation evolution.

Findings

Approximately two-thirds of EGOs are associated with class I methanol masers.

The association provides a new large catalog of candidate sources.

This link helps compare evolutionary sequences of star formation.

Abstract

We have compared the results of a number of published class I methanol maser surveys with the catalogue of high-mass outflow candidates identified from the GLIMPSE survey (known as extended green objects or EGOs). We find class I methanol masers associated with approximately two-thirds of EGOs. Although the association between outflows and class I methanol masers has long been postulated on the basis of detailed studies of a small number of sources, this result demonstrates the relationship for the first time on a statistical basis. Despite the publication of a number of searches for class I methanol masers, a close physical association with another astrophysical object which could be targeted for the search is still lacking. The close association between class I methanol masers and EGOs therefore provides a large catalogue of candidate sources, most of which have not previously been searched for class I methanol masers. Interstellar masers and outflows have both been proposed to trace an evolutionary sequence for high-mass star formation, therefore a better understanding of the relationship between class I methanol masers and outflow offers the potential for comparison and amalgamation of these two evolutionary sequences.