Poster Presentation

The Evolutionary Status of Methanol Maser Sources

Author(s): Bethany Jones (University of Manchester); Gary Fuller (University of Manchester); The MMB Survey team

Presenter: Bethany Jones (University of Manchester)

Emitting strongly at 6.7\,GHz, class II methanol masers are exclusively associated with sites of high-mass star formation.
The methanol masers are pumped by warm dust emission from a high mass protostellar object, yet the relationship between the properties of the observed maser emission and the young stellar objects hosting them remains relatively poorly understood.
The Methanol Multibeam Survey (MMB; Green et al 2009, 2017) provides a sample of over 1000 methanol masers from an unbiased survey of the Galactic plane up to longitude 60 degrees.
The compact source catalogues produced from the \textit{Herschel} infrared Galactic plane survey (Hi-GAL) provide a complementary data set at far-infrared wavelengths to identify the host star--forming clumps in dust emission.

We perform fitting to the far-infrared spectral energy distributions of the maser host clumps to determine their properties for comparison against existing catalogues of the general Galactic population of massive protostellar clumps.
The methanol maser phase can then be placed in the evolutionary sequence of high--mass star formation and limits set on the clump properties required to sustain a methanol maser.
The fraction of protostellar clumps falling within this determined parameter space but lacking a maser detection in turn constrains the population of as yet undetected maser sources and the beaming angle of methanol maser emission.
Finally, the protostellar objects in the northern Galactic plane with the necessary properties to host a methanol maser give an estimate of the number of additional detections expected through completion of the MMB survey.