Models of class II methanol masers based on improved molecular data

Abstract

The class II masers of methanol are associated with the early stages of formation of high-mass stars. Modelling of these dense, dusty environments has demonstrated that pumping by infrared radiation can account for the observed masers. Collisions with other molecules in the ambient gas also play a significant role, but have not been well modelled in the past. Here we examine the effects on the maser models of newly available collision rate coefficients for methanol. The new collision data does not alter which transitions become masers in the models, but does influence their brightness and the conditions under which they switch on and off. At gas temperatures above 100 K the effects are broadly consistent with a reduction in the overall collision cross-section. This means, for example, that a slightly higher gas density than identified previously can account for most of the observed masers in W3(OH). We have also examined the effects of including more excited state energy levels in the models, and find that these play a significant role only at dust temperatures above 300 K. An updated list of class II methanol maser candidates is presented.

14 pages, 4 figures, Accepted for publication in MNRAS

References in corpus (6)

• A general catalogue of 6.7 GHz methanol masers. I: data
• A Survey of the Galactic Plane for 6.7-GHz Methanol Masers I: l = 325.0 - 335.0 ; b = -0.53 - 0.53
• Multi-transition study and new detections of class II methanol masers
• Detection of new sources of methanol emission at 107 and 108 GHz with the Mopra telescope
• Discovery of new 19.9-GHz methanol masers in star forming regions
• Search for class II methanol masers at 23.1 GHz

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