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6.7-GHz methanol maser associated outflows: an evolutionary sequence

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posted on 2023-05-18, 08:52 authored by de Villiers, HM, Chrysostomou, A, Thompson, MA, Urquhart, JS, Breen, SL, Burton, MG, Simon EllingsenSimon Ellingsen, Fuller, GA, Pestalozzi, M, Voronkov, MA, Ward-Thompson, D
We present a continuing study of a sample 44 molecular outflows, observed in 13CO lines, closely associated with 6.7-GHz methanol masers, hence called methanol maser associated outflows (MMAOs). We compare MMAO properties with those of outflows from other surveys in the literature. In general, MMAOs follow similar trends, but show a deficit in number at low masses and momenta, with a corresponding higher fraction at the high end of the distributions. A similar trend is seen for the dynamical time-scales of MMAOs. We argue that the lack of relatively low mass and young flows in MMAOs is due to the inherent selection-bias in the sample, i.e. its direct association with 6.7-GHz methanol masers. This implies that methanol masers must switch on after the onset of outflows (hence accretion), and not before a sufficient abundance of methanol is liberated from icy dust mantles. Consequently the average dynamical age of MMAOs is older than for the general population of molecular outflows. We propose an adjusted evolutionary sequence of outflow and maser occurrence in the hot core phase, where methanol masers turn on after the onset of the outflow phase.

History

Publication title

Monthly Notices of the Royal Astronomical Society

Volume

449

Pagination

119-128

ISSN

0035-8711

Department/School

School of Natural Sciences

Publisher

Oxford University Press

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

Copyright 2015 The Authors

Repository Status

  • Open

Socio-economic Objectives

Expanding knowledge in the physical sciences

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