van den Heever, SP, van der Walt, DJ, Pittard, JM orcid.org/0000-0003-2244-5070 et al. (1 more author) (2019) Periodic methanol masers: from a colliding wind binary (CWB) perspective. Monthly Notices of the Royal Astronomical Society, 485 (2). pp. 2759-2771. ISSN 0035-8711
Abstract
Since the discovery of periodic class II methanol masers at 6.7 and 12.2 GHz associated with high-mass star formation regions (HMSFRs), a number of possible driving mechanisms have been proposed to explain this phenomenon. Here, we apply a more realistic treatment of the original colliding wind binary (CWB) model explanation to investigate to what extent it can describe the flare profiles of the periodic methanol masers. It was found that the CWB hypothesis is feasible from an energetics standpoint, because the emission from the shocked gas does cause an outward shift of the position of the ionization front (IF). This confirms that the energy budget available from the shocked gas is enough to be the driving force behind the CWB model. The CWB model describes the light curve of the 1.25 km s−1 12.2 GHz velocity feature of G9.62 + 0.20E very well over 4000 d. The quiescent state flux density of the 1.25 km s−1 velocity feature can also be described very well by the time-dependent change in electron density (ne). The CWB model also describes the other periodic methanol masers, G22.357 + 0.066, G37.55 + 0.20, and G45.473 + 0.134, which have similar light curves, very well. This strongly suggests that these periodic methanol masers can be described by the time-dependent change in the free–free emission from some part of the background H II region against which the masers are projected.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019, The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. All rights reserved. |
Keywords: | hydrodynamics; masers; H II regions; ISM: molecules; radio lines: ISM; X-rays: binaries |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Funding Information: | Funder Grant number Science & Technology Facilities Council (STFC) ST/L000628/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 30 Oct 2019 16:33 |
Last Modified: | 30 Oct 2019 16:33 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Identification Number: | 10.1093/mnras/stz576 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:152747 |