Please use this identifier to cite or link to this item:
Title: A 12.2 GHz Methanol Maser Survey toward the 6.7 GHz Counterparts Associated with/without UC H ii Regions
Authors: Song, S. -M.
Chen, X.
Shen, Z. -Q.
Li, B.
Yang, K.
Ouyang, X.
Sobolev, A. M.
Zhao, Z.
Li, X. -Q.
Cai, F.
Issue Date: 2022
Publisher: American Astronomical Society
American Astronomical Society
Citation: A 12.2 GHz Methanol Maser Survey toward the 6.7 GHz Counterparts Associated with/without UC H ii Regions / S. -M. Song, X. Chen, Z. -Q. Shen et al. // Astrophysical Journal, Supplement Series. — 2022. — Vol. 258. — Iss. 1. — 19.
Abstract: We report a new survey of the 12.2 GHz Class II methanol masers toward a sample of 367 sources with the 6.7 GHz methanol masers conducted with the Shanghai 65 m Tianma Radio Telescope. This sample has been previously made with observations of the radio continuum emission of UC H ii regions by the VLA. A total of 176 sources were detected with the 12.2 GHz methanol maser, with a detection rate of 48%, including 8 new detections. A lower detection rate (<10%) was determined toward the sources in the Galactic longitude ranges of 60°-180°, revealing that the physical environments from those sources in the Local arm or the tails of Galactic arms do not easily excite the 12.2 GHz masers. In addition, two detections of highly excited-state OH masers at the 13.4 GHz transition were made, one of which is a new detection. Compared to previous surveys, one-third of the detected 12.2 GHz masers show considerable flux variations, implying the possible changes of their physical environments associated with variable radiation fields from their host high-mass young stellar objects. A positive log-log correlation is found between the luminosities of the 6.7 and 12.2 GHz masers in our observed sample, suggesting that both the transition masers have similar excitation conditions. The statistical analysis for the relationships between the methanol maser luminosity and UC H ii region spatial size indicates that the maser luminosities of both the 6.7 and 12.2 GHz transitions have a decreasing trend with the spatial sizes of the associated UC H ii regions, indicating that the Class II methanol masers might fade away with the H ii region evolution. © 2022. The Author(s). Published by the American Astronomical Society.
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85123741947
PURE ID: 29479355
ISSN: 0067-0049
metadata.dc.description.sponsorship: We are grateful for support from the operators of the TMRT during the observations. This work was supported by the National Natural Science Foundation of China (11873002, 11590781, 11903009). X.C. is grateful to the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2019). The work of A.M.S. on the relationship between methanol masers and UC H II regions in Section 4.5 was supported by the Russian Science Foundation (RSF) grant 18-12-00193-P. The other work of A.M.S. was supported by the Russian Ministry of Science and Higher Education, No. FEUZ-2020-0030.
RSCF project card: 18-12-00193
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

Files in This Item:
File Description SizeFormat 
2-s2.0-85123741947.pdf1,43 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.