137052 - 36 GHz methanol lines from nearby galaxies.pdf (186.29 kB)
Variability in extragalactic class I methanol masers: new maser components towards NGC 4945 and NGC 253
journal contribution
posted on 2023-05-20, 10:14 authored by Tiege McCarthyTiege McCarthy, Simon EllingsenSimon Ellingsen, Breen, SL, Voronkov, MA, Chen, X, Qiao, H-hWe have used the Australia Telescope Compact Array (ATCA) to make new observations of the 36.2-GHz (4−1 → 30E) methanol transition towards NGC 4945 and NGC 253. These observations have revealed the presence of new maser components towards these galaxies, and have provided the first clear evidence for variability in extragalactic class I methanol masers. Alongside the new observations of NGC 4945 and NGC 253, we present the results of recent 36.2-GHz methanol maser searches towards 12 galaxies, placing upper limits on the emission from the 36.2-GHz class I transition and the 37.7-GHz (72 → 81E) class II maser line towards these sources. Flux density values for the 7-mm continuum emission towards these sources are also reported where applicable. A re-analysis of the published 36.2-GHz methanol observations of Arp 220 undertaken as part of the search revealed some issues with previous imaging procedures. The re-analysis, combined with non-detections in independent follow-up observations, suggests that there is no 36.2-GHz methanol emission towards Arp 220 stronger than 3.5 mJy in a 10 km s−1 channel (5σ upper limit).
History
Publication title
Monthly Notices of the Royal Astronomical SocietyVolume
491Issue
4Pagination
4642-4655ISSN
0035-8711Department/School
School of Natural SciencesPublisher
Blackwell Publishing LtdPlace of publication
9600 Garsington Rd, Oxford, England, Oxon, Ox4 2DgRights statement
Copyright 2020 P.K. Humire et al. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/Repository Status
- Open