131092 - 84-GHz methanol masers, their relationship to 36-GHz methanol masers, and their molecular environments.pdf (1.86 MB)
84-GHz methanol masers, their relationship to 36-GHz methanol masers, and their molecular environments
journal contributionposted on 2023-05-20, 01:17 authored by Breen, SL, Contreras, Y, Dawson, JR, Simon EllingsenSimon Ellingsen, Voronkov, MA, Tiege McCarthyTiege McCarthy
We present observations of the 36-GHz (4−1 → 30 E) and 84-GHz (5−1 → 40 E) class I methanol maser transitions towards a sample of 94 known class I sites. These observations resulted in 93 and 92 detections in the 84- and 36-GHz transitions. While the majority of the 36-GHz sources have been previously reported, many of the sites are observed in the 84-GHz transition for the first time. The near-simultaneous observations of the two transitions revealed strikingly similar spectral profiles and a mean and median 36- to 84-GHz integrated flux density ratio of 2.6 and 1.4. Alongside the 36- and 84-GHz observations, we included rare class II methanol masers at 37.7, 38.3, 38.5, 86.6, and 86.9 GHz, a number of recombination lines, and thermal molecular transitions. We detect one new site of 86.6- and 86.9-GHz methanol masers, as well as six maser candidates in one or more of 37.7-, 38.3-, 38.5-, 86.6-, and 86.9-GHz methanol maser transitions. We detect a relatively higher rate of HC3N compared to that reported by MALT90 (once the respective detection limits were taken into account), who targeted dense dust clumps, suggesting that the class I methanol maser targets incorporate a relatively higher number of warm protostellar sources. We further find that there are similar relationships between the integrated flux density of both class I transitions with the integrated intensity of HC3N, HNC, HCO+, HNC, SiO, and H13CO+. We suggest that this indicates that the integrated flux densities of the 36- and 84-GHz transitions are closely linked to the available gas volume.
Australian Research Council
Publication titleMonthly Notices of the Royal Astronomical Society
Department/SchoolSchool of Natural Sciences
PublisherBlackwell Publishing Ltd
Place of publication9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg
Rights statementCopyright 2019 The Authors. This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.