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A 95 GHz class I methanol maser survey toward glimpse extended green objects (EGOs)
journal contribution
posted on 2023-05-17, 08:10 authored by Chen, X, Simon EllingsenSimon Ellingsen, Shen, ZQ, Titmarsh, AM, Gan, CGWe report the results of a systematic survey for 95 GHz class I methanol masers toward a new sample of 192 massive young stellar object candidates associated with ongoing outflows (known as extended green objects or EGOs) identified from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) survey. The observations were made with the Australia Telescope National Facility (ATNF) Mopra 22 m radio telescope and resulted in the detection of 105 new 95 GHz class I methanol masers. For 92 of the sources our observations provide the first identification of a class I maser transition associated with these objects (i.e., they are new class I methanol maser sources). Our survey proves that there is indeed a high detection rate (55%) of class I methanol masers toward EGOs. Comparison of the GLIMPSE point sources associated with EGOs with and without class I methanol maser detections shows that they have similar mid-IR colors, with the majority meeting the color selection criteria –0.6 < [5.8]-[8.0] < 1.4 and 0.5 < [3.6]-[4.5] < 4.0. Investigations of the Infrared Array Camera and Multiband Imaging Photometer for Spitzer 24 μm colors and the associated millimeter dust clump properties (mass and density) of the EGOs for the sub-samples based on the class of methanol masers they are associated with suggest that the stellar mass range associated with class I methanol masers extends to lower masses than for class II methanol masers, or alternatively class I methanol masers may be associated with more than one evolutionary phase during the formation of a high-mass star.
History
Publication title
The Astrophysical Journal Supplement SeriesVolume
196Article number
9Number
9Pagination
1-28ISSN
0067-0049Department/School
School of Natural SciencesPublisher
Institute of Physics Publishing IncPlace of publication
United StatesRights statement
Copyright 2011 The American Astronomical SocietyRepository Status
- Restricted