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Newly identified extended green objects (EGOs) from the Spitzer GLIMPSE II survey. II. molecular cloud environments


Chen, X and Gan, C-G and Ellingsen, SP and He, J-H and Shen, Z-Q and Titmarsh, AM, Newly identified extended green objects (EGOs) from the Spitzer GLIMPSE II survey. II. molecular cloud environments, Astrophysical Journal, Supplement Series, 206, (2) Article 22. ISSN 0067-0049 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 The American Astronomical Society

DOI: doi:10.1088/0067-0049/206/2/22


We have undertaken a survey of molecular lines in the 3 mm band toward 57 young stellar objects using the Australia Telescope National Facility Mopra 22 m radio telescope. The target sources were young stellar objects with active outflows (extended green objects (EGOs)) newly identified from the GLIMPSE II survey. We observe a high detection rate (50%) of broad line wing emission in the HNC and CS thermal lines, which combined with the high detection rate of class I methanol masers toward these sources (reported in Paper I) further demonstrates that the GLIMPSE II EGOs are associated with outflows. The physical and kinematic characteristics derived from the 3 mm molecular lines for these newly identified EGOs are consistent with these sources being massive young stellar objects with ongoing outflow activity and rapid accretion. These findings support our previous investigations of the mid-infrared properties of these sources and their association with other star formation tracers (e.g., infrared dark clouds, methanol masers and millimeter dust sources) presented in Paper I. The high detection rate (64%) of the hot core tracer CH3CN reveals that the majority of these new EGOs have evolved to the hot molecular core stage. Comparison of the observed molecular column densities with predictions from hot core chemistry models reveals that the newly identified EGOs from the GLIMPSE II survey are members of the youngest hot core population, with an evolutionary time scale of the order of 103 yr.

Item Details

Item Type:Refereed Article
Keywords:infrared, ISM, jets and outflows, radio lines, stars, formation
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Ellingsen, SP (Professor Simon Ellingsen)
UTAS Author:Titmarsh, AM (Miss Anita Titmarsh)
ID Code:85125
Year Published:2013
Web of Science® Times Cited:24
Deposited By:Mathematics and Physics
Deposited On:2013-06-14
Last Modified:2017-11-03

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