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Title: NEWLY IDENTIFIED EXTENDED GREEN OBJECTS (EGOs) FROM THE SPITZER GLIMPSE II SURVEY. II. MOLECULAR CLOUD ENVIRONMENTS

Abstract

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 CH{sub 3}CN reveals that the majority of these new EGOs have evolved to the hot molecular core stage. Comparison of the observedmore » 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 10{sup 3} yr.« less

Authors:
; ;  [1]; ;  [2]
  1. Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China)
  2. School of Mathematics and Physics, University of Tasmania, Hobart, Tasmania (Australia)
Publication Date:
OSTI Identifier:
22118759
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal, Supplement Series
Additional Journal Information:
Journal Volume: 206; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0067-0049
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACETONITRILE; ASTROPHYSICS; COMPARATIVE EVALUATIONS; COSMIC DUST; DETECTION; INTERMEDIATE INFRARED RADIATION; JETS; MASERS; METHANOL; PHOTON EMISSION; RADIO TELESCOPES; RADIOASTRONOMY; STARS

Citation Formats

Xi, Chen, Conggui, Gan, Zhiqiang, Shen, Ellingsen, Simon P., Titmarsh, Anita, and He Jinhua, E-mail: chenxi@shao.ac.cn. NEWLY IDENTIFIED EXTENDED GREEN OBJECTS (EGOs) FROM THE SPITZER GLIMPSE II SURVEY. II. MOLECULAR CLOUD ENVIRONMENTS. United States: N. p., 2013. Web. doi:10.1088/0067-0049/206/2/22.
Xi, Chen, Conggui, Gan, Zhiqiang, Shen, Ellingsen, Simon P., Titmarsh, Anita, & He Jinhua, E-mail: chenxi@shao.ac.cn. NEWLY IDENTIFIED EXTENDED GREEN OBJECTS (EGOs) FROM THE SPITZER GLIMPSE II SURVEY. II. MOLECULAR CLOUD ENVIRONMENTS. United States. https://doi.org/10.1088/0067-0049/206/2/22
Xi, Chen, Conggui, Gan, Zhiqiang, Shen, Ellingsen, Simon P., Titmarsh, Anita, and He Jinhua, E-mail: chenxi@shao.ac.cn. 2013. "NEWLY IDENTIFIED EXTENDED GREEN OBJECTS (EGOs) FROM THE SPITZER GLIMPSE II SURVEY. II. MOLECULAR CLOUD ENVIRONMENTS". United States. https://doi.org/10.1088/0067-0049/206/2/22.
@article{osti_22118759,
title = {NEWLY IDENTIFIED EXTENDED GREEN OBJECTS (EGOs) FROM THE SPITZER GLIMPSE II SURVEY. II. MOLECULAR CLOUD ENVIRONMENTS},
author = {Xi, Chen and Conggui, Gan and Zhiqiang, Shen and Ellingsen, Simon P. and Titmarsh, Anita and He Jinhua, E-mail: chenxi@shao.ac.cn},
abstractNote = {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 CH{sub 3}CN 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 10{sup 3} yr.},
doi = {10.1088/0067-0049/206/2/22},
url = {https://www.osti.gov/biblio/22118759}, journal = {Astrophysical Journal, Supplement Series},
issn = {0067-0049},
number = 2,
volume = 206,
place = {United States},
year = {Sat Jun 01 00:00:00 EDT 2013},
month = {Sat Jun 01 00:00:00 EDT 2013}
}