A 1 mm SPECTRAL LINE SURVEY TOWARD GLIMPSE EXTENDED GREEN OBJECTS (EGOs)
- Key Laboratory for the Structure and Evolution of Celestial Objects, Yunnan Astronomical Observatory/National Astronomical Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming, 650011 Yunnan Province (China)
- Academia Sinica, Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)
A northern subsample of 89 Spitzer GLIMPSE extended green objects (EGOs), the candidate massive young stellar objects, are surveyed for molecular lines in two 1 GHz ranges: 251.5-252.5 and 260.188-261.188 GHz. A comprehensive catalog of observed molecular line data and spectral plots are presented. Eight molecular species are undoubtedly detected: H{sup 13}CO{sup +}, SiO, SO, CH{sub 3}OH, CH{sub 3}OCH{sub 3}, CH{sub 3}CH{sub 2}CN, HCOOCH{sub 3}, and HN{sup 13}C. The H{sup 13}CO{sup +} 3-2 line is detected in 70 EGOs, among which 37 also show the SiO 6-5 line, demonstrating their association with dense gas and supporting the outflow interpretation of the extended 4.5 {mu}m excess emission. Our major dense gas and outflow tracers (H{sup 13}CO{sup +}, SiO, SO, and CH{sub 3}OH) are combined with our previous survey of {sup 13}CO, {sup 12}CO, and C{sup 18}O 1-0 toward the same sample of EGOs for a multi-line, multi-cloud analysis of linewidth and luminosity correlations. Good log-linear correlations are found among all considered line luminosities, the explanation of which requires a universal similarity of density and thermal structures and probably of shock properties among all EGO clouds. It also requires that the shocks be produced within the natal clouds of the EGOs. Diverse degrees of correlation are found among the linewidths. However, both the linewidth and luminosity correlations tend to progressively worsen across larger cloud subcomponent size scales, depicting the increase of randomness across cloud subcomponent sizes. Moreover, the linewidth correlations among the three isotopic CO 1-0 lines show data scatter as linear functions of the linewidth itself, indicating that the velocity randomness also increases with whole cloud sizes in a regular way.
- OSTI ID:
- 22089884
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 202, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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