Universität zu Köln

Yuan, Jinghua ORCID: 0000-0001-8060-3538, Wu, Yuefang, Liu, Tie ORCID: 0000-0002-5286-2564, Zhang, Tianwei, Li, Jin Zeng, Liu, Hong-Li, Meng, Fanyi, Chen, Ping ORCID: 0000-0003-0853-6427, Hu, Runjie and Wang, Ke ORCID: 0000-0002-7237-3856 (2016). DENSE GAS IN MOLECULAR CORES ASSOCIATED WITH PLANCK GALACTIC COLD CLUMPS. Astrophys. J., 820 (1). BRISTOL: IOP PUBLISHING LTD. ISSN 1538-4357

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Abstract

We present the first survey of dense gas toward Planck Galactic Cold Clumps (PGCCs). Observations in the J = 1-0 transitions of HCO+ and HCN toward 621 molecular cores associated with PGCCs were performed using the Purple Mountain Observatory's 13.7 m telescope. Among them, 250 sources were detected, including 230 cores detected in HCO+. and 158 in HCN. Spectra of the J = 1-0 transitions from (CO)-C-12, (CO)-C-13, and (CO)-O-18 at the centers of the 250 cores were extracted from previous mapping observations to construct a multi-line data set. The significantly low detection rate of asymmetric double-peaked profiles, together with the good consistency among central velocities of CO, HCO+, and HCN spectra, suggests that the CO-selected Planck cores are more quiescent than classical star-forming regions. The small difference between line widths of (CO)-O-18. and HCN indicates that the inner regions of CO-selected Planck cores are no more turbulent than the exterior. The velocity-integrated intensities and abundances of HCO+ are positively correlated with those of HCN, suggesting that these two species are well coupled and chemically connected. The detected abundances of both HCO+ and HCN are significantly lower than values in other low- to high-mass star-forming regions. The low abundances may be due to beam dilution. On the basis of an inspection of the parameters given in the PGCC catalog, we suggest that there may be about 1000 PGCC objects that have a sufficient reservoir of dense gas to form stars.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Yuan, Jinghua UNSPECIFIED orcid.org/0000-0001-8060-3538 UNSPECIFIED Wu, Yuefang UNSPECIFIED UNSPECIFIED UNSPECIFIED Liu, Tie UNSPECIFIED orcid.org/0000-0002-5286-2564 UNSPECIFIED Zhang, Tianwei UNSPECIFIED UNSPECIFIED UNSPECIFIED Li, Jin Zeng UNSPECIFIED UNSPECIFIED UNSPECIFIED Liu, Hong-Li UNSPECIFIED UNSPECIFIED UNSPECIFIED Meng, Fanyi UNSPECIFIED UNSPECIFIED UNSPECIFIED Chen, Ping UNSPECIFIED orcid.org/0000-0003-0853-6427 UNSPECIFIED Hu, Runjie UNSPECIFIED UNSPECIFIED UNSPECIFIED Wang, Ke UNSPECIFIED orcid.org/0000-0002-7237-3856 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-281157
DOI:	10.3847/0004-637X/820/1/37
Journal or Publication Title:	Astrophys. J.
Volume:	820
Number:	1
Date:	2016
Publisher:	IOP PUBLISHING LTD
Place of Publication:	BRISTOL
ISSN:	1538-4357
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language INFRARED DARK CLOUDS; STAR-FORMATION; PRESTELLAR CORES; HCN; EMISSION; HERSCHEL; INFLOW; LINE; ABUNDANCES; CHEMISTRY Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/28115