EDP Sciences
Free access
Volume 380, Number 2, December III 2001
Page(s) 665 - 672
Section Diffuse matter in space
DOI http://dx.doi.org/10.1051/0004-6361:20011498

A&A 380, 665-672 (2001)
DOI: 10.1051/0004-6361:20011498

A search for massive dense cores with $^\mathsf{13}$CO J = 1-0 line

Y. Wu, J. Wu and J. Wang

Astronomy Department, CAS-PKU Joint Beijing Astrophysics Center, Peking University, Beijing 100871, PR China

(Received 31 January 2001 / Accepted 15 October 2001)

This paper reports 13CO J=1-0 line observations toward 107 IRAS or H2O maser sources with the 13.7 m telescope of the Purple Mountain Observatory (PMO). Parameters of emission components are obtained and the profile characteristics are identified. For all the components, kinematic distances are derived. The bolometric luminosities of the corresponding IRAS sources are calculated for 95 sources, all of which are larger than 103 $L_{\odot}$. We also mapped eight sources. Results show that there are cores in the clouds. The sizes of the cores are about 1~3 pc, much greater and more extensive than those of cores in dark clouds. The hydrogen densities are ~102-103 cm-3. Systematic velocity shifts were found in 3 sources. Every mapped core contains one or more IRAS source. Each core has one and only one IRAS source that satisfies the criteria of ultra compact HII (UC HII) regions. For the cores, 2MASS data are available; dozens of 2MASS sources with different color indices and brightness are found within the core.

Key words: star: formation -- ISM: clouds -- ISM: kinematics and dynamics

Offprint request: Y. Wu, ywu@vega.bac.pku.edu.cn

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