Survey of the Star-Formation Regions Associated with Infrared Sources Observed in the J = 1-0 Line of the CO Molecule and Its Isotopes. Results of Observations Performed in the C super(18)O(J = 1-0) Line

• Published in: Radiophysics and quantum electronics Vol. 48; no. 7; pp. 491 - 499
• Main Authors: Troitsky, N R, Pirogov, LE, Zinchenko, I I, Yang, J
• Format: Journal Article
• Language: English
• Published: 01.07.2005
• Subjects: Carbon monoxide; China; Density; Emission; Estimates; Infrared; Local thermodynamic equilibrium; Maxima; Mountains
• ISSN: 0033-8443; 1573-9120
• DOI: 10.1007/s11141-005-0093-7

We present results of observations of 23 compact cores of molecular clouds associated with IRAS " cold" infrared sources. The observations were performed in the J = 1-0 line of the C super(18)O molecule on a 13.7-meter radio telescope of the Purple Mountain Observatory, China. The C super(18)O (J = 1-0) line was detected in the emission of 21 objects. Column densities of the C super(18)O and H sub(2) molecules towards the maximum of integral intensity of the C super(18)O emission were estimated in the approximation of local thermodynamic equilibrium and amounted to (2.5-10.4) . 10 super(15)cm super(-2) and (1.5-6.1) . 10 super(22) cm super(-2), respectively. The kinetic temperatures determined for these maxima from the CO lines vary from 14 to 45 K. For six objects, whose mapping has been almost completed, the dimensions of the C super(18)O emission regions are estimated to range from 0.5 to 1.2 pc. The masses of these objects lie in the range of (390-1750) M sub() and are close to the estimates following from the virial theorem. The range of average densities of the objects is (0.3-1.4) . 10 super(4) cm super(-3).