Dense Molecular Clouds in the Galactic Center Region. II. Statistical Properties of the Galactic Center Molecular Clouds

Abstract

We present statistical properties of molecular clouds based on the Galactic center region survey in CS J = 1-0 with the 45 m radio telescope of the Nobeyama Radio Observatory. We identified 159 molecular cloud clumps from the survey data. We found that the velocity widths of the Galactic center molecular clumps are about 5 times larger than those of the Galactic disk molecular clouds with the same radius. We estimated the virial theorem masses and the LTE masses of the identified clumps. The virial-theorem masses are 1 order of magnitude larger than the LTE masses. We obtain the mass and size spectra for the Galactic center molecular clumps. The mass spectrum is dN/dM ∝ M-1.6±0.1 (M 1.0 × 104 M☉). The spectral index was approximately equal to the values obtained in the Galactic disk regions, although the statistical relations, such as the line width-size relation, for the Galactic center clouds are much different from those for the disk clouds. The size spectrum is dN/dR ∝ R-4.0±0.4 (R 3.3 pc). The spectral index is consistent with those for the disk clouds.