Statistical Properties of Molecular Clumps in the Galactic Center 50 km s${}^{-1}$ Molecular Cloud

Abstract

We present the statistical properties of molecular clumps in the Galactic center 50 km s${}^{-1}$ molecular cloud (GCM-0.02-0.07) based on observations of the CS $J=1-0$ emission line with the Nobeyama Millimeter Array. In the cloud, 37 molecular clumps with local thermal equilibrium (LTE) masses of $2\times 10^2-6\times 10^3{M}_{\odot }$ were identified by using the {\it clumpfind} algorithm. The velocity widths of the molecular clumps are about five-fold those of Galactic disk molecular clouds with the same radius. The virial-theorem masses are three-fold the LTE masses. The mass and size spectra can be described by power laws of $dN/dM\propto M^{-2.6\pm 0.1}$ ($M\gtrsim 900M_{\odot }$) and $dN/dR\propto R^{-5.9\pm 0.3}$ ($R\gtrsim 0.35$ pc), respectively. The statistical properties of the region interacting with the Sgr A East shell and those of the non-interacting part of the cloud are significantly different. The interaction probably makes the mass function steeper, from $dN/dM\propto M^{-2.0\pm 0.1}$ in the non-interacting part to $dN/dM\propto M^{-4.0\pm 0.2}$ in the interacting region. On the other hand, the interaction presumably truncates the size spectrum on the larger side of $R\sim 0.4$ pc.

16 pages, 5 figures, accepted for publication in PASJ

References in corpus (7)

• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• The Perils of Clumpfind: The Mass Spectrum of Sub-structures in Molecular Clouds
• The Bolocam Galactic Plane Survey IV: 1.1 and 0.35 mm Dust Continuum Emission in the Galactic Center Region
• Properties of Active Galaxies Deduced from H I Observations
• Very Large Array Observations of Galactic Center OH 1720 MHz Masers in Sagittarius A East and in the Circumnuclear Disk
• A C${}^{18}$O study of the origin of the power-law nature in the IMF
• Massive Star Formation of the Sgr A East HII Regions Near the Galactic Center

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