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		| Paper: | 
		Spatially-resolved Measurement of Hydrogen Volume Density in the Central Molecular Zone of the Milky Way | 
	 
	
		| Volume: | 
		528, New Horizons in Galactic Center Astronomy and Beyond | 
	 
	
		| Page: | 
		329 | 
	 
	
		| Authors: | 
		Tanaka, K. | 
	 
	
	
		| Abstract: | 
		We present the results of spatially resolved measurement of hydrogen volume density in the CMZ     obtained through excitation study using 13 archival and newly-obtained molecular line data, whee a newly-developed hierarchical parameter inference technique is used to suppress artifacts from the deficiency in simple one-zone LVG analysis.     The main results are:   (1) CMZ clouds are generally affected by shock-waves, as indicated by the spatial correlation between the temperature variation and that in the abundances of shock-tracer molecules.   (2) Statistical discriminant analysis has shown that the parameters that distinguish the clouds with signatures of star formation from quiescent clouds are the virial parameter and volume density. | 
	 
	
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