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		| Paper: | 
		Molecular Gas in the Disk of M 31 | 
	 
	
		| Volume: | 
		396, Formation and Evolution of Galaxy Disks | 
	 
	
		| Page: | 
		51 | 
	 
	
		| Authors: | 
		Brouillet, N.; Braine, J.; Herpin, F.; Rodriguez-Fernandez, N.J.; Muller, S. | 
	 
	
	
		| Abstract: | 
		We present a study of the molecular gas throughout the disk of M 31. From observations with the IRAM 30-m telescope in the HCN and HCO+ lines we have deduced the distribution of the dense gas in the disk of the galaxy and its variation as a function of the galactocentric radius. We have focused on a segment of a spiral arm to compare ISM tracers (CO, H I), star formation tracers (Hα, 24 μm) and the [C II] line emission from ISO observations. [C II] emission is an excellent tracer of star formation and by comparison with photodissociation region models we have estimated the quantity of H I that is the product of H2 dissociation. | 
	 
	
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