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		| Paper: | 
		Distinguishing Active Galactic Nuclei and Star Formation | 
	 
	
		| Volume: | 
		390, Pathways Through an Eclectic Universe | 
	 
	
		| Page: | 
		283 | 
	 
	
		| Authors: | 
		Groves, B.; Kewley, L. | 
	 
	
	
		| Abstract: | 
		Using the large emission-line galaxy sample from the Sloan Digital Sky Survey we show that star-forming galaxies, Seyferts, and low ionization nuclear emission-line regions (LINERs) form clearly separated branches on the standard optical diagnostic diagrams. We derive a new empirical classification scheme that cleanly separates these emission-line galaxies, using strong optical emission lines. Using this classification, we identify a few distinguishing host galaxy properties in each class, which, along with the emission-line analysis, suggest continuous evolution from one class to another. As a final note, we introduce models of both star-forming galaxies and AGN narrow-line regions that can explain the distribution of galaxies on standard emission-line ratio diagrams and possibly suggest new diagnostics across the emission spectrum. | 
	 
	
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