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		| Paper: | 
		Models for "Optically Dark" Gamma-Ray Bursts | 
	 
	
		| Volume: | 
		312, Third Rome Workshop on Gamma-Ray Bursts in the Afterglow Era | 
	 
	
		| Page: | 
		175 | 
	 
	
		| Authors: | 
		Lamb, D.Q. | 
	 
	
	
		| Abstract: | 
		Roughly 65 percent of long gamma-ray bursts (GRBs) are "optically dark"; i.e., no optical afterglow is detected for these bursts. Three explanations of these "optically dark" GRBs have been widely discussed: (1) the optical afterglow is extinguished by dust in the vicinity of the GRB or in the star-forming region in which the GRB occurs; (2) some GRBs have optical afterglows that are intrinsically very faint; and (3) the GRB lies at very high redshift (z > 5), and the optical afterglow is absorbed by neutral hydrogen in the host galaxy and in the intergalactic medium along the line of sight from the burst to us. I briefly review and discuss each of these explanations. | 
	 
	
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