|   | 
				
					
	
		  | 
	 
	
		| Paper: | 
		Galaxies in the First Billion Years: Implications for Reionization and the Star Formation History at z > 6 | 
	 
	
		| Volume: | 
		379, Cosmic Frontiers | 
	 
	
		| Page: | 
		280 | 
	 
	
		| Authors: | 
		Bunker, A.J.; Eyles, L.P.; Chiu, K.; Stanway, E.R.; Ellis, R.S.; Stark, D.P.; McMahon, R.G.; Lacy, M. | 
	 
	
	
		| Abstract: | 
		We discuss the selection of star-forming galaxies at z ~ 6 through the Lyman-break technique. Spitzer imaging implies many of these contain older stellar populations (> 200 Myr) which produce detectable Balmer breaks. The ages and stellar masses (~ 1010M⊙) imply that the star formation rate density at earlier epochs may have been significantly higher than at z ~ 6, and might have played a key role in reionizing the Universe. | 
	 
	
		| 
			
			
		 | 
	 
	
		  | 
	 
 
					 
				 | 
				  |