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		| Paper: | 
		A Spectroscopic Study of a z = 1.6 Galaxy Overdensity in the GMASS Field | 
	 
	
		| Volume: | 
		399, Panoramic Views of Galaxy Formation and Evolution | 
	 
	
		| Page: | 
		332 | 
	 
	
		| Authors: | 
		Kurk, J.; Cimatti, A.; Zamorani, G.; Halliday, C.; Mignoli, M.; Pozzetti, L.; Daddi, E.; Rosati, P.; Dickinson, M.; Bolzonella, M.; Cassata, P.; Renzini, A.; Franceschini, A.; Rodighiero, G.; Berta, S. | 
	 
	
	
		| Abstract: | 
		The Galaxy Mass Assembly ultra-deep Spectroscopic Survey samples a part of the CDFS to unprecedented depth. The resulting distribution of 150 z > 1.4 redshifts reveals a significant peak at z = 1.6, part of a larger overdensity found at this redshift. The 42 spectroscopic members of this structure, called Cl 0332-2742, form an overdensity in redshift of a factor 11±3 and have a velocity dispersion of 450 kms−1. We derive a total mass for Cl 0332-2742 of ∼ 7 × 1014 M⊙. The colours of its early-type galaxies are consistent with a theoretical red sequence of galaxies with stars formed at z = 3.0. In addition, there are more massive, passive and older, but less star forming galaxies in CL 0332-2742 than in the field. We conclude that this structure is a cluster under assembly at z = 1.6. | 
	 
	
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