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		| Paper: | 
		Spectroscopic Measurements of 15 RGB BL Lac Objects | 
	 
	
		| Volume: | 
		299, High Energy Blazar Astronomy | 
	 
	
		| Page: | 
		309 | 
	 
	
		| Authors: | 
		Pasanen, M.; Nilsson, K.; Takalo, L.O.; Heidt, J. | 
	 
	
	
		| Abstract: | 
		The RASS-Green Bank (RGB) BL Lac sample consists of 127 objects. Out of these, redshifts are known for approximately one-half. We have obtained spectroscopic observations of 15 objects at the Calar Alto 2.2 m telescope. Most of them have optical magnitudes around 18 mag in the R-band. We attempted to determine their redshifts and were successful for two objects (RGB2039+523, z = 0.053 and RGB1811+442, z = 0.337) with any confidence. | 
	 
	
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