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		| Paper: | 
		3C 66A: Synchrotron Radiation Strength Variation in 2003 | 
	 
	
		| Volume: | 
		360, AGN Variability from X-Rays to Radio Waves | 
	 
	
		| Page: | 
		181 | 
	 
	
		| Authors: | 
		Efimov, Y.S.; Primak, N.V. | 
	 
	
	
		| Abstract: | 
		The BL Lac-type object 3C 66A was observed at the Crimean Astrophysical Observatory from February to December 2003 in the framework of the international program OJ-94. Photopolarimetric observations were carried out with a 125 cm telescope in the UBVRI bands. In all observations the spectral energy distribution is well represented by a power-law spectrum Fv with a spectral index α (Fv ~ v−α). The spectral energy distribution became flatter (α decreased from 1.47 to ~1.1) and the degree of polarization fell (from 15% to ~ 2%) between February and December, when the brightness of the object increased by ~ 1 magnitude. These effects may be due to decreasing magnetic field strength in the jet of 3C 66A. | 
	 
	
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