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		| Paper: | 
		Multi-Frequency, Multi-Epoch VLBA Polarization Observations of Mrk501 | 
	 
	
		| Volume: | 
		340, Future Directions in High Resolution Astronomy: The 10th Anniversary of the VLBA | 
	 
	
		| Page: | 
		177 | 
	 
	
		| Authors: | 
		Croke, S.; Charlot, P.; Gabuzda, D.; Sol, H. | 
	 
	
	
		| Abstract: | 
		We have analyzed 1+2+4+6 cm VLBA polarization data for the TeV BL Lac object Mrk501 obtained at three epochs separated by 3—4 weeks in March-April, 1998. These observations show no significant total-intensity or polarization variability over the interval covered by the observations, supporting previous claims that variability in the parsec-scale structure of this source (e.g. motions in its VLBI jet) is modest. The B field structure is complex, and shows a sheath-like structure. The rotation-measure distribution shows evidence for variations across the jet, suggesting the presence of a helical B field associated with the VLBI jet. | 
	 
	
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