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		| Paper: | 
		Implications of Aging in Young Supernovae | 
	 
	
		| Volume: | 
		342, 1604-2004: Supernovae as Cosmological Lighthouses | 
	 
	
		| Page: | 
		430 | 
	 
	
		| Authors: | 
		Chandra, P.; Ray, A. | 
	 
	
	
		| Abstract: | 
		We present here the combined radio spectrum from the Giant Metrewave Radio Telescope and Very Large Array of type IIb SN 1993J (age 11 years) and a type Ic SN 2003bg (age 1 year). In SN 1993J, we find a break in the spectrum at 4 GHz and associate it with Synchrotron cooling break. Hence, we determine the magnetic field independent of equipartition assumption between relativistic electrons and magnetic energy. We also see a hint of break in the spectrum of SN 2003bg between 22-40 GHz. The spectrum of SN 2003bg is well described by the synchrotron self absorption model. | 
	 
	
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