Cangaroo-III search for gamma rays from SN 1987A and the surrounding field

Abstract

Optical images of SN 1987A show a triple-ring structure. The inner (dust) ring has recently increased in brightness and in the number of hot spots, suggesting that the supernova shock wave has collided with the dense preexisting circumstellar medium, a scenario supported by radio and X-ray observations. Such a shocked environment is widely expected to result in the acceleration of charged particles and the accompanying emission of very high energy gamma-rays. Here we report the results of observations made in 2004 and 2006, yielding upper limits on the TeV gamma-ray flux, which are compared with a theoretical prediction. In addition, we set upper limits on the TeV flux for four high-energy objects which are located within the same field of view of the observation: the superbubble 30 Dor C, the Crab-like pulsar PSR B0540−69, the X-ray binary LMC X-1, and the supernova remnant N157B.