More than forty gamma-ray sources have been detected by atmospheric Cherenkov telescopes at TeV energies. However, no cluster of galaxies have been proved to be a TeV gamma-ray emitter until now, though there are many theoretical predictions on the possible gamma-ray fluxes from these gigantic objects assuming various emission mechanisms. We have observed a couple of clusters of galaxies in the southern sky with the CANGAROO-III atmospheric Cherenkov telescope system in 2005-2006, and preliminary results on the analysis to search for gamma-ray signature are reported.

CANGAROO-III collaboration

Proceedings of the 30th International Cosmic Ray Conference; Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.); Universidad Nacional Autónoma de México, Mexico City, Mexico, 2008; Vol. 3 (OG part 2), pages 1005-1008