CANGAROO-III Observations of the 2006 Outburst of PKS2155-304

Y. Sakamoto, K. Nishijima, T. Mizukami, E. Yamazaki, J. Kushida, R. Enomoto, M. Ohishi, G. V. Bicknell, R. W. Clay, P. G. Edwards, S. Gunji, S. Hara, T. Hattori, S. Hayashi, Y. Higashi, K. Inoue, S. Kabuki, F. Kajino, H. Katagiri, A. Kawachi, T. Kifune, R. Kiuchi, H. Kubo, R. Mizuniwa, M. Mori, H. Muraishi, T. Naito, T. Nakamori, S. Nakano, D. Nishida, A. Seki, V. Stamatescu, T. Suzuki, D. L. Swaby, T. Tanimori, G. Thornton, F. Tokanai, K. Tsuchiya, S. Watanabe, Y. Yamada, S. Yanagita, T. Yoshida, T. Yoshikoshi, and Y. Yukawa

(Astrophys. J. in press)
PKS2155-304 between 2006 July 28 (MJD 53944) and August 2, triggered by the H.E.S.S. report that the source was in a high state of TeV gamma-ray emission. A signal was detected at the 4.8σ level in an e ective live time of 25.1 hours during the outburst period. The fluxof Very High Energy gammarays from the CANGAROO-III observations shows the variability on the time scale of less than a few hours. The averaged integral ux above 660 GeV is (1.6+-0.3stat+-0.5syst)×10-11cm-2sec-1 which corresponds to ∼45% of the flux observed from the Crab nebula. Follow-up observations between August 17 (MJD 53964) and 25 indicate the source activity had decreased.