Y. Doi

Detection of Sub-TeV Gamma Rays from the Galactic Center Direction by CANGAROO-II

K. Tsuchiya, R. Enomoto, L. T. Ksenofontov, M. Mori, T. Naito, A. Asahara, G. V. Bicknell, R. W. Clay, Y. Doi, P. G. Edwards, S. Gunji, S. Hara, T. Hara, T. Hattori, Sei. Hayashi, C. Itoh, S. Kabuki, F. Kajino, H. Katagiri, A. Kawachi, T. Kifune, H. Kubo, T. Kurihara, R. Kurosaka, J. Kushida Y. Matsubara, Y. Miyashita, Y. Mizumoto, H. Moro, H. Muraishi, Y. Muraki, T. Nakase, D. Nishida, K. Nishijima, M. Ohishi, K. Okumura, J. R. Patterson, R. J. Protheroe, N. Sakamoto, K. Sakurazawa, D. L. Swaby, T. Tanimori, H. Tanimura, G. Thornton, F. Tokanai, T. Uchida, S. Watanabe, T. Yamaoka, S. Yanagita, T. Yoshida, and T. Yoshikoshi

Detection of gamma rays around 1 TeV from RX J0852.0-4622 by CANGAROO-II

We have detected gamma-ray emission at the 6 σ level at energies greater than 500 GeV from the supernova remnant RX J0852.0-4622 (G266.2-1.2) using the CANGAROO-II imaging atmospheric Cerenkov telescope. The flux was 0.12 times that of Crab at 1 TeV. The signal centroid is consistent with the peak of the X-ray emission in the northwest rim of the remnant.

A Search for Sub-TeV Gamma Rays from the Vela Pulsar Region with CANGAROO-III

We made stereoscopic observations of the Vela pulsar region with two of the 10 m diameter CANGAROO-III imaging atmospheric Cerenkov telescopes in 2004 January and February in a search for sub-TeV gamma rays from the pulsar and surrounding regions. We describe the observations, provide a detailed account of the calibration methods, and introduce the improved and bias-free analysis techniques employed for CANGAROO-III data. No evidence of gamma-ray emission is found from either the pulsar position or the previously reported position offset by 013, and the resulting upper limits are a factor of 5 less than the previously reported flux from observations with the CANGAROO-I 3.8 m telescope. Following the recent report by the H.E.S.S. group of TeV gamma-ray emission from the pulsar wind nebula, which is ~05 south of the pulsar position, we examined this region and found supporting evidence for emission extended over ~06.We made stereoscopic observations of the Vela Pulsar region with two of the 10 m diameter CANGAROO-III imaging atmospheric Cherenkov telescopes in January and February, 2004, in a search for sub-TeV gamma-rays from the pulsar and surrounding regions. We describe the observations, provide a detailed account of the calibration methods, and introduce the improved and bias-free analysis techniques employed for CANGAROO-III data. No evidence of gamma-ray emission is found from either the pulsar position or the previously reported position offset by 0.13 degree, and the resulting upper limits are a factor of five less than the previously reported flux from observations with the CANGAROO-I 3.8 m telescope. Following the recent report by the H.E.S.S. group of TeV gamma-ray emission from the Pulsar Wind Nebula, which is

Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope

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Status of the CANGAROO-III project

0.5 degree south of the pulsar position, we examined this region and found supporting evidence for emission extended over

Very high energy gamma-ray observations of the Galactic plane with the CANGAROO-III telescopes

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Recent status of the analyses for stereoscopic observations with the CANGAROO-III telescopes

0.6 degree.

Performance of the Reflector of the CANGAROO-III Imaging Atmospheric Cherenkov Telescope

SS433, located at the center of the supernova remnant W50, is a close proximity binary system consisting of a compact star and a normal star. Jets of material are directed outwards from the vicinity of the compact star symmetrically to the east and west. Non-thermal hard X-ray emission is detected from lobes lying on both sides. Shock accelerated electrons are expected to generate VHE gamma rays through the inverse-Compton process in the lobes. Observations of the western X-ray lobe region of SS433/W50 system have been performed to detect VHE gamma rays using the 10 m CANGAROO-II telescope in August and September, 2001, and July and September, 2002. The total observation times are 85.2 h for ON source, and 80.8 h for OFF source data. No significant excess of VHE gamma rays has been found at three regions of the western X-ray lobe of SS433/W50 system. We have derived 99% confidence level upper limits to the fluxes of gamma rays and ha ve set constraints on the strengths of the magnetic fields ass uming the synchrotron/inverse-Compton model for the wide energy range of photon spectrum from radio to TeV. The derived lower limits are 4.3µG for the center of the brightest X-ray emission region and 6.3µG for the far end from SS433 in the western X-ray lobe. In addition, we suggest that the spot-like X-ray emission may provide a major contribution to the hardest X-ray spectrum in the lobe.