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PKS 2155-304 - a source of VHE gamma-rays

P. M. Chadwick·K. Lyons·T. J. L. McComb·S. McQueen·K. J. Orford·J. L. Osborne·S. M. Rayner·S. E. Shaw·K. E. Turver·G. J. Wieczorek
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Abstract

The close X-ray selected BL Lac PKS 2155--304 has been observed using the University of Durham Mark 6 very high energy (VHE) gamma ray telescope during 1996 September/October/November and 1997 October/November. VHE gamma rays with energy > 300 GeV were detected with a time-averaged integral flux of (4.2 +/- 0.7 (stat) +/- 2.0 (sys)) x 10^-11 cm^-2 s^-1. There is evidence for VHE gamma ray emission during our observations in 1996 September and 1997 October/November. The strongest emission was detected in 1997 November, when the object was producing the largest flux ever recorded in high-energy X-rays and was detected in > 100 MeV gamma-rays. The VHE and X-ray fluxes are correlated.

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P. M. Chadwick, K. Lyons, T. J. L. McComb, S. McQueen, K. J. Orford, J. L. Osborne, S. M. Rayner, S. E. Shaw, K. E. Turver, G. J. Wieczorek. 1998-12-07. PKS 2155-304 - a source of VHE gamma-rays. https://doi.org/10.1016/s0927-6505(99)00039-0

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