Detection of the BL Lac object 1ES 1426+428 in the Very High Energy gamma-ray band by the CAT Telescope from 1998-2000

  title={Detection of the BL Lac object 1ES 1426+428 in the Very High Energy gamma-ray band by the CAT Telescope from 1998-2000},
  author={Arache Djannati-Atai and B. Kh{\'e}lifi and Serguei Vorobiov and Robert Bazer-Bachi and Georges Debiais and B. Degrange and P. Espigat and B. Fabre and Gilles Fontaine and Philippe Goret and Christian Gouiff{\`e}s and Conor Masterson and F. Piron and M. Punch and M. Rivoal and L. Rob and J-P. Tavernet},
  journal={Astronomy and Astrophysics},
The BL Lac Object 1ES 1426+428, at a red-shift of $z=0.129$, has been monitored by the Cat telescope from February 1998 to June 2000. The accumulation of 26 h of observations shows a γ -ray signal of 321 events above $250\:{\rm GeV}$ at 5.2 standard deviations, determined using data analysis cuts adapted to a weak, steep-spectrum source. The source emission has an average flux of ${\Phi}_{\rm diff}({400\:{\rm GeV}})=6.73\pm1.27^{\rm stat}\pm1.45^{\rm syst}\times10^{-11}\:{\rm cm^{-2}\:s^{-1… 

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