A Spectacular VHE Gamma-Ray Outburst from PKS 2155-304 in 2006 - IN2P3 - Institut national de physique nucléaire et de physique des particules Access content directly
Conference Papers Year : 2007

A Spectacular VHE Gamma-Ray Outburst from PKS 2155-304 in 2006

W. Benbow
  • Function : Author
C. Boisson
L. Costamante
  • Function : Author
O. de Jager
  • Function : Author
G. Dubus
D. Emmanoulopoulos
  • Function : Author
M. Punch
C. Raubenheimer
  • Function : Author
M. Raue
  • Function : Author
S. Wagner


Since 2002 the VHE (>100 GeV) gamma-ray flux of the high-frequency peaked BL Lac PKS 2155-304 has been monitored with the High Energy Stereoscopic System (HESS). An extreme gamma-ray outburst was detected in the early hours of July 28, 2006 (MJD 53944). The average flux above 200 GeV observed during this outburst is ~7 times the flux observed from the Crab Nebula above the same threshold. Peak fluxes are measured with one-minute time scale resolution at more than twice this average value. Variability is seen up to ~600 s in the Fourier power spectrum, and well-resolved bursts varying on time scales of ~200 seconds are observed. There are no strong indications for spectral variability within the data. Assuming the emission region has a size comparable to the Schwarzschild radius of a ~10^9 solar mass black hole, Doppler factors greater than 100 are required to accommodate the observed variability time scales.
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Dates and versions

in2p3-00175788 , version 1 (01-10-2007)


  • HAL Id : in2p3-00175788 , version 1


W. Benbow, C. Boisson, L. Costamante, O. de Jager, G. Dubus, et al.. A Spectacular VHE Gamma-Ray Outburst from PKS 2155-304 in 2006. 30th International Cosmic Ray Conference - ICRC 07, Jul 2007, Merida, Mexico. pp.1081-1084. ⟨in2p3-00175788⟩
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