UNIQUE TeV FLARES OF PKS 2155-304 IN JULY 2006

摘要

The high-frequency-peaked BL Lac PKS 2155-304 is one of the brightest and best-studied VHE gamma-ray sources in the southern hemisphere. Since 2002, the High Energy Stereoscopic System (H. E. S. S.) has monitored this source and found it to be in an unusually high state in July 2006. On the nights of 28 and 30 July, two major outbursts occurred, with peak fluxes similar to 80 times the usual values and well-resolved structures varying on time scales of similar to 200 s. Here, we report on spectral variability studies of VHE data of the first flare and show first results of the H. E. S. S. observations during the second flare night.