Constraints on Extragalactic Background Light from Cherenkov telescopes: status and perspectives for the next 5 years

Magic Γ-ray Observations of Distant Agn and a Study of Source Variability and the Extragalactic Background Light Using Fermi and Air Cherenkov Telescopes

Exploring the Gamma Ray Horizon with the next Generation of Gamma Ray Telescopes. Part 1: Theoretical Predictions

The physics potential of the next generation of Gamma Ray Telescopes in exploring the Gamma Ray Horizon is discussed. It is shown that the reduction in the Gamma Ray detection threshold might open the window to use precise determinations of the Gamma Ray Horizon as a function of the redshift to either put strong constraints on the Extragalactic Background Light modeling or to obtain relevant in...

Discovery of Very High Energy gamma-ray emission from the distant BL Lac object H2356-309 with the H.E.S.S. Cherenkov Telescopes

The H.E.S.S.(High Energy Stereoscopic System) array of imaging Cherenkov telescopes has recently discovered the most distant extra-galactic Very High Energy (VHE, E>160GeV) gamma-ray emitters. Located at a redshift of z=0.165, the extreme synchrotron BL Lac object H2356-309 was observed with H.E.S.S. in a simultaneous multi-wavelength campaign including radio, optical and X-ray observatories. U...

Multi-wavelength Observations of the TeV Blazars Mkn 421, 1ES1959+650, and H1426+428 with the HEGRA Cherenkov Telescopes and the RXTE X-ray Satellite

Recent results obtained with the HEGRA system of imaging Cherenkov telescopes on the TeV emission of the Blazars Mkn 421 (z = 0.030), 1ES1959+650 (z = 0.047), and H1426+428 (z = 0.129) are reported. For Mkn 421, a close connection of the average flux level and spectral shape has been observed during the periods of increased activity in the years 2000 and 2001. Simultaneously taken data with the...

The HEGRA Experiment Status and Recent Results

A report is given on the status and recent results from the HEGRA imaging atmospheric Cherenkov telescopes (IACT) concerning Mrk 501 and GRS 1915+105 and on recent results from the HEGRA arrays concerning galactic and extragalactic γ-sources, counterparts of TeV Gamma-Ray-Bursts, cosmic ray anisotropies, energy spectrum and composition of primary cosmic rays. The report summarizes the presentat...