Orateur
Description
Summary
The third generation of Very High Energy (VHE; E>100 GeV) gamma-ray
telescopes (e.g. HESS, VERITAS & MAGIC)
are an order of magnitude more sensitive than their predecessors. Over
the past four years observations with these instruments
have increased the catalog of VHE emitters to more than 70 sources, of
which 22 are extragalactic.
While only limited variability is found from the 15 newly discovered VHE
blazars, the more sensitive studies of
the 7 previously known extragalactic VHE emitters (6 blazars & the
radio-galaxy M 87) have yielded unprecedented
results. Recent highlights include the discovery of minute-scale VHE
flux variability, significant VHE spectral changes on
sub-hour time-scales, and strong correlations of these rapid VHE
variations (flux & spectrum) with those
simultaneously observed at X-ray energies. A summary of the variability
properties of VHE blazars will be presented.
