The H.E.S.S. extragalactic sky
  The H.E.S.S. Cherenkov telescope array, located on the southern hemisphere in
Namibia, studies very high energy (VHE; E>100 GeV) gamma-ray emission from
astrophysical objects. During its successful operations since 2002 more than 80
galactic and extra-galactic gamma-ray sources have been discovered. H.E.S.S.
devotes over 400 hours of observation time per year to the observation of
extra-galactic sources resulting in the discovery of several new sources,
mostly AGNs, and in exciting physics results e.g. the discovery of very rapid
variability during extreme flux outbursts of PKS 2155-304, stringent limits on
the density of the extragalactic background light (EBL) in the near-infrared
derived from the energy spectra of distant sources, or the discovery of
short-term variability in the VHE emission from the radio galaxy M 87. With the
recent launch of the Fermi satellite in 2008 new insights into the physics of
AGNs at GeV energies emerged, leading to the discovery of several new
extragalactic VHE sources. Multi-wavelength observations prove to be a powerful
tool to investigate the production mechanism for VHE emission in AGNs. Here,
new results from H.E.S.S. observations of extragalactic sources will be
presented and their implications for the physics of these sources will be
discussed.
