Multiwavelength Observations of Mrk 501 in 2008
  The well-studied VHE (E >100 GeV) blazar Mrk 501 was observed between March
and May 2008 as part of an extensive multiwavelength observation campaign
including radio, optical, X-ray and VHE gamma-ray instruments. Mrk 501 was in a
low state of activity during the campaign, with a low VHE flux of about 20% the
Crab Nebula flux. Nevertheless, significant flux variations could be observed
in X-rays as well as $\gamma$-rays. Overall Mrk 501 showed increased
variability when going from radio to gamma-ray energies. The broadband spectral
energy distribution during the two different emission states of the campaign
was well described by a homogeneous one-zone synchrotron self-Compton model.
The high emission state was satisfactorily modeled by increasing the amount of
high energy electrons with respect to the low emission state. This
parameterization is consistent with the energy-dependent variability trend
observed during the campaign.
