First Multi-wavelength Campaign on the Gamma-ray-loud Active Galaxy IC
  310
  The extragalactic VHE gamma-ray sky is rich in blazars. These are jetted
active galactic nuclei viewed at a small angle to the line-of-sight. Only a
handful of objects viewed at a larger angle are known so far to emit above 100
GeV. Multi-wavelength studies of such objects up to the highest energies
provide new insights into the particle and radiation processes of active
galactic nuclei. We report the results from the first multi-wavelength campaign
observing the TeV detected nucleus of the active galaxy IC 310, whose jet is
observed at a moderate viewing angle of 10 deg - 20 deg. The multi-instrument
campaign was conducted between 2012 Nov. and 2013 Jan., and involved
observations with MAGIC, Fermi, INTEGRAL, Swift, OVRO, MOJAVE and EVN. These
observations were complemented with archival data from the AllWISE and 2MASS
catalogs. A one-zone synchrotron self-Compton model was applied to describe the
broad-band spectral energy distribution. IC 310 showed an extraordinary TeV
flare at the beginning of the campaign, followed by a low, but still detectable
TeV flux. Compared to previous measurements, the spectral shape was found to be
steeper during the low emission state. Simultaneous observations in the soft
X-ray band showed an enhanced energy flux state and a harder-when-brighter
spectral shape behaviour. No strong correlated flux variability was found in
other frequency regimes. The broad-band spectral energy distribution obtained
from these observations supports the hypothesis of a double-hump structure. The
harder-when-brighter trend in the X-ray and VHE emission is consistent with the
behaviour expected from a synchrotron self-Compton scenario. The
contemporaneous broad-band spectral energy distribution is well described with
a one-zone synchrotron self-Compton model using parameters that are comparable
to those found for other gamma-ray-emitting misaligned blazars.
