  Quartic gauge couplings are tested by this study of the production of
$WW\gamma$ and $WZ\gamma$ events in 20.2 fb$^{-1}$ of proton--proton collisions
at a centre-of-mass energy of $\sqrt{s} = 8$ TeV recorded with the ATLAS
detector at the LHC. The final state of $WW\gamma$ events containing an
electron, a muon and a photon is analysed as well as the final states of
$WW\gamma$ and $WZ\gamma$ production containing an electron or a muon, two jets
and a photon. For all final states two different fiducial regions are defined:
one yielding the best sensitivity to the production cross-section of the
process and one optimised for the detection of new physical phenomena. In the
former region, the $WW\gamma$ production cross-section is computed and in both
regions, upper limits on the $WW\gamma$ and $WZ\gamma$ production cross-section
are derived. The results obtained in the second phase space are combined for
the interpretation in the context of anomalous quartic gauge couplings using an
effective field theory.
