Photon and photon+jet production with the ATLAS detector

Isolated prompt photons provide a direct probe of short- distance physics, complementary to that provided by measurements of jets or vector-bosons and are sensitive to the gluon density of the proton. The inclusive prompt photon cross sections have been measured by the ATLAS collaboration at various centre-of-mass energies of pp collisions over a wide range of transverse momenta. These experimental results are reported in different fiducial regions covering a wide acceptance and are compared to next-to-leading order QCD calculations with different models of the parton content of the proton. The diphoton and photon+jet system cross sections have also been measured as a function of several kinematic variables.