Measurement of Wgamma and Zgamma Production at ATLAS

We present studies of W and Z bosons with associated high energy photons produced in pp collisions at sqrt(s) = 7 TeV. The analysis uses 35 pb-1 of data collected by the ATLAS experiment in 2010. The event selection requires W and Z bosons decaying into high pT leptons (electrons or muons) and a photon with ET>15 GeV separated from the lepton(s) by a distance Delta_R(l,photon)> 0.7 in eta-phi space. A total of 95 (97) pp->e nu gamma + X (pp-> mu nu gamma + X) and 25 (23) pp-> e+e- gamma + X (pp-> mu+ mu- gamma + X) event candidates are selected. The kinematic distributions of the leptons and photons and the production cross sections are measured. The data are found to agree with Standard Model next-to-leading-order predictions.