Search for resonances in top anti-top pairs with the ATLAS detector

Four analyses searching for resonant production of top quark pairs using data taken with the ATLAS detector in proton-proton collisions at the CERN Large Hadron Collider at a centre-ofmass energy of 7 TeV are reviewed. Top anti-top pairs decaying in the dileptonic, allhadronic and lepton+jets channels were studied using resolved as well as boosted regimes. Moreover, resonant top+jet production was searched for. Up to 4.7 fb$^{-1}$ of data were analysed and all data were found to be consistent with the Standard Model. Hence, upper limits were set on the production cross-section times branching ratio into top anti-top pairs for a potential resonance, as well as on the minimal mass of such a resonance in narrow and large width benchmark scenarios.