Measurements of $t\overline{t}$+X using the ATLAS detector

The large centre-of-mass energy available at the Large Hadron Collider (LHC) allowsfor the copious production of top quark pairs in association with other final stateparticles at high transverse momenta.Several final state observables that are sensitive to additional radiation in topanti-top quark final states has been measured by the ATLAS experiment.The production of top quark pair in association with $W$ and $Z$ bosons or with aphoton have been also measured.Analyses probing the top pair production with additional QCD radiation include themultiplicity of jets for various transverse momentum thresholds in the 13 TeV data.These measurements are compared to modern Monte Carlo generators based on NLO QCDmatrix element or LO multi-leg matrix elements,and the results are consistent with the standard model predictions within the uncertainties.