Constraints on an effective Lagrangian from the combined $H\to ZZ^*\to 4\ell$ and $H\to\gamma\gamma$ channels using 36.1 fb$^{-1}$ of $\sqrt{s}=$ 13 TeV $pp$ collision data collected with the ATLAS detector

Six parameters of an effective field theory are constrained using the combined $H\to\gamma\gamma$ and $H\to ZZ^*\to 4\ell$ channels, based on 36.1 fb$^{-1}$ of proton-proton collision data collected by the ATLAS experiment at the LHC at $\sqrt{s}=$ 13 TeV. The parameters are sensitive to modifications of the Higgs boson couplings to strong and electroweak gauge bosons, and to the top quark. The most stringent constraints are those on the effective couplings to photons and to gluons.