Nuclear modification factor $R_{\rm AA}$ for isolated photons measured by ALICE for isolation-cone radii $R=$ 0.2 and $R=$ 0.4 and CMS [38] for isolation-cone radius $R=$ 0.4 at $\sqrt{s_{\rm NN}}=$ 5.02 TeV and for four centrality classes. Error bars and boxes are the statistical and systematic uncertainties, respectively. The solid line in the peripheral centrality class 50$-$90% at $R_{\rm AA}=$ 0.91, is the result of the HG-PYTHIA model [41]. The ALICE normalisation uncertainties are represented as a red box centred at unity. For CMS, the normalisation uncertainties are displayed as a violet box for the integrated luminosity and a green box for the nuclear overlap function $\langle T_{\rm AA}\rangle=\langle N_{\rm coll} \rangle/ \sigma_{\rm NN}^{\rm INEL}$.