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 $\langle T_{\rm AA}\rangle=\langle N_{\rm coll} \rangle / \sigma_{\rm NN}^{\rm INEL}$.