Nuclear modification factor \raa for isolated photons at \snnfive for isolation-cone radii $R=0.2$ (black) and $R=0.4$ (blue). Error bars and boxes are the statistical and systematic uncertainties, respectively. The isolated-photon \raa is compared to that of charged particles~ and charged pions~ from ALICE, and to the ratio of the \zz-boson yield in each centrality class to the 0--90\% class measured by CMS~. The bands correspond to pQCD calculations with JETPHOX for \PbPb collisions (nPDF) for 0--100\% centrality over pp collisions (PDF). The width of each band corresponds to the scale and PDF uncertainties The normalisation uncertainties are represented as a red box centred at unity The solid line in the most peripheral centrality class 70--90\% at \raa = 0.82 corresponds to the HG-PYTHIA model expectation~.