$p_{T}^{\text{iso, ch}}$ distribution for narrow clusters with 0.1$< \sigma^{2}_{\text {long, 5}\times\text{5}}< $ 0.3 for $p_{\rm T}>$ 16 GeV/$c$, in pp (bottom left frame) and Pb$-$Pb collisions in two centrality classes, 0$-$10% central (top left frame) and 70$-$90% peripheral (top right frame), with $R=$ 0.2 (black bullets) and $R=$ 0.4 (blue squares), in data (full markers) and simulated PYTHIA 8 $\gamma$$-$jet (open markers), embedded into data in the considered centrality class for the Pb$-$Pb collision case.