Photon sphere and phase transition of d-dimensional (d ≥ 5) charged Gauss-Bonnet AdS black holes

Shan-Zhong Han,Jie Jiang,Ming Zhang,Wen-Biao Liu

Figure 3. Behaviors of the reduced small/large photon sphere radius as a function of Q for five-dimensional Gauss-Bonnet AdS black holes with coefficient α = 0.01(blue line), 0.1(orange line) and 1(green line) at $\tilde{P}=0.98$: (a) ${\tilde{r}}_{{\rm{ps}}}$, (b) ${\tilde{r}}_{{\rm{pl}}}$, (c) ${\rm{\Delta }}{\tilde{r}}_{p}$.