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 4. Behaviors of the reduced small/large photon sphere radius as a function of α for five-dimensional Gauss-Bonnet AdS black holes with charge Q = 0 (red line), 0.01(blue line), 0.1(orange line) and 1(green line) at $\tilde{P}=0.98$ : (a) ${\tilde{r}}_{{ps}}$, (b) ${\tilde{r}}_{{pl}}$, (c) ${\rm{\Delta }}{\tilde{r}}_{p}$.