Same as the left panel of Fig. 3 but without considering the difference in exposure time of the supercluster members and isolated clusters. The y-axis is rescaled by the radius to reduce the dynamic range of the plot and improve the visibility of the difference between the two samples. The median electron density profile of supercluster members (blue) shows an apparently lower concentration than that of the isolated clusters (yellow). However, this trend should not be simply interpreted as the signal of HAB. It is mostly caused by the fact that supercluster members are located in areas with higher survey depths, where low-concentration clusters have a higher probability of being detected. This plot demonstrates the importance of correcting for selection effects in the analysis of HAB.