Confidence level of the excess in gas mass concentration, c_gas. The histogram shows the distribution of δc_gas defined as c_gas, S1/c_gas, S2 − 1 when randomly dividing the clusters into two subsamples (S1 and S2) and repeating 1000 times. The dashed lines indicate the δc_gas when the clusters are divided into supercluster members and isolated clusters. The results are shown for different overdensity ratios in the identification of superclusters. The shaded area represents 1σ uncertainty. The cyan and purple lines correspond to 1.6σ for f = 10 and 2.0σ for f = 50, respectively.