Total cluster SFR per unit cluster mass as a function of redshift (left) and as a function of cluster mass (right). Open diamonds and triangles show the integrated total SFR estimated with Hα and IR data, respectively, compiled by Koyama et al. (2010). The red line indicates the cluster mass and, consequently, the ΣSFR/M_Cl range of RX J1257. The dashed line shows the best fit to ΣSFR/M_Cl ~ (1 + z)^α, and the dot-dashed line shows the best fit setting the power index to α = 6.