SFR surface densities Σ_SFR of DLAs from the spectral stacks. Limits on the SFR surface densities derived from the composite images are shown as horizontal hatched blue bars (Fumagalli et al. 2015). The grey shaded region show the Σ_SFR detected in the outskirts of LBGs Rafelski et al. (2011), and the blue shaded region shows the ESDLA (N(H I) > 10^21.7 cm⁻²) (Noterdaeme et al. 2014). The dotted black line shows where the extrapolation of the local SF law. Our results shows log N(H I/cm⁻²)≥21 to 22.35 with range of f_esc, 0.05 and 0.15 showing dashed (red dashed) region.