The intrinsic GRB rate dN_GRB/dz. The number of (on-axis + off-axis) GRBs per year on the sky in Eq. (28), as a function of redshift. We set f_∗ = 0.001, f_GRB = 0.01 and v_wind = 100      km   s^-1 for this plot. Salpeter IMF, dashed black line, Gaussian IMF, dotted black line, for Pop III.2; and Salpeter IMF, dashed blue line, Gaussian IMF, dotted blue line, for Pop III.1.