Left: 3 GHz light curve of afterglow from structured jet at distance D = 42 Mpc, with sharp power-law structure (a = 4.5, b = 2.5; see Eqs. (1)–(2)), viewing angle θ_v = 22°, external density n = 3 × 10⁻³ cm⁻³, core jet with θ_j = 4°, Γ_c = 100, E_iso, c = 2 × 10⁵² erg, and with microphysics parameters p = 2.2, ϵ_e = 0.1 and ϵ_B = 10⁻⁴. The radio observations of GW170817 are also plotted and are compiled from Hallinan et al. (2017), Alexander et al. (2018), Margutti et al. (2018), Mooley et al. (2018a,b), Dobie et al. (2018). The respective contributions of the core jet (θ ≤ θ_j), the sheath and the total are plotted in dashed, dotted and solid red lines. The flux of the core jet computed with the simplified treatment described by Eq. (4) is also plotted in dashed blue line for comparison. Bottom right: peak flux of same structured jet as function of viewing angle θ_v (solid red line), peak flux of light curve from core jet only (dashed red line) or from sheath only (dotted red line), and peak flux of core jet as computed using scaling law in Eq. (6) (thin black line). Upper right: ratio of peak flux from whole outflow (core jet+sheath) to that of core jet only.