afterglowpy light curves for top-hat jets with θ_jet = 10° (lines). Observing angles θ_obs, isotropic-equivalent kinetic energy and interstellar medium (ISM) density values are given in the legend (bottom panel). We assume d_L ≈ 4.7 Gpc (shaded regions for the distance uncertainty), p = 2.5, and ε_e = ϵ_B = 0.1. Red curves show GW170817 and a GW170817-like afterglow with enhanced ISM density. Top: gray triangles mark VLA 5σ limits at epochs E1–E5, and black symbols show variable field sources (Table 2) as well as EP/X3. Center: symbols mark optical upper limits from follow-up telescopes (see legend). Bottom: symbols mark the candidate X-ray counterpart EP/X3 (see text).