Radio SEDs of GRB 160131A from 0.8 to 44.8 d. Top left: data together with a BPL (Eq. (3)) at 0.8 d; red points identify the bump and were ignored by the fit. Top right: radio SED at 2.7 d fitted with a BPL. Middle left: data together with an empirical SPL (Eq. (2)) at 5.8 d; red points identify the bump ∼8 GHz and were ignored by the fit. Middle right: radio SED at 12.7 d fitted with a BPL. Bottom: data together with a BPL (Eq. (3)) at 44.8 d. Green dashed lines show the resulting modelling. Filled circles indicate detections, and upside-down triangles indicate 3σ upper limits.