Distributions in viewing angle of the afterglows detectable in the radio band at three times the VLA threshold (45 μJy) following a GW-triggered kilonova detection with a limiting r-band magnitude of 18–21. The dotted lines represent the corresponding distributions for the kilonova sources, as in Fig. 3. In the left (resp. right) panel, a value φ = 1 (resp. φ = 10, corresponding to particularly energetic jets or dense circum-merger media) was adopted in Eq. (7).