Jet radius profile as a function of distance z from the black hole. The distance is displayed in units of R_g (top axis) and milliarcsecond (bottom axis). Error bars represent ±1σ uncertainties. The solid line represents the best-fit broken power-law model. The dotted line represents an extrapolation of the inner part of the best-fit model. The vertical dashed line indicates the location of the break in the jet width profile, $z_{\mathrm{b}}^{\mathit{w}}$.