Left: Jet radius R_j at z = 2 kpc (top), average energy per lepton $\overline{ϵ}{\prime }_{\mathrm{e}}$ (second), average proton fraction within the jet (third), and axial deceleration distance z(v = 0.9c) (bottom) as a function of the jet power L_j, for two stellar core radii r_c, s (see legend). Each symbol corresponds to one simulation. The circles indicate simulations where the jet remains relativistic throughout the full 2 kpc box; the triangles indicate simulations where the jet decelerates before 2 kpc, for which the jet radius is obtained by extrapolation (see Sect. 3). The dashed line in the bottom panel marks the 2 kpc box limit. Right: Same as left but shown as a function of the stellar distribution core radius r_c, s for fixed jet powers (see legend).