Turnover frequency, linear size relationship for both our sources and those described in Table A.1 with different FFA model parameters. The light blue solid line, the magenta dashed line, and the dark blue dotted line represent FFA models where E  =  10⁴³, 10^42.5, and 10⁴² ergs s⁻¹, respectively, δ  =  2, and n₀ reaches 0.1 cm⁻³ at 1 kpc, which well describe our sources. The green line represents the required FFA model from Bicknell et al. (1997) to replicate the power-law slope from Eq. (5), where δ  =  −0.75, n₀  =  100 cm⁻³ and E  =  10^45.5 ergs s⁻¹. Red circles represent our sources, black squares represent sources listed in Table A.1, arrows indicate maximum linear sizes for unresolved sources, and black circles indicate sources with unknown redshifts (set to 1 for this plot).