Dependence of $f_{\mathrm{esc}}^{\mathrm{LyC}}$ on the total spectral index measured across C- (6 GHz) and S- (3 GHz) bands. The left panel shows the dependence on $f_{\mathrm{esc}}^{\mathrm{LyC}}$ measured using the UV-fit method. And the right panel shows the dependence on $f_{\mathrm{esc}}^{\mathrm{LyC}}$ measured using the Hβ method Flury et al. (2022a). The blue points in both panels show LyC detections and the orange points show LyC non-detections (1σ upper limits). We also show two known nearby leakers from the literature, Haro 11 (brown star) and Tol 1247−232 (black star). In both panels the horizontal lines demarcate the regions for strong leakers ($f_{\mathrm{esc}}^{\mathrm{LyC}}>0.1$), weak leakers ($0.01<f_{\mathrm{esc}}^{\mathrm{LyC}}<0.1$), and non-leakers ($f_{\mathrm{esc}}^{\mathrm{LyC}}<0.01$). The vertical line shows the region above and below a spectral index of a standard radio-SED (${\alpha }_{6\mathrm{GHz}}^{3\mathrm{GHz}}=-0.64$) demarcating the region for flat and steep spectrum sources. See text for details.