Our models for s_CRe obtained with Eq. (3) and their impact on the modeled synchrotron spectral index β_syn. Colors correspond to the same models in all panels. Left panel: j_e from models A, B, C, and D with parameters listed in Table 1 that fit the black data points from Voyager (E < 10⁸ eV, Cummings et al. 2016; Stone et al. 2019) and Fermi-LAT (E > 10¹⁰ eV, Ackermann et al. 2010). Central panel: s_CRe values corresponding to the same models as in the left panel. Right panel: values of β_syn for the same models as in the other panels with the observed spectral indices from G 11 in hatches – the 16th, 50th, and 84th percentiles are marked as in Fig. 1. Models for s_CRe and β_syn using j_e from Orlando (2018) and Padovani et al. (2018) are also shown in dashed purple and teal lines in the central and right panels, respectively.