SED of the BS of BD+43°3654 between 100 MHz and 15 GHz. The dashed green, dotted orange, and solid light blue lines are the synchrotron, free–free (IL) and total emission curves calculated with our model. The magenta arrows are the lower limits of Benaglia et al. (2010). The grey data points show the SED reported by Benaglia et al. (2021) when selecting contours > 1.5 mJy beam⁻¹, and the black data points show the SED from contours > 2.3 mJy beam⁻¹. The dark red data points show the SED reported by Moutzouri et al. (2022). The dark blue bar is the total flux obtained from the WENSS emission map at 325 MHz (Appendix A).