Parameter constraints in the 2D space (﹩{\beta }_{0},A﹩) with observations. The red oblique-line region shows the X-ray flux constraint. The blue grid (pink shaded) region shows the constraint from the upper limit of 9 GHz, without (with) free–free absorption taken into account. The parameters used are ﹩{\epsilon }_{B}=0.1﹩, ﹩{\epsilon }_{{\rm{e}}}=0.1﹩, p = 3, and ﹩{T}_{{\rm{e}}}=2.0\times {10}^{4}\,{\rm{K}}﹩.