Synchrotron properties for different magnetic field strengths (left panels) and injection parameter x_inj (right panels). Top panel shows luminosity evolution; the blue, orange, and green lines show radio, optical, and X-ray band respectively. Bottom panel shows spectral index evolution. The solid lines represent the fiducial model with β = 10 (left) or x_inj = 3.6 (right), while the dashed and dotted lines represent β = 1 (left), x_inj = 3.2 (right) and β = 100 (left), x_inj = 3.9 (right) respectively.