2007ApJ...668L..23L

To explain the broadband spectral shape of knots in the M87 jet from radio through optical to X-rays, we propose a modified synchrotron model that considers the integrated effect of particle injection from different acceleration sources in the thin acceleration region. This results in two break frequencies at two sides of which the spectral index of knots in the M87 jet changes. We discuss the possible implications of these results for the physical properties in the M87 jet. The observed flux of the knots in the M87 jet from radio to X-rays can be satisfactorily explained by the model, and the predicted spectra from ultraviolet to X-rays could be further tested by future observations. The model implies that knots D, E, F, A, B, and C1 are unlikely to be candidates for the TeV emission recently detected in M87.