Similar radiation mechanism in gamma-ray bursts and blazars: evidence from two luminosity correlations

Active galactic nuclei (AGNs) and gamma-ray bursts (GRBs) are powerful astrophysical events with relativistic jets. In this Letter the broadband spectral properties are compared between GRBs and the well-observed blazars. The distribution of GRBs are consistent with the well-known blazar sequence including the $\nu L_\nu(5\rm GHz)-\alpha_{\rm RX}$ and $\nu L_\nu(5\rm GHz)-\nu_{\rm peak}$ correlations, where $\alpha_{\rm RX}$ is defined as the broadband spectral slope in radio-to-X-ray bands, and $\nu_{\rm peak}$ is defined as the spectral peak frequency. Moreover, GRBs occupy the low radio luminosity end of these sequences. These two correlations suggest that GRBs could have a similar radiation process with blazars both in the prompt emission and afterglow phases, i.e., synchrotron radiation.