Spectral Energy Distribution for Some Fermi Blazarstwo

The observational data from radio to X-ray wavebands were collected from the SSDC (Italian Space Agency Science Data Center) for 68 Fermi blazars, and their spectral energy distributions (SEDs) were calculated by means of the least square fitting with a log-parabolic function. Based on the SED fitting parameters, the correlations of the synchrotron peak frequency, curvature and effective spectral index were discussed, and an empirical formula was also proposed to estimate the synchrotron peak frequencies by using the effective spectral indexes. The main results are as follows: (1) From the linear correlation between the synchrotron peak frequency (lg νp) and the curvature (k), we find that the result supports the energy-dependent acceleration probability model for all BL Lac objects, while the result for the BL Lac objects of lg νp > 15.3 is consistent with the model of fluctuation of fractional acceleration gain. (2) For the sources of nearly same lg νp, a significant correlation between the effective spectral index αro of the radio-optical waveband and the curvature is detected, while the effective spectral index αox of the optical-x-ray waveband is not correlated with the curvature. According to the effective spectral index αro, a relation between the synchrotron peak frequency and the curvature can be defined.