Multi-wavelength variation properties of γ-ray-loud blazars

Abstract

Based on multi-waveband (radio, optical, and X-ray) observation data of 61 γ-ray-loud blazars (Cheng et al. 2000, ApJ, 537, 80) and γ-ray data by Hartman et al. (1999, AAA 72.002.011) we have studied the variability properties using the variability index, v = (Fmax - Fmin)/(Fmax + Fmin), and the relations between the flux density and both the redshift and the variability index. The mainly results are as follows: 1) the average variability indexes are almost the same within the error-bar range for the radio, optical, X-ray, and γ-ray bands. 2) The variabilities in the optical, X-ray, and γ-ray bands are found to be correlated with the flux densities of the source, implying that the more variable is the source, the brighter it is.