耀变体(blazars)是活动星系核中活动性很强的一类天体，该类天体从射电波段到γ射线波段均探测到了辐射且存在剧烈光变。辐射机制问题是耀变体研究的核心问题之一，但高能γ射线波段的辐射机制尚存争议。仅根据能谱信息，很难对辐射机制进行更多限制，从而难以甄别何种机制更为有效。除了能谱之外，不同波段光变相关性信息以及由光变获得的辐射区物理环境能够为建立和区分辐射模型提供重要信息和限制。本项目基于这一思想，拟对耀变体进行大样本研究，研究射电、光学、X射线及γ射线等四个波段之间光变的相关性特点，同时采用结构函数法寻找光变时标并据此估计辐射区的尺度大小等物理参量，并且利用功率谱密度法研究不同波段光变的异同，进而对现有辐射机制进行探讨。本项目的开展，不仅可以更深入了解耀变体不同子类不同波段的光变特点，还将为进一步建立或改进耀变体高能辐射模型提供重要信息和限制，从而有助于耀变体高能辐射机制问题的解决。

Blazars are the most extreme class of active galactic nuclei (AGNs) and exhibit strong and rapid variability across the entire electromagnetic (EM) spectrum. The radiation mechanism is an important issue. However, it is still in dispute at higher frequencies. Besides spectral energy distribution (SED), variability has been one of the most powerful tools in revealing the nature of blazars. Variability and the relation between different energy bands provide very important constraints for the interpretation of the emission components. Our goals are to investigate the correlations between different energy bands (radio, optical, X-ray and γ-ray), and search for time scales in the light curves using the structure function (SF) method and then estimate the emission size, the magnetic field strength and the doppler factor. Another goal is to study the power spectral densities (PSDs) of different energy bands, and discuss the radiation mechanism. This study will help us to understand the variability of blazars and provide more information and constraints for the radiation mechanism.