活动星系核是当今天体物理最活跃的研究领域之一，是Fermi/LAT最重要的发现。而耀变体是活动星系核中最具观测特性的天体，但是它们的辐射机制，尤其是高能辐射机制是不够清楚的。它们可分为BL天体和平谱射电源，或者根据同步峰频的大小分为低峰频，中峰频和高峰频源。有人提出耀变体存在“耀变体序列”，但受到观测的挑战。不同作者根据各自的研究样本和同步峰频给出了耀变体的分类，但是分类频率区间各不相同。本项目将利用最大的耀变体样本（包括被（未被）Fermi探测到的天体）开展它们的分类和辐射机制研究。研究内容包括：（１）计算它们的能谱分布，对它们进行分类和相关性研究；（２）利用Fermi数据库对典型的耀变体开展数据处理，研究它们的光变特性与辐射机制；（３）研究“耀变体序列”是物理的还是某种效应；（４）研究Fermi源中未证认源的光变特性，给出BL天体和平谱射电源候选体；（５）研究喷流是连续的还是球形的。

Active galactic nuclei (AGNs) is one of active topics in modern astrophysics, they are also the important discovery of Fermi/LAT mission. Blazars are a special subclass of AGNs, but their emission mechanism, particularly their emission mechanism for the high energetic emissions is still not very clear. Blazars are divided into BL Lac objects and flat spectrum radio sources, or they are divided into low-synchrotron-peak-frequency, intermediate- synchrotron-peak-frequency, and high-synchrotron-peak-frequency sources. A "Blazar sequence" was proposed but challenged with observations. The classifications, based on the synchrotron peak frequencies, of blazars are not consensus. In this project, we will compile the largest blazar sample including Fermi detected (and non-Fermi detected) ones to study the classifications and their emission mechanism. The main research contents include: (1) calculating the spectral energy distributions of blazars, making classifications and doing some mutual correlation analyses; (2) analyzing the light curves of some typical blazars using the Fermi data archive to study their variability properties and their emission mechanism; (3) studying whether the "Blazar Sequence" is of some physics meanings or only an apparent phenomenon caused by some effects; (4) studying the gamma-ray variability properties for the unidentified Fermi sources and then select the candidates of BL Lac objects and flat spectrum radio sources; (5) answering the jet to be continuous or spherical.