Fermi Blazar辐射性质研究

Blazar是活动星系核中活动最剧烈的一类天体，从射电到γ - ray整个电磁波段都有强的电磁波辐射。然而，它们的辐射机制特别是高能γ - ray辐射机制目前还不十分清楚。本项目将以最新Fermi/LAT观测到的blazar (Fermi blazar)为研究对象，利用国内设备进行光学观测，并结合Fermi/LAT的观测数据和其他波段历史数据，从以下3方面研究Fermi blazar的多波段性质和辐射机制： (1) 以4FGL blazar为样本，计算其多波段能谱分布，给出同步辐射峰频和逆康普顿峰频及其他相关物理参量；(2) 利用blazar的γ - ray不同能段的数据，研究γ - ray几个能段与低能波段(射电、光学和X - ray) 辐射之间的相关；(3) 寻找具有类型特征的blazar参量或关系，对blazar进行分类，研究不同类blazar的辐射机制。本项目还将对观测源中有明显光变的源进行光变研究。

Blazar is the most active subclass in the active galactic nuclei. It shows strong electromagnetic emissions through the whole electromagnetic wavebands from radio to γ - rays. However, it is not quite clear for the multi-band emissions mechanism, especially at the high energetic γ-ray region. In this proposal, we will take the latest Fermi blazar catalogue observed by Fermi/LAT as the research targets, make optical observations using the domestic telescopes, combine the observation data of Fermi/LAT, and the historical data at other wavebands to study their multi-wavelength properties and the emission mechanisms from following three aspects: (1) Based on the 4FGL blazar sample, we will calculate their spectrum energy distributions (SEDs), obtain the synchrotron peak frequency and the inverse Compton peak frequency, and some other corresponding parameters; (2) Using the multi-energy-band data in the γ - ray region given by Fermi/LAT, investigate the correlations between each γ - ray band and the lower energy (radio, optical and X - ray) emissions; (3) Looking for typical parameters or relations to classify blazars, and study the emission mechanisms corresponding to different types of blazars. We will also study the variability of the observedsources with obvious light variation.