Radio core dominance of Fermi/LAT-detected AGNs

作     者：ZhiYuan Pei JunHui Fan Denis Bastieri JiangHe Yang HuBing Xiao ZhiYuan Pei;JunHui Fan;Denis Bastieri;JiangHe Yang;HuBing Xiao

作者机构：Diparimento di Fisica e Astronomia“G.Galilei”.Universita di PadovaPadova 1-35131Italy Istituto Nazionale di Fisica NucleareSezione di PadovaPadova 1-35131Italy Center for AstrophysicsGuangzhou UniversityGuangzhou 510006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong ProvinceGuangzhou 510006China Department of Physics and Electronics ScienceHunan University of Arts and ScienceChangde 415000China 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2020年第63卷第5期

页      面：105-123页

核心收录：

学科分类：080904[工学-电磁场与微波技术] 0810[工学-信息与通信工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080402[工学-测试计量技术及仪器] 0804[工学-仪器科学与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 081001[工学-通信与信息系统] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.11733001,and U1531245) the Natural Science Foundation of Guangdong Province(Grant No.2017A030313011) 

主　　题：active galactic nuclei(AGNs) quasars γ-rays 

摘      要：We present a sample of 4388 AGNs with available radio core-dominance parameters—defined as the ratio of the core flux densities to the extended ones, R = S_(core)/S_(ext).—which includes 630 Fermi-detected AGNs from the fourth source catalog(4FGL) of the Fermi Large Area Telescope(Fermi/LAT);the rest are non-Fermi-detected AGNs. In our sample, 584 blazars are Fermi-detected and 1310 are not. The sample also contains other subclasses, such as Seyferts, Fanaroff-Riley I/II galaxies, and normal *** investigate various properties of the Fermi-detected and non-Fermi-detected AGNs by using core-dominance parameters,capitalizing on a previous study which showed that R is a good indicator of beaming. We then calculate radio spectral indices for the whole sample, and adopt γ-ray-photon indices for the Fermi AGNs from the 4FGL catalog to discuss the properties of different subclasses. We obtain a relation between the core-dominance parameters and the radio spectral indices for both Fermi and non-Fermi sources, assuming a two-component model in the radio band. Our previous study ruled out the assumption that the core-dominance parameters and radio spectral indices are quite different for different AGN subclasses. This holds not only for Fermi sources but also for non-Fermi sources. In particular, R is, on average, greater for the former AGNs than for the *** this study, we enlarge our sample with available values of R to 4388 AGNs, and the obtained conclusions are consistent with our previous study. We assume that the same two-component model holds for the γ-ray band as for the radio band, and therefore,adopt the same relation between the core-dominance parameters and the γ-ray-photon indices for Fermi AGNs. Our fitting results indicate that the γ-ray emissions of Fermi blazars originate mainly from the jet, and therefore, we conclude that the Fermi blazars are beamed.