Fermi blazar的射电谱指数性质  

Properties of radio spectral index for Fermi blazars

作　　者：汪胜辉[1] 杨江河[1,2] 樊军辉[2] 张月莲 庹满先[1] 聂建军 陈秀慧 WANG ShengHui;YANG JiangHe;FAN JunHui;ZHANG YueLian;TUO ManXian;NIE JianJun;CHEN XiuHui(College of Mathematics and Physics Science,Hunan University of Arts and Science,Changde 415000,China;Center for Astrophysics,Guangzhou University,Guangzhou 510006,China)

机构地区：[1]湖南文理学院数理学院,常德415000 [2]广州大学天体物理中心,广州510006

出　　处：《中国科学：物理学、力学、天文学》2023年第8期193-204,共12页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:U2031112,U2031201,11733001);湖南省教育厅研究基金(编号:20C1273);广东省基础与应用基础研究重大项目(编号:2019B030302001);中国载人航天工程科学研究项目(编号:CMS-CSST-2021-A06)资助。

摘　　要：以Fermi/LAT 4FGL-DR3中blazar为样本,绘制了其射电能谱图(logf_(ν)-logν).根据散点的分布趋势,分别用一次、二次或三次曲线对能谱进行了拟合,最后得到2347个blazar的能谱及其拟合曲线的参数.根据拟合结果给出了0.05,0.1,0.5,1.4,5,8,15,50和150 GHz等9个频率处的射电谱指数.讨论了平均谱指数随频率的变化,以及同步辐射谱曲率与射电谱指数的关系.结果表明:平均射电谱指数在-0.1–1的范围内变化,在1–50 GHz频率范围内,谱指数变化幅度最小(0–0.2);在同一频率处,不同子类blazar的平均谱指数不同,且有■;随着射电辐射频率的增加,平均谱指数先减小后增加,呈开口向上的抛物线形状;按照散点的分布趋势,射电能谱图可分成3种类型(Λ,V和S型),3种类型源的射电谱均应是小尺度和大尺度喷流辐射成分的合成,但Λ与V型源中的2种成分可能不同;各子类blazar的同步辐射谱曲率与射电谱指数有较好的正相关关系,射电辐射对低同步峰频BL Lac(LBL)、平谱射电源(FSRQ)、高同步峰频BL Lac(HBL)的同步辐射谱的影响依次减弱.Taking the blazars in Fermi/LAT(large area telescope) 4FGL-DR3 as a sample,the radio energy spectrum(logf_ν-logν)was obtained.According to the distribution trend of scattered points,the energy spectrum was fitted with the primary,quadratic,or cubic curves,and the parameters of the 2347 blazars energy spectrum and its fitting curve were obtained.The radio spectrum indices at 9 frequencies,such as 0.05,0.1,0.5,1.4,5,8,15,50,and 150 GHz,are given according to the fitting results.The variation in the average spectral index with frequency and the correlation between the synchrotron spectral curvature and the radio spectral index are discussed.The results indicate that(1) the average radio spectral index changes in the range of -0.1–1,and the spectral index changes with the smallest amplitude(0–0.2) in the range of 1–50 GHz;(2) at the same frequency,the average spectral index differs among subclasses of blazars,and ■;(3) with increasing frequency,the average spectral index first decreases and then increases,showing an open upward parabola;(4) according to the distribution trend of scattered points,the radio spectrum can be divided into three types(Λ,V,and S),comprising inner and outer jet radiation,but the two components in the Λ-and V-type sources may differ;(5) the synchrotron spectral curvature positively correlates with the radio spectral index,and the effect of radio radiation on the synchrotron radiation spectra of Low synchrotron peak BL Lacs(LBL),flat spectrum radio quasars(FSRQs),and high synchrotron peak BL Lacs(HBL)decreases in turn.

关 键 词：耀变体 射电辐射 谱指数 

分 类 号：P157.6[天文地球—天文学]