Effective spectral index properties for Fermi blazars

作     者：JiangHe Yang JunHui Fan Yi Liu YueLian Zhang ManXian Tuo JianJun Nie YuHai Yuan 

作者机构：Department of Physics and Electronics Science Hunan University of Arts and Science Changde 415000 China Center for Astrophysics Guangzhou University Guangzhou 510006 China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006 China Mathematics and Computational Science Hunan University of Arts and Science Changde 415000 China 

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：2018年第61卷第5期

页      面：46-52页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.U1431112,U1531245,11733001,and 11403006) the Innovation Foundation of Guangzhou University(IFGZ) the Guangdong Innovation Team(Grant No.2014KCXTD014) Astrophysics Key Subjects of Guangdong Province and Guangzhou City the Hunan Provincial Natural Science Foundation of China(Grant No.2015JJ2104) the Research Foundation of the Education Bureau of Hunan Province,China(Grant No.16C1081) 

主　　题：active galactic nuclei (AGNs) blazars effective spectral index 

摘      要：Blazars are a special subclass of active galactic nuclei with extreme observation properties. This subclass can be divided into two further subclasses of flat spectrum radio quasars(FSRQs) and BL Lacertae objects(BL Lacs) according to their emission line features. To compare the spectral properties of FSRQs and BL Lacs, the 1.4 GHz radio, optical R-band, 1 keV X-ray, and 1 GeVy-ray flux densities for 1108 Fermi blazars are calculated to discuss the properties of the six effective spectral indices of radio to optical(α_(RO)), radio to X-ray(α_(RX)), radio to y ray(α_(Ry)), optical to X-ray(α_(OX)), optical to y ray(α_(Oy)), and X-ray to y ray(α_(Xy)).The main results are as follows: For the averaged effective spectral indices, α_(OX_ α_(Oy) α_(Xy) α_(Ry) α_(RX) α_(RO) for samples of whole blazars and BL Lacs; α_(Xy)≈α_(Ry)≈α_(RX) for FSRQs and low-frequency-peaked BL Lacs(LBLs); and α_(OX)≈α_(Oy)≈α_(Xy) for high-synchrotron-frequency-peaked BL Lacs(HBLs). The distributions of the effective spectral indices involving optical emission(α_(RO), α_(OX), and α_(Oy)) for LBLs are different from those for FSRQs, but if the effective spectral index does not involve optical emission(α_(RX), α_(Ry), and α_(Xy)), the distributions for LBLs and FSRQs almost come from the same parent population. X-ray emissions from blazars include both synchrotron and inverse Compton (IC) components; the IC component for FSRQs and LBLs accounts for a larger proportion than that for HBLs; and the radiation mechanism for LBLs is similar to that for FSRQs, but the radiation mechanism for HBLs is different from that for both FSRQs and LBLs in X-ray bands. The tendency of α_(Ry) decreasing from LBLs to HBLs suggests that the synchrotron self-Compton model explains the main process for highly energetic y rays in BL Lacs.