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An X-ray luminosity analysis for FRIs and FRIIs

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Science china(Physics,Mechanics & Astronomy) 2009年第9期52卷 1434-1441页

作者： zhang ChunLing fan junhui center for astrophysics Guangzhou UniversityGuangzhou 510006China

Radio galaxies are divided into two groups according to their luminosities at 178 MHz, namely Fa- naroff-Riley type Is (FRIs) and fanaroff-Riley type IIs (FRIIs) with FRIs showing lower radio luminosities than FRIIs. In this paper, the X-ray data are compiled for 183 radio galaxies (61 FRIs and 122 FRIIs), from the available literature, for the analysis of the X-ray properties. The 1 keV X-ray luminosities are calculated and discussed for the two groups, and an averaged X-ray luminosity of logLX1 keV = 41.30±2.51 erg·s-1·keV-1 is found for FRIs, which is lower than that for FRIIs, logLX1 KeV = 43.39±3.06 erg·s-1·keV-1. A Kolmogorov-Smirnov (K-S) test indicates that the probability for the X-ray luminosity distributions of the two groups to be from the same parent distribution is 1.44×10-10. We also discuss the origin and the mechanism of the X-ray emission for FRIs and FRIIs.

关键词： active galactic nuclei radio galaxies relativistic beaming

Investigating jet physical properties of Fermi blazars with broad-line emissions

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中国科学:物理学、力学、天文学英文版 2023年第10期66卷 138-154页

作者： Lixia zhang Jianghe Yang Yi Liu junhui fan center for astrophysics Guangzhou UniversityGuangzhou 51006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China Key Laboratory for Astronomical Observation and Technology of guangzhou Guangzhou 510006China Great Bay center National Astronomical Data CenterGuangzhou 510006China Department of Physics and Electronics Science Hunan University of Arts and ScienceChangde 415000China

Relativistic outflows often exhibit extreme observational characteristics due to beaming effects, which makes measuring their jet power a challenging task. Although the spectral energy distribution(SED) obtained from multi-wavelength data can constrain the physical parameters of these jets, accurately estimating the Doppler factor remains difficult. To address this challenge, we assemble a comprehensive sample containing available SEDs of synchrotron and inverse Compton(IC) components, monochromatic luminosity, and broad-line region(BLR) emissions. We employ a parabolic equation to fit the synchrotron radiation SEDs,constraining jet physical parameters within the framework of a one-zone leptonic model. Our study delves into the jet properties and Doppler factor estimations, yielding the following key findings:(1) The fitting results of SED data for the entire sample reveal normal distributions of jet physical parameters for two subclasses of blazars.(2) Correlation analysis demonstrates that synchrotron peak luminosity exhibits a proportional relationship with both the radio and the γ-ray luminosities.(3) We introduce a novel method for estimating Doppler factors, which uncovers discrepancies between Doppler factors from this work and others from different techniques.

关键词： active galactic nuclei blazars jets spectral energy distribution

Effective spectral index properties for Fermi blazars

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Science china(Physics,Mechanics & Astronomy) 2018年第5期61卷 46-52页

作者： JiangHe Yang junhui fan Yi Liu YueLian zhang ManXian Tuo JianJun Nie YuHai Yuan 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

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.

关键词： active galactic nuclei (AGNs) blazars effective spectral index

Comparison between Fermi detected and non-Fermi detected superluminal sources

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Science china(Physics,Mechanics & Astronomy) 2019年第12期62卷 110-125页

作者： HuBing Xiao junhui fan JiangHe Yang Yi Liu YuHai Yuan Jun Tao Denise Costantin YuTao zhang ZhiYuan Pei LiXia zhang WenXin Yang center for astrophysics Guangzhou UniversityGuangzhou 510006China Department of Physics and Astronomy University of PadovaPadova PD 35131Italy Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China Department of Physics and Electronics Science Hunan University of Arts and ScienceChangde 415000China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 210006China

Active galactic nuclei（AGNs） have been attracting research attention due to their special observable properties. Specifically,a majority of AGNs are detected by Fermi-LAT missions, but not by Fermi-LAT, which raises the question of weather any differences exist between the two. To answer this issue, we compile a sample of 291 superluminal AGNs（189 FDSs and 102 nonFDSs） from available multi-wavelength radio, optical, and X-ray（or even γ-ray） data and Doppler factors and proper motion（μ）(or apparent velocity(βapp)); calculated the apparent velocity from their proper motion, Lorentz factor（Γ）, viewing angle（?） and co-moving viewing angle(?co) for the sources with available Doppler factor（δ）; and performed some statistical analyses for both types. Our study indicated that（1） in terms of average values, FDSs have higher proper motions（μ）, apparent velocities(βapp),Doppler factor（δ）, Lorentz factor（Γ）, and smaller viewing angle（?）. Nevertheless, there is no clear difference in co-moving viewing angles（?∞）. The results reveal that FDSs show stronger beaming effect than non-FDSs.（2） In terms of correlations:1) both sources show positive, mutually correlated fluxes, which become closer in de-beamed fluxes; 2) with respect to apparent velocities and γ-ray luminosity, there is a tendency for the brighter sources to have higher velocities; 3) with regard to viewing angle and observed γ-ray luminosity, log? =-（0.23 ± 0.04）log Lγ+（11.14 ± 1.93）, while for the co-moving viewing angle and the intrinsic γ-ray luminosity, log?∞=（0.09 ± 0.01）log Lγn-（1.73 ± 0.48）. These correlations show that the luminous γ-ray sources have smaller viewing angles and a larger co-moving viewing angle, which indicate a stronger beaming effect in γ-ray emissions.

关键词： active galactic nuclei jets γ-rays correlations

Estimation of inverse Compton peak frequency for 4FGL Blazars

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Science china(Physics,Mechanics & Astronomy) 2023年第4期66卷 142-157页

作者： JiangHe Yang junhui fan Yi Liu ManXian Tuo ZhiYuan Pei WenXin Yang YuHai Yuan SiLe He ShengHui Wang XiaoHai Qu YueLian zhang JianJun Nie XiuHui Chen College of Mathematics and Physics Science Hunan University of Arts and ScienceChangde 415000China center for astrophysics Guangzhou UniversityGuangzhou 510006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China

This study uses a parabolic equation to fit the Inverse Compton (IC) spectral component of 3743 blazars (794 FSRQs,1432 BLLacs,and 1517 BCUs) from the 4FGL-DR3 *** mutual correlations are investigated,and a Bayesian classification is performed to the IC peak *** analyses draw the following conclusions:(1) The Bayesian classification shows two components with a dividing boundary of log(v_(p)^(IC)/Hz)pIC=***,the 3743 blazars are divided into low IC peak frequency(LCP) blazars and high IC peak frequency (HCP) blazars.(2) A strong linear correlation exists between IC peak frequency(logv_(p)^(IC)) and γ-ray photon spectral index (Γ).The IC peak frequency can be estimated by an empirical relation logv_(p)^(IC)=–4.5·Γ+32.8 for BL Lacs and logv_(p)^(IC)=4.0+31.4pICfor FSRQs,which is consistent with the result by Abdo et al.(3) The ICspectral curvature and IC peak frequency are not as closely related as the synchrotron curvature and the synchrotron peak frequency.(4) An anti-correlation exists between IC peak frequency and IC peak luminosity,implying that as the IC peak frequency in the γ-ray band decreases,the source becomes more *** beaming effect is stronger for the source with a lower IC peak frequency.(5) Positive correlations exist between IC and synchrotron components for both peak frequencies and peak fluxes,but no clear correlation exists between IC curvature and synchrotron curvature.

关键词： active galactic nuclei Fermi blazars spectral energy distribution inverse Compton emission

费米耀变体的伽马辐射与发射线辐射的相关分析（英文）

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天文研究与技术 2019年第4期16卷 390-400页

作者：张丽霞樊军辉袁聿海广州大学天体物理中心广东广州510006 广东省高等学校天文观测与技术重点实验室广东广州510006

在活动星系核的标准模型中,中心有一个超大质量黑洞,黑洞周围是一个吸积盘,喷流处在垂直于吸积盘的平面上。理论研究表明,喷流和吸积盘之间存在一定的联系,许多学者利用射电(或伽马)辐射与发射线辐射之间的相关性研究这种关系。然而,耀... 详细信息

在活动星系核的标准模型中,中心有一个超大质量黑洞,黑洞周围是一个吸积盘,喷流处在垂直于吸积盘的平面上。理论研究表明,喷流和吸积盘之间存在一定的联系,许多学者利用射电(或伽马)辐射与发射线辐射之间的相关性研究这种关系。然而,耀变体的射电或伽马辐射具有强烈的成束效应,使得在讨论喷流-吸积盘的联系时,应该考虑成束效应。收集了202个FERMI/LAT耀变体的宽发射线数据研究喷流与吸积的关系。202个源中,66个具有多普勒因子。对整个样本和平谱射电类星体与蝎虎座BL型天体2个子样本,分别研究了去除红移影响和成束放大效应时,伽马射线与宽发射线以及射电波段与宽发射线的相关关系,得到整个样本202个源的伽马射线与宽发射线以及射电波段与宽发射线之间存在强的正相关,而且这种相关性在去除红移效应之后仍然存在。对于66个有多普勒因子的源,在去除多普勒因子的影响之后,伽马射线与宽发射线以及射电波段与宽发射线之间仍然存在正相关。分析结果表明:(1)整个样本和各个子类的伽马射线与宽发射线之间都存在强相关。这些相关性在红移效应去除后仍然存在,并且证实了文献中他们所研究的结果。(2)对于66个有多普勒因子的耀变体,宽发射线与多普勒因子之间存在强的相关性,伽马射线与宽发射线在去除多普勒因子的影响之后存在相关性。在射电和宽发射线之间也得到了类似的结果。(3)吸积过程与喷流之间存在强关联性。

关键词：宽发射线活动星系核蝎虎座BL型天体伽马射线辐射

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Fermi blazar的射电谱指数性质

中国科学：物理学、力学、天文学 2023年第8期53卷 193-204页

作者：汪胜辉杨江河樊军辉张月莲庹满先聂建军陈秀慧湖南文理学院数理学院常德415000 广州大学天体物理中心广州510006

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,... 详细信息

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.

关键词：耀变体射电辐射谱指数

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耀变体的峰频估计（英文）

湖南文理学院学报（自然科学版） 2017年第1期29卷 13-18,34页

作者：张丽霞林潮樊军辉杨江河广州大学物理与电子工程学院广东广州510006 广州大学天体物理中心广东广州510006 广东省教育厅天文科学与技术实验室广东广州510006 湖南文理学院物理与电子科学学院湖南常德415000

收集了60个耀变体样本,考察了有效谱指数(α_(RO),α_(OX)和α_(RX))与同步峰频(logv_p^s)之间的关系。斯皮尔曼秩检验的结果显示有效谱指数与同步峰频之间有很好的反相关。根据两者的相关给出了同步峰频与有效谱指数关联的经验公式。... 详细信息

收集了60个耀变体样本,考察了有效谱指数(α_(RO),α_(OX)和α_(RX))与同步峰频(logv_p^s)之间的关系。斯皮尔曼秩检验的结果显示有效谱指数与同步峰频之间有很好的反相关。根据两者的相关给出了同步峰频与有效谱指数关联的经验公式。通过该公式用α_(RO)和α_(OX)估算了耀变体的同步峰频,所得结果与文献的经验公式结果进行了比较,发现本文公式的结果更精确。

关键词：活动星系核耀变体同步峰频