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Radio spectral index of BL Lac objects

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Science China(Physics,Mechanics & Astronomy) 2013年第5期56卷 1035-1040页

作者： yuan yuhai FAN JunHui LONG XiaoLi Center for Astrophysics Guangzhou University

In this paper, the preliminary data from University of Michigan Radio Astronomy Observatory database （UMRAO） are used to discuss the radio spectral index properties of 8 BL Lacs. To do so, we calculated the radio spectral index, a （F oc va）, which was obtained by fitting the averaged flux densities in the bands （4.8 GHZ, 8 GHz, and 14.5 GHz） by binning the original for 7 d. We also calculated the time delay between the averaged lightcurves and the spectral variance. Our calculations and analysis give the following results. 1） The averaged logarithmic flux density at 8 GHz （logF） and the corresponding spectral index （or） have strong correlation for all the BL Lacs; 2） the lightcurves and the spectral variability have the similar profile for all the BL Lacs; 3） the lightcurves delay spectral variability for all sources but PKS 0735＋178, with the delay time ranging from 31 d to 125 d.

关键词： galaxies BL Lacs spectral variability parameter time delay

Lorentz factor estimation for radio sources

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Science China(Physics,Mechanics & Astronomy) 2012年第8期55卷 1510-1514页

作者： YANG JiangHe FAN JunHui yuan yuhai 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 Laboratory Center Guangzhou University Guangzhou 510006 China

In this paper, a sample including 68 blazars (18 BL Lacs and 50 FSRQs) with known Doppler factors and superluminal velocity from our previous papers is presented. Both the Lorentz factors (/') and viewing angles (0) are estimated for the 68 sources The relationship between BL Lacs and FSRQs is also revisited using the two variables off'and 0. The Lorenz factors are in the range of 2.33 to 64.07. The viewing angles are in the range of 0.04 to 24.56. The averaged value of the viewing angle for BL Lacs is slightly larger than that for FSRQs, while the averaged value of the Lorentz factor for BL Lacs is smaller than that for FSRQs.

关键词： radio sources Lorentz factor viewing angle

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

人工智能时代语言服务行业需求分析与人才培养研究

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湖南大学学报（社会科学版） 2024年第2期38卷 95-102页

作者：邓媛杨屿海袁庆湖南大学外国语学院湖南长沙410082 安克创新科技股份有限公司湖南长沙410205 国防科技大学军事外语系湖南长沙410073

以126名语言服务从业者及397名学习者为研究对象进行问卷调查和访谈,通过数据分析发现,人工智能时代的语言服务行业对具职业创新能力的复合型人才需求较高,但现有人才培养与市场需求还不能完全对接,学习者对行业需求的认识,以及自身信... 详细信息

以126名语言服务从业者及397名学习者为研究对象进行问卷调查和访谈,通过数据分析发现,人工智能时代的语言服务行业对具职业创新能力的复合型人才需求较高,但现有人才培养与市场需求还不能完全对接,学习者对行业需求的认识,以及自身信息技术能力、跨学科语言服务能力等有待提升。提出多渠道语言服务能力培养路径,特别探讨了通过依托项目学习模式,提升学习者职业创新能力,以期培养人工智能时代行业所需的优质语言服务人才。

关键词：人工智能语言服务人才培养

《聊斋志异》及其仿作的评书改编——兼论文言小说的评书改编难度

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明清小说研究 2024年第2期 169-182页

作者：李源高玉海浙江师范大学

《聊斋志异》的评书改编在每个历史阶段表现出不同特点。传统评书时代,《聊斋》评书不但演说地域广,而且形成了颇具影响力的评书流派——陈派。广播评书时代,天津市文化局对《聊斋》评书进行了抢救式整理,保存了珍贵的说书资料。网络评... 详细信息

《聊斋志异》的评书改编在每个历史阶段表现出不同特点。传统评书时代,《聊斋》评书不但演说地域广,而且形成了颇具影响力的评书流派——陈派。广播评书时代,天津市文化局对《聊斋》评书进行了抢救式整理,保存了珍贵的说书资料。网络评书时代,《聊斋》评书的改编篇数和题材类型增加,并向照本宣科式复归。《聊斋志异》的仿作虽多,仅《阅微草堂笔记》《子不语》《夜雨秋灯录》进行了较为系统的评书改编。改编数量少的原因是文言小说改编难度大。通过分析在评书改编过程中的书目选择、文本改编、故事演说、听众收听等四个环节,考察文言小说改编的难度。

关键词：《聊斋志异》仿作评书改编文言小说

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一种用于不均匀采样频谱分析的新方法

牡丹江师范学院学报（自然科学版） 2006年第4期32卷 26-27页

作者：袁聿海广州大学实验中心广东广州510006

引入Jurkevich方法来处理实际中所遇到的非均匀、非理想状况下采样的频谱分析,结合Kidger方法对结果进行了处理,并通过此方法在天文学中的实际应用阐述了该方法的有效性.

关键词：频谱分析方差采样样本

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