检索结果-南通市图书馆

同方期刊数据库

Highly variable γ-ray emission of CTD 135 and implications for its compact symmetric structure

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2021年第8期21卷 173-180页

作者： Ying-Ying Gan Hai-Ming Zhang Jin Zhang Xing Yang Ting-feng Yi yun-feng liang En-Wei liang Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China School of Physics Beijing Institute of TechnologyBeijing 100081China Department of Physics Yunnan Normal UniversityKunming 650500China

Theγ-ray emission properties of CTD 135,a typical compact symmetric object(CSO),are investigated with-11-year Fermi/LAT *** show that it has bright and significantly variable GeV emission,with theγ-ray luminosity of L_(γ)-10^(47) erg s^(-1) and a variation index of TS_(var)=1002.A quasi-periodic oscillation(QPO)with a periodicity of-460 days is detected in the global 95%false-alarm ***γ-ray emission features are similar to that of *** broadband spectral energy distribution(SED)can be attributed to the radiations of the relativistic electrons accelerated in the core region and the extended *** SED modeling shows that theγ-rays are from the core region,which has a Doppler boosting factor ofδ-10.8 and relativistically moves with a small viewing angle,being similar to blazar *** the base of the analysis results,we propose that the episodic activity of the central engine in CTD135 results in a blazar-like jet and the bubble-like lobes as the Fermi bubbles in the *** strong 7-ray emission with obvious variability is from the jet radiations and the symmetric radio structure is attributed to the *** jet radiation power and disk luminosity in units of Eddington luminosity of CTD 135 follow the same relation as other young radio sources,indicating that its jet radiation may also be driven by the Eddington ratio.

关键词： galaxies:active galaxies:jets radio continuum:galaxies gamma rays:galaxies

Is TOL 1326–379 a Prototype ofγ-Ray Emitting FR0 Radio Galaxy?

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第3期22卷 47-56页

作者： Wen-Jing Fu Hai-Ming Zhang Jin Zhang yun-feng liang Su Yao En-Wei liang Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China School of Physics Beijing Institute of TechnologyBeijing 100081China Max-Planck-Institute für Radioastronomie Auf dem Hügel 69D-53121 BonnGermany

With the possible spacial association to the Fermi/LAT source 3 FGL J 1330.0-3818,TOL 1326-379 may be the first one that is identified as a 7-ray emitting Fanaroff-Riley type 0 radio galaxy(FRO RG).We analyze the~12 yr Fermi/LAT observation data of thisγ-ray source and examine its association to TOL *** show that theγ-ray source(named as J1331.0-3818)is tentatively detected with a TS value of 28.7,3 FGL J 1330.0-3818 is out of the 95%containment of J1331.0-3818,and their positions are spatially separated~0°.2.4 FGL J1331.3-3818 falls into the 68%containment of J1331.0-3818,suggesting that our result agrees with that reported in the Fourth Fermi LAT Source *** 1326-379 is out of the 95%containment of J1331.0-3818,and their positions are spatially separated~0°.4,indicating that the association between J1331.0-3818 and TOL 1326-379 is quite ***,we do not find other possible potential radio or X-ray counterpart within the circle centered at J1331.0-3818 with a radius of 0°.*** spectral energy distribution(SED)of TOL 1326-379 shows a bimodal feature as seen in theγ-ray emitting *** fit the SED with the one-zone leptonic model and find that the average energy spectrum of J1331.0-3818 agrees with the model *** that J1331.0-3818 is an unidentified 7-ray source,we derive the upper-limit of theγ-ray flux for TOL *** is not tight enough to exclude this possibility with the SED *** on these results,we cautiously argue that theγ-ray source J1331.0-3818 is associated with TOL 1326-379 and its jet radiation physic is similar to thoseγ-ray emitting RGs.

关键词： radiation mechanisms:non-thermal galaxies:active galaxies galaxies:radio jets gamma-rays:galaxies

Revisit of GeV Gamma-Ray Emission from Orion B with the Fermi Large Area Telescope

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第9期24卷 128-135页

作者： Wei Zeng Xiao-Na Sun Rui-Zhi Yang Jia-Chun He Zhao-Dong Shi Ting-Ting Ge yun-feng liang En-Wei liang Guangxi Key Laboratory for Relativistic Astrophysics School of Physics Science and TechnologyGuangxi UniversityNanning 530004China Department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Key Labrotory for Research in Galaxies and Cosmology University of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China

We revisit the γ-ray emission above 300 Me V towards the massive star-forming region of Orion B by adopting14 yr observations with the Fermi Large Area Telescope and utilizing the updated software *** extended γ-ray emission region around Orion B is resolved into two components(region Ⅰ and region Ⅱ).The γ-ray spectrum of region I agrees with the predicted γ-ray spectrum assuming the cosmic ray(CR)density is the same as that of Alpha Magnetic Spectrometer(AMS-02)measured ***γ-ray emissivity of region II appears to be deficit at low energy band(E<3 GeV).Through modeling we find that CR densities exhibit a significant deficit below 20 Ge V,which may be caused by a slow diffusion inside the dense *** is probably caused by an increased magnetic field whose strength increases with the gas density.

关键词： (ISM:)cosmic rays gamma-rays:ISM (Galaxy:)open clusters and associations:individual(NGC 2023 NGC 2024 NGC 2068 and NGC 2071)

Search for gamma-ray spectral lines with the DArk Matter Particle Explorer

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2022年第7期67卷 679-684页

作者： DAMPE Collaboration yun-feng liang Laboratory for Relativistic Astrophysics Department of PhysicsGuangxi UniversityNanning 530004China

The DArk Matter Particle Explorer(DAMPE)is well suitable for searching for monochromatic and sharpγ-ray structures in the GeV-TeV range thanks to its unprecedented high energy *** this work,we search forγ-ray line structures using five years of DAMPE *** improve the sensitivity,we develop two types of dedicated data sets(including the BgoOnly data which is the first time to be used in the data analysis for the calorimeter-based gamma-ray observatories)and adopt the signal-to-noise ratio optimized regions of interest(ROIs)for different DM density *** line signals or candidates are found between 10 and 300 GeV in the *** constraints on the velocity-averaged cross section for xx→γγand the decay lifetime for x→γv,both at 95%confidence level,have been calculated and the systematic uncertainties have been taken into *** to the previous Fermi-LAT results,though DAMPE has an acceptance smaller by a factor of~10,similar constraints on the DM parameters are achieved and below 100 GeV the lower limits on the decay lifetime are even stronger by a factor of a *** results demonstrate the potential of high-energy-resolution observations on dark matter detection.

关键词： DAMPE Dark matter Gamma-ray Line-like structure

Dark Matter Search in Dwarf Irregular Galaxies with Ten Years of Data from the Ice Cube Neutrino Observatory

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第3期24卷 75-82页

作者： Yi-Fei Lü Ben-Yang Zhu Rong-Lan Li Xue-Kang Guo Tian-Ci Liu Yong-Bo Huang yun-feng liang Guangxi Key Laboratory for Relativistic AstrophysicsSchool of Physical Science and TechnologyGuangxi University Nanning 530004China

Dwarf irregular galaxies(dIrrs),as rotationally supported systems,have more reliable J-factor measurements than dwarf spheroidal galaxies and have received attention as targets for dark matter detection in recent *** this paper,we use 10 yr of IceCube muon-track data and an unbinned maximum-likelihood-ratio method to search for neutrino signals beyond the background from the directions of seven dIrrs,aiming to detect neutrinos produced by heavy annihilation dark *** do not detect any significant *** on such null results,we calculate the upper limits on the velocity-averaged annihilation cross section for 1 TeV–10 PeV dark *** limits,although weaker than the strictest constraints in the literature in this mass range,are also a good complement to the existing results considering the more reliable J-factor measurements of dIrrs.

关键词： (cosmology) dark matter-cosmology theory-galaxies dwarf

An algorithm to resolve γ-rays from charged cosmic rays with DAMPE

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2018年第3期18卷 25-36页

作者： Zun-Lei Xu Kai-Kai Duan Zhao-Qiang Shen Shi-Jun Lei Tie-Kuang Dong Fabio Gargano Simone Garrappa Dong-Ya Guo Wei Jiang Xiang Li yun-feng liang Mario Nicola Mazziotta Maria Fernanda Munoz Salinas Meng Su Valerio Vagelli Qiang Yuan Chuan Yue Jing-Jing Zang Ya-Peng Zhang yun-Long Zhang Stephan Zimmer Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China University of Chinese Academy of Sciences Beijing 100049 China Istituto Nazionale di Fisica Nucleare Sezione di Bari I-70125 Bari Italy Istituto Nazionale di Fisica Nucleare Sezione di Perugia I-06123 Perugia Italy Dipartimento di Fisica e Geologia Universita degli Studi di Perugia I-06123 Perugia Italy Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Department of Nuclear and Particle Physics University of Geneva CH- 1211 Switzerland School of Astronomy and Space Science University of Science and Technology of China Hefei 230026 China Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China Hefei 230026 China

The DArk Matter Particle Explorer（DAMPE）,also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne *** of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at～10 Ge V amounts to less than 1% of the selected ***,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar.

关键词： gamma rays general - instrumentation detectors - methods data analysis

DmpIRFs and DmpST:DAMPE instrument response functions and science tools for gamma-ray data analysis

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2019年第9期19卷 109-118页

作者： Kai-Kai Duan Wei Jiang yun-feng liang Zhao-Qiang Shen Zun-Lei Xu Yi-Zhong Fan Fabio Gargano Simone Garrappa Dong-Ya Guo Shi-Jun Lei Xiang Li Mario Nicola Mazziotta Maria Ferna Munoz Salinas Meng Su Valerio Vagelli Qiang Yuan Chuan Yue Stephan Zimmer Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing210033China University of Chinese Academy of Sciences Beijing100049China School of Astronomy and Space Science University of Science and Technology of ChinaHefei230026China Istituto Nazionale di Fisica Nucleare Sezione di Bari I-70125BariItaly Istituto Nazionale di Fisica Nucleare Sezione di Perugia I-06123PerugiaItaly Dipartimento di Fisica e Geologia Universita degli Studi di PerugiaI-06123PerugiaItaly Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China Department of Nuclear and Particle Physics University of GenevaCH-1211Switzerland Department of Physics and Laboratory for Space Research University of Hong KongPok Fu LamHong KongChina

Observing GeV gamma-rays is an important goal of the DArk Matter Particle Explorer(DAMPE)for indirect dark matter searching and high energy astrophysics. In this work, we present a set of accurate instrument response functions for DAMPE(DmpIRFs) including the effective area, point-spread function and energy dispersion, which are crucial for gamma-ray data analysis based on statistics from simulation data. A dedicated software named DmpST is developed to facilitate the scientific analyses of DAMPE gamma-ray data. Considering the limited number of photons and angular resolution of DAMPE, the maximum likelihood method is adopted in DmpST to better disentangle different source components. The basic mathematics and framework regarding this software are also introduced in this paper.

关键词： gamma rays:general instrumentation:detectors methods:statistical

在线全文

学校读者我要写书评

暂无评论

水下焊接机器人智能潜水送丝系统的研制

华南理工大学学报（自然科学版） 2014年第11期42卷 1-6页

作者：王振民冯锐杰冯允樑黄石生华南理工大学机械与汽车工程学院广东广州510640

文中针对水下机器人焊接的特点,研制了一种可用于水下熔化极气体保护焊的全数字智能潜水送丝系统.以数字信号控制器(DSC)级ARM CortexTM-M4架构的STM32F405RGT6微处理器为控制核心开发了全数字控制系统;设计了基于电机电枢电压负反馈的... 详细信息

文中针对水下机器人焊接的特点,研制了一种可用于水下熔化极气体保护焊的全数字智能潜水送丝系统.以数字信号控制器(DSC)级ARM CortexTM-M4架构的STM32F405RGT6微处理器为控制核心开发了全数字控制系统;设计了基于电机电枢电压负反馈的脉宽调制型半桥可逆斩波的送丝驱动电路,以补偿负载转矩变化带来的送丝速度的变化;开发了基于电涡流式接近开关的焊丝状态检测模块,实现了焊丝状态的非接触、实时监测.实验结果表明,所研制的系统能可靠地监测焊丝状态,在送丝软管状态变化的情况下能够均匀、稳定地送丝,送丝速度变化率小于±3.5%,远低于国家标准规定的数值.

关键词：水下焊接潜水送丝系统焊丝状态检测数字控制

Effect of the relative phase between pre-existing 2/1 and 3/1 magnetic islands on the suppression of runaway electrons on J-TEXT

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第7期32卷 71-77页

作者：熊金玉江中和焦子啸李振梁云峰陈忠勇丁永华 J-TEXT Team International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China Yangtze Memory Technologies Co. Ltd.Wuhan 430074China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031China Forschungszentrum J¨ulich GmbH Institut f¨ur Energie-und Klimaforschung-PlasmaphysikJ¨ulich 52425Germany

In the experiments of actively triggering plasma disruption by massive gas injection, the externally applied resonant magnetic perturbation has been used to mitigate the hazard of runaway electron(RE). Motivated by the experiment of multimode coupling to suppress REs on J-TEXT, some typical simulation cases with non-ideal MHD with rotation-open discussion(NIMROD) code are carried out to explore the influential mechanism of different relative phases between m/n =2/1 and m/n = 3/1 magnetic islands on the confinement of REs. Results show that the RE confinement is drastically affected by the relative phase between 2/1 and 3/1 magnetic islands. When the O point phase of 2/1 and 3/1 magnetic islands is toroidal 330°, REs can be effectively lost. The fitting curve of the remaining ratio of REs vs. the relative toroidal phase is predicted to approximate a sine-like function dependence. Further studies indicate that the phase difference between coexisting 2/1 and 3/1 islands can affect the radial transport of impurities. The loss of runaway electrons is closely related to the deposition effect of impurity. The impurity is easier to spread into the core region with smaller poloidal phase difference between the radial velocity of impurity and the impurity quantity of Ar.

关键词： major disruption runaway electron massive gas injection(MGI) resonant magnetic perturbation(RMP)