检索结果-南通市图书馆

Scintillation Arc from FRB 20220912A

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2024年第1期67卷 134-142页

作者： Zi-wei Wu Robert AMain wei-wei Zhu Bing Zhang Peng jiang jia-Rui Niu Jin-Lin Han Di Li Ke-jia Lee Dong-Zi Li Yuan-Pei Yang Fa-Yin Wang Rui Luo Pei Wang Chen-Hui Niu Heng Xu Bo-Jun Wang wei-Yang Wang Yong-Kun Zhang Yi Feng De-jiang Zhou Yong-Hua Xu Can-Min Deng Yu-Hao Zhu national astronomical observatories Chinese Academy of SciencesBeijing 100101China Max-Planck-Institut für Radioastronomie Bonn 53121Germany Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Nevada Center for Astrophysics and Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy University of Chinese Academy of SciencesBeijing 100049China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa Department of Astronomy Peking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Cahill Center for Astronomy and Astrophysics California Institute of TechnologyPasadena 91125USA South-Western Institute For Astronomy Research Yunnan UniversityKunming 650504China School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210023China CSIRO Space and Astronomy Epping 1710Australia Department of Astronomy School of Physics and Materials ScienceGuangzhou UniversityGuangzhou 510006China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China yunnan observatories Chinese Academy of SciencesKunming 650011China Guangxi Key Laboratory for Relativistic Astrophysics Department of PhysicsGuangxi UniversityNanning 530004China

We present the interstellar scintillation analysis of fast radio burst(FRB)20220912A during its extremely active episode in 2022using data from the Five-hundred-meter Aperture Spherical Radio Telescope(FAST).We detect a scintillation arc in the FRB’s secondary spectrum,which describes the power in terms of the scattered FRB signals’time delay and Doppler *** arc indicates that the scintillation is caused by a highly localized *** analysis favors a Milky Way origin of the ionized interstellar medium(IISM)for the localized scattering medium but cannot rule out a host galaxy *** present our method for detecting the scintillation arc,which can be applied generally to sources with irregularly spaced bursts or *** methods could help shed light on the complex interstellar environment surrounding the FRBs and in our Galaxy.

关键词： fast radio burst scintillation FRB 20220912A

Different Features of Jets and Isotropic Fireballs in Gamma-ray Burst Phase

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Astronomy and Astrophysics 2006年第1期6卷 69-76页

作者： Yun-Ming Dong lan-wei jia Xiao-Hong Zhao yunnan astronomical observatory/national astronomical observatories Chinese Academy ofSciences Kunming 650011 Graduate University of chinese academy of sciences Beijing 100049

We investigated physical quantities including the spectrum, emission lines and pulse profiles expected from a uniform jet, a spherical fireball and the 1/Г region （the portion of the spherical fireball with opening angle 1/Г） in the prompt emission phase, after taking into consideration of the Doppler effect under the fireball framework. Our study shows that： a） for these physical quantities the spherical fireball and the uniform jets do not present obvious differences, so we cannot use these to distinguish a spherical fireball from a uniform jet; b） for the spherical fireball and a uniform jet, the observed quantities mainly come from the 1/Г region, so we can simply use the 1/Г region in approximate calculations; c） broadening of emission lines is a general phenomena, which mainly comes from the curvature effect; d） the 1/Г region plays different roles in different frequency ranges, and the radiation from the 1/Г region is greater in the higher than in the lower frequencies.

关键词： gamma-rays: bursts--gamma-rays: theory--radiation mechanisms: non-thermal --relativity

Observation of spectral lines in the exceptional GRB 221009A

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2024年第8期67卷 187-206页

作者： Yan-Qiu Zhang Shao-Lin Xiong Ji-Rong Mao Shuang-Nan Zhang Wang-Chen Xue Chao Zheng jia-Cong Liu Zhen Zhang Xi-Lu Wang Ming-Yu Ge Shu-Xu Yi Li-Ming Song Zheng-Hua An Ce Cai Xin-Qiao Li Wen-Xi Peng Wen-Jun Tan Chen-wei Wang Xiang-Yang Wen Yue Wang Shuo Xiao Fan Zhang Peng Zhang Shi-Jie Zheng Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese academy of sciences Beijing 100049China yunnan observatories Chinese Academy of SciencesKunming 650011China Center for astronomical Mega-Science Chinese Academy of SciencesBeijing 100012China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China College of Physics and Hebei Key Laboratory of Photophysics Research and Application Hebei Normal UniversityShijiazhuang 050024China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China College of Electronic and Information Engineering Tongji UniversityShanghai 201804China

As the brightest gamma-ray burst ever observed,GRB 221009A provided a precious opportunity to explore spectral line *** this article,we performed a comprehensive spectroscopy analysis of GRB 221009A jointly with GECAM-C and Fermi/GBM data to search for emission and absorption *** the first time we investigated the line feature throughout this GRB including the most bright part where many instruments suffered problems,and identified prominent emission lines in multiple time *** central energy of the Gaussian emission line evolves from about 37 to 6 MeV,with a nearly constant ratio(about 10%)between the line width and central ***,we find that both the central energy and the energy flux of the emission line evolve with time as a power law decay with power law index of–1 and–2,*** suggest that the observed emission lines most likely origin from the blue-shifted electron positron pair annihilation 511 ke V *** find that a standard high latitude emission scenario cannot fully interpret the observation,thus we propose that the emission line comes from some dense clumps with electron positron pairs traveling together with the *** this scenario,we can use the emission line to directly,for the first time,measure the bulk Lorentz factor of the jet(Γ)and reveal its time evolution(i.e.,Γ~t^(-1))during the prompt ***,we find that the flux of the annihilation line in the co-moving frame keeps *** discoveries of the spectral line features shed new and important lights on the physics of GRB and relativistic jet.

关键词： GRB GRB 221009A emission line

The In-Flight Realtime Trigger and Localization Software of GECAM

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10期24卷 11-24页

作者： Xiao-Yun Zhao Shao-Lin Xiong Xiang-Yang Wen Xin-Qiao Li Ce Cai Shuo Xiao Qi Luo Wen-Xi Peng Dong-Ya Guo Zheng-Hua An Ke Gong Jin-Yuan Liao Yan-Qiu Zhang Yue Huang Lu Li Xing Wen Fei Zhang Jing Duan Chen-wei Wang Dong-Li Shi Peng Zhang Qi-Bin Yi Chao-Yang Li Yan-Bing Xu Xiao-Hua Liang Ya-Qing Liu Da-Li Zhang Xi-Lei Sun Fan Zhang Gang Chen Huan-Yu Wang Sheng Yang Xiao-Jing Liu Min Gao Mao-Shun Li Jin-Zhou Wang Xing Zhou Yi Zhao Wang-Chen Xue Chao Zheng jia-Cong Liu Xing-Bo Han Jin-Ling Qi jia Huang Ke-Ke Zhang Can Chen Xiong-Tao Yang Dong-Jie Hou Yu-Sa Wang Rui Qiao Xiang Ma Xiao-Bo Li Ping Wang Xin-Ying Song Li-Ming Song Shi-Jie Zheng Bing Li Hong-Mei Zhang Yue Zhu wei Chen jian-jian He Zhen Zhang Jin Hou Hong-Jun Wang Yan-Chao Hao Xiang-Yu Wang Zong-Yuan Yang Zhi-Long Wen Zhi Chang Yuan-Yuan Du Rui Gao Xiao-Fei lan Yan-Guo Li Gang Li Xu-Fang Li Fang-Jun Lu Hong Lu Bin Meng Feng Shi Hui Wang Hui-Zhen Wang Yu-Peng Xu jia-wei Yang Xue-Juan Yang Shuang-Nan Zhang Chao-Yue Zhang Cheng-Mo Zhang Zhi-Cheng Tang Cheng Cheng Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese academy of sciences Chinese Academy of SciencesBeijing 100049China School of Information Science and Technology Southwest Jiaotong UniversityChengdu 611756China Key Laboratory of Stellar and Interstellar Physics and Department of Physics Xiangtan UniversityXiangtan 411105China Physics and Space Science College China West Normal UniversityNanchong 637002China Department of Astronomy Beijing Normal UniversityBeijing 100875China Innovation academy for Microsatellites of CAS Shanghai 201203China Changchun University of Science and Technology Changchun 130022China chinese academy of sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China

Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2020 December *** developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic *** onboard software has the following features:high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation,dedicated localization algorithm optimized for both short and long bursts,and low time latency of the trigger information which is downlinked through the Global Short Message Communication service of the global BeiDou navigation *** paper provides a detailed description of the design and development of the trigger and localization software system for *** covers the general design,workflow,the main functions,and the algorithms used in the *** paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube,as well as an overview of the performance for real celestial bursts during its in-orbit operation.

关键词： telescopes instrumentation:detectors methods:observational

ASAS J174406+2446.8 is identified as a marginal-contact binary with a possible cool third body

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第6期20卷 265-272页

作者： Xiang-Dong Shi Sheng-Bang Qian Lin-jia Li wei-wei Na Xiao Zhou yunnan observatories Chinese Academy of SciencesKunming 650216China University of chinese academy of sciences Beijing 100049China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China Yuxi Normal University Yuxi 653100China

ASAS J174406+2446.8 was originally found as aδScuti-type pulsating star with the period P=0.189068 d by ASAS ***,the LAMOST stellar parameters reveal that it is far beyond the red edge of pulsational instability strip on the log g-T diagram ofδScuti pulsating *** understand the physical properties of the variable star,we observed it by the 1.0-m Cassegrain reflecting telescope at yunnan ***-color light curves in B,V,R_c and I_c bands were obtained and are analyzed by using the W-D *** is found that this variable star is a shallow-contact binary with an EB-type light curve and an orbital period of 0.3781 d rather than aδScuti *** is a W-subtype contact binary with a mass ratio of 1.135(±0.019)and a fill-out factor of 10.4%(±5.6)%.The situation of ASAS J174406+2446.8 resembles those of other EB-type marginal-contact binaries such as UU Lyn,ⅡPer and GW *** of them are at a key evolutionary phase from a semi-detached configuration to a contact system predicted by the thermal relaxation oscillation *** linear ephemeris was corrected by using 303 new determined times of light *** is detected that the O-C curve shows a sinusoidal variation that could be explained by the light-travel-time effect via the presence of a cool red *** present investigation reveals that some of theδScuti-type stars beyond the red edge of pulsating instability strip on the log g-T diagram are misclassified eclipsing *** understand their structures and evolutionary states,more studies are required in the future.

关键词： stars binaries close-stars binaries eclipsing-stars δScuti-stars individual(ASAS J174406+2446.8)

Stellar parameters of main sequence turn-off star candidates observed with LAMOST and Kepler

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2017年第1期17卷 55-70页

作者： Ya-Qian Wu Mao-Sheng Xiang Xian-Fei Zhang Tan-Da Li Shao-lan Bi Xiao-wei Liu jian-Ning Fu Yang Huang Zhi-jia Tian Kang Liu Zhi-Shuai Ge Xin He Jing-Hua Zhang Department of Astronomy Beijing Normal University national astronomical observatories Chinese Academy of Sciences Department of Astronomy Peking University

Main sequence turn-off （MSTO） stars since their ages can be robustly estimated from have advantages as indicators of Galactic evolution atmospheric parameters. Hundreds of thousands of MSTO stars have been selected from the LAMOST Galactic survey to study the evolution of the Galaxy, and it is vital to derive accurate stellar parameters. In this work, we select 150 MSTO star candidates from the MSTO star sample of Xiang that have asteroseismic parameters and determine accurate stellar parameters for these stars by combining asteroseismic parameters deduced from Kepler photometry and atmospheric parameters deduced from LAMOST spectra. With this sample, we examine the age determination as well as the contamination rate of the MSTO star sample. A comparison of age between this work and Xiang shows a mean difference of 0.53 Gyr （7%） and a dispersion of 2.71 Gyr （28%）. The results show that 79 of the candidates are MSTO stars, while the others are contaminations from either main sequence or sub-giant stars. The contamination rate for the oldest stars is much higher than that for younger stars. The main cause for the high contamination rate is found to be the relatively large systematic bias in the LAMOST surface gravity estimates.

关键词： stars: fundamental parameters - stars evolution - stars asteroseismology

Einstein Probe discovery of EP240408a:A peculiar X-ray transient with an intermediate timescale

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2024年

作者： Wenda Zhang weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei Hu Shumei jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P. U. Fynbo Lluis Galbany Saurabh W. Jha Shuaiqing jiang Albert Kong Erik Kuulkers weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen wei Chen Yehai Chen Yifan Chen Chenzhou Cui weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang jia Huo Zhenqing jia Bowen jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu Huaqiu Liu Fangjun Lu Laidan Luo jia Ma Xuan Mao Haiwu Pan Xin Pan Liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck Institute for Extraterrestrial Physics Innovation academy for Microsatellites chinese academy of sciences Department of Physics University of Hong Kong School of Physics and Astronomy University of Leicester School of Physics and Astronomy Sun Yat-sen University national astronomical observatories Department of Physics Anhui Normal University Shanghai Institute of Technical Physics chinese academy of sciences Physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of Physics and Astronomy University of Nevada Las Vegas chinese academy of sciences South African astronomical observatory Department of Astronomy University of Cape Town Department of Physics University of the Free State Universite' Paris Cite' CNRS Astroparticule et Cosmologie Universite' Paris Cite' CEA Paris-Saclay School of Astronomy and Space sciences IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr Institute University of Copenhagen Department of Physics and Astronomy Rutgers the State University of New Jersey Institute for Cosmic Ray Research University of chinese academy of sciences The University of Tokyo ESA/ESTEC Noordwijk 2201 AZ The Netherlands Department of Astronomy School of Physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney Institute for Astronomy School of Physics Key Laboratory of Particle Astrophysics The University of Sydney Department of Astronomy Xiamen University Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Department of Astronomy University of Science and Technology Hefei School of Astronomy and Space sciences University of Science and Technology of china Institute of High Energy Physics Institute of Deep Space sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy yunnan University Shanghai astronomical observatory chinese academy of Science

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 keV,300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 keV,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for4d,followed by a steep decay till becoming undetectable10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词：

Binary Star Fractions from the LAMOST DR4

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2018年第5期18卷 47-58页

作者： Zhi-jia Tian Xiao-wei Liu Hai-Bo Yuan Bing-Qiu Chen Mao-Sheng Xiang Yang Huang Chun Wang Hua-wei Zhang Jin-Cheng Guo Juan-Juan Ren Zhi-Ying Huo Yong Yang Meng Zhang Shao-lan Bi Wu-Ming Yang Kang Liu Xian-Fei Zhang Tan-Da Li Ya-Qian Wu Jing-Hua Zhang Department of Astronomy Peking University Beijing 100871 China Department of Astronomy Beijing Normal University Beijing 100875 China national astronomical observatories Chinese Academy of Sciences Beijing 100101 China Department of Astronomy Yunnan University Kunming 650091 China

Stellar systems composed of single, double, triple or higher-order systems are rightfully regarded as the fundamental building blocks of the Milky Way. Binary stars play an important role in formation and evolution of the Galaxy. Through comparing the radial velocity variations from multiepoch observations, we analyze the binary fraction of dwarf stars observed with LAMOST. Effects of different model assumptions, such as orbital period distributions on the estimate of binary fractions,are investigated. The results based on log-normal distribution of orbital periods reproduce the previous complete analyses better than the power-law distribution. We find that the binary fraction increases with Teff and decreases with [Fe/H]. We first investigate the relation between α-elements and binary fraction in such a large sample as provided by LAMOST. The old stars with high [α/Fe] dominate with a higher binary fraction than young stars with low [α/Fe]. At the same mass, earlier forming stars possess a higher binary fraction than newly forming ones, which may be related with evolution of the Galaxy.

关键词： binaries general- binaries spectroscopic - Galaxy stellar content - stars statistics- surveys

Mapping the emission line strengths and kinematics of supernova remnant S147 with extensive LAMOST spectroscopic observations

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9期18卷 63-78页

作者： Juan-Juan Ren Xiao-wei Liu Bing-Qiu Chen Mao-Sheng Xiang Hai-Bo Yuan Yang Huang Hua-wei Zhang Chun Wang Zhi-jia Tian Gao-Chao Liu Hong Wu Department of Astronomy Peking University Key Laboratory of Optical Astronomy National Astronomy Observatories Chinese Academy of Sciences Kavli Institute for Astronomy and Astrophysics Peking University South-Western Institute for Astronomy Research Yunnan University Department of Astronomy Beijing Normal University College of Science China Three Gorges University

We present extensive spectroscopic observations of supernova remnant （SNR） S 147 collected with the Large sky Area Multi-Object fiber Spectroscopic Telescope （LAMOST）. The spectra were care- fully sky-subtracted taking into account the complex filamentary structure of S 147. We have utilized all available LAMOST spectra toward S 147, including sky and stellar spectra. By measuring the prominent optical emission lines including Ha, [NII] ）λ 6584 and [S n] λλ6717, 6731, we present maps of radial velocity and line intensity ratio covering the whole nebula of S 147 with unprecedented detail. The maps spatially correlate well with the complex filamentary structure of S147. For the central 2° of S147, the radial velocity varies from - 100 to 100 krn s^-1 and has peaks between - 0 and 10 km s^-1. The intensity ratios of Hα/[S n）λλ6717,6731, [Sn] λ 6717/λ 6731 and Ha/IN Hα/λ 6584 peak at about 0.77, 1.35 and 1.48, respectively, with a scatter of 0.17, 0.19 and 0.37, respectively. The intensity ratios are consistent with the literature values. However, the range of variations of line intensity ratios estimated here, which are representative of the whole nebula, is larger than previously estimated.

关键词： ISM supernova remnants - ISM kinematics and dynamics - ISM general