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Scintillation Arc from FRB 20220912A

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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 {3.ng {3.-Rui Niu Jin-Lin Han Di Li Ke-{3. 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-{3.ng 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

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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/{3. 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

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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 3. 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

Binary Star Fractions from the LAMOST DR4

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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-{3. 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

LAMOST medium-resolution spectroscopic survey of binarity and exotic star(LAMOST-MRS-B):Observation strategy and target selection

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chinese Physics B 2023年第1期32卷 56-67页

作者：李蛟李江丹郭彦君韩占文陈雪飞刘超葛宏伟姜登凯李立芳章博刘佳明田浩张昊彤袁海龙崔文元任娟娟蔡靖豪施建荣 Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China yunnan observatories Chinese Academy of SciencesKunming 650011China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Department of Physics Hebei Normal UniversityShijiazhuang 050024China

LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution(R~7500)spectroscopic *** aims at studying the statistical properties(e.g.,binary fraction,orbital period distribution,mass ratio distribution)of binary stars and exotic *** intend to observe about 3.000 stars(10 mag≤Glanned to observe 25 plates around the galactic plane in *** the plates were reduced to 12 in 2019 because of the limitation of *** the same time,two new plates located at the high galactic latitude were added to explore binary properties influenced by the different *** this survey project,we set the identified exotic and low-metallicity stars with the highest observation *** the rest of the selected stars,we gave the higher priority to the relatively brighter stars in order to obtain high quality spectra as many as *** of49129 stars have been obtained in LAMOST-MRS-B field and released in DR8,of which 28828 and 3.75 stars have been visited more than twice and ten times with SNR≥10,*** of the sources are B-,A-,and F-type stars with-0.63.7 identified variable and exotic stars and about 250 stars with[Fe/H]3. spectra of the *** uncertainties of RV achieve about 1 km·s^(-1)and 10 km·s^(-1)for 95%of late-and early-type stars,*** datasets presented in this paper are available at http://***/10.57760/sciencedb.j00113.0003..

关键词： surveys spectroscopy catalogs binary