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Spin Evolution of the Magnetar SGR J1935+2154

Research in Astronomy and Astrophysics 2024年第1期24卷 201-211页

作者： Ming-Yu Ge Yuan-Pei Yang Fang-Jun Lu Shi-Qi Zhou Long Ji Shuang-Nan Zhang Bing Zhang Liang Zhang Pei Wang kejia lee Weiwei Zhu Jian Li Xian Hou Qiao-Chu Li Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China South-Western Institute For Astronomy Research Yunnan UniversityKunming 650504China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China Key Laboratory of Stellar and Interstellar Physics and School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China School of Physics and Astronomy Sun Yat-Sen UniversityZhuhai 519082China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China Nevada Center for Astrophysics University of NevadaLas VegasNV 89154USA Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Department of Astronomy Peking UniversityBeijing 100871China CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Yunnan Observatories Chinese Academy of SciencesKunming 650216China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Key laboratory of Modern Astronomy and Astrophysics Nanjing UniversityNanjing 210023China

Fast radio bursts(FRBs)are short pulses observed in radio frequencies usually originating from cosmological *** discovery of FRB 200428 and its X-ray counterpart from the Galactic magnetar SGR J1935+2154suggests that at least some FRBs can be generated by ***,the majority of X-ray bursts from magnetars are not associated with radio *** fact that only in rare cases can an FRB be generated raises the question regarding the special triggering mechanism of *** we report long time spin evolution of SGR J1935+2154 until the end of *** to v and v,the spin evolution of SGR J1935+2154 could be divided into two *** first stage evolves relatively steady evolution until 2020 April *** the burst activity in2020,the spin of SGR J1935+2154 shows strong variations,especially for *** the burst activity in 2022October,a new spin-down glitch with△v/v=(-7.2±0.6)×10^(-6)is detected around MJD 59876,which is the second event in SGR J1935+*** the end,spin frequency and pulse profile do not show variations around the time of FRB 200428 and radio bursts 221014 and 221021,which supply strong clues to constrain the trigger mechanism of FRBs or radio bursts.

关键词： (stars:)pulsars:general (stars:)pulsars:individual(SGR J1935+2154) X-rays:bursts

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Advancing pulsar science with the FAST

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Science China(Physics,Mechanics & Astronomy) 2020年第2期63卷 156-158页

作者： JiGuang Lu kejia lee RenXin Xu CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Guizhou Radio Astronomy Observatory Chinese Academy of SciencesGuiyang 550025China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Department of Astronomy School of PhysicsPeking UniversityBeijing 100871China

As the rump left behind after an extremely gravity-induced supernova of an evolved massive star,a pulsar is made of cool CBM(i.e.,compressed baryonic matter at a low temperature).Pulsars are not only testbeds for fundamental interactions(e.g.,the nature of gravity[1]and of the strong force at low energies[2]),but also essential tools for detecting nanoHz gravitational waves[3].The pulsar science,whatever,usually depends on the measurement of pulsar radiation,e.g.,pulsar monitoring and ***,searching new pulsars for further investigation is also an important focus of this research *** have a very good showing,and have never stopped presenting surprises since the first discovery in 1967,because of the continuing development of advanced facilities.

关键词： pulsar massive FAST

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Repeating fast radio bursts: Coherent circular polarization by bunches

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Science China(Physics,Mechanics & Astronomy) 2022年第8期65卷 148-157页

作者： Wei-Yang Wang Jin-Chen Jiang Jiguang Lu Heng Xu Jiangwei Xu kejia lee Jifeng Liu Renxin Xu School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing100871China CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing100101China Guizhou Radio Astronomy Observatory Chinese Academy of SciencesGuiyang550025China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing100049China

Fast radio bursts(FRBs) are millisecond-duration signals that are highly dispersed at distant galaxies. However, the physical origin of FRBs is still unknown. Coherent curvature emission by bunches, e.g., powered by starquakes, has already been proposed for repeating FRBs. It has the nature of understanding narrowband radiation exhibiting time-frequency drifting. Recently, a highly active FRB source, i.e., FRB 20201124A, was reported to enter a newly active episode and emit at least some highly circular-polarized bursts. In this study, we revisit the polarized FRB emission, particularly investigating the production mechanisms of a highly circular polarization(CP) by deriving the intrinsic mechanism and propagative effect. The intrinsic mechanisms of invoking charged bunches are approached with radiative coherence. Consequently, a highly CP could naturally be explained by the coherent summation of outcome waves, generated or scattered by bunches, with different phases and electric vectors. Different kinds of evolutionary trajectories are found on the Poincaré sphere for the bunch-coherent polarization, and this behavior could be tested through future observations. Cyclotron resonance can result in the absorption of R-mode photons at a low altitude region of the magnetosphere, and an FRB should then be emitted from a high-altitude region if the waves have strong linear polarization. Circularly polarized components could be produced from Faraday conversion exhibiting a λ-oscillation, but the average CP fraction depends only on the income wave, indicating a possibility of a highly circular-polarized income wave. The analysis could be welcome if extremely high(e.g., almost 100%) CP from repeating FRBs is detected in the future. Finally, the production of a bulk of energetic bunches in the pulsar-like magnetosphere is discussed, which is relevant to the nature of the FRB central engine.

关键词： fast radio burst radiation mechanism neutron stars

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Measuring clock jumps using pulsar timing

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Science China(Physics,Mechanics & Astronomy) 2020年第1期63卷 112-117页

作者： ZhiXuan Li kejia lee Ricardo Nicolaos Caballero YongHua Xu LongFei Hao Min Wang JianCheng Wang Yunnan Observatories Chinese Academy of SciencesKunming 650216China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China

In this paper,we investigate the statistical signal-processing algorithm to measure the instant local clock jump from the timing data of multiple *** algorithm is based on the framework of Bayesian *** order to make the Bayesian algorithm applicable with limited computational resources,we dedicated our efforts to the analytic marginalization of irrelevant *** found that the widely used parameter for pulsar timing systematics,the"Efac"parameter,can be analytically *** reduces the Gaussian likelihood to a function very similar to the Student’s *** iterative method to solve the maximum likelihood estimator is also explained in the *** pulsar timing data from the Yunnan Kunming 40-m radio telescope,we demonstrate the application of the method,where 80-ns level precision for the clock jump can be *** a precision is comparable to that of current commercial time transferring service using *** expect that the current method could help developing the autonomous pulsar time scale.

关键词： pulsars time series analysis clocks and frequency standards

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The Qitai radio telescope

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Science China(Physics,Mechanics & Astronomy) 2023年第8期66卷 150-161页

作者： Na Wang Qian Xu Jun Ma Zhiyong Liu Qi Liu Hailong Zhang Xin Pei Maozheng Chen Richard N.Manchester kejia lee Xingwu Zheng Hans J.Kärcher Wulin Zhao Hongwei Li Dongwei Li Martin Süss Matthias Reichert Zhongyi Zhu Congsi Wang Mingshuai Li Rui Li Ning Li Guljaina Kazezkhan Wenming Yan Gang Wu Lang Cui Ming Zhang Haitao Li Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China Xinjiang Key Laboratory of Radio Astrophysics Urumqi 830011China Xinjiang Key Laboratory of Microwave Technology Urumqi 830011China Australia Telescope National Facility CSIRO Space and AstronomyEpping 1710Australia Department of Astronomy Peking UniversityBejing 100871China School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Dr.Hans Jirgen Karcher Engineering Office Karben 61184Germany Northwest China Research Institute of Electronic Equipment Xi'an 710065China OHB Digital Connect(MT Mechatronics) Mainz 55130Germany Beijing Institute of Architetural Design Beijing 100045China Guangzhou Instiute of Technology Xidian UniversityGuangzhou 510555 China

This study presents a general outline of the Qitai radio telescope(QTT)***,the site of the telescope,is a county of Xinjiang Uygur Autonomous Region of China,located in the east Tianshan Mountains at an elevation of about 1800 *** QTT is a fully steerable,Gregorian-type telescope with a standard parabolic main reflector of 110 m *** QTT has adopted an umbrella support,homology-symmetric lightweight *** main reflector is active so that the deformation caused by gravity can be *** structural design aims to ultimately allow high-sensitivity observations from 150 MHz up to115 *** satisfy the requirements for early scientific goals,the QTTwill be equipped with ultra-wideband receivers and large field-of-view multi-beam receivers.A multi-function signal-processing system based on RFSo C and GPU processor chips will be *** will enable the QTT to operate in pulsar,spectral line,continuum and Very Long Baseline Interferometer(VLBI)observing *** compatibility(EMC)and radio frequency interference(RFI)control techniques are adopted throughout the system *** QTT will form a world-class observational platform for the detection of lowfrequency(nano Hertz)gravitational waves through pulsar timing array(PTA)techniques,pulsar surveys,the discovery of binary black-hole systems,and exploring dark matter and the origin of life in the *** QTT will also play an important role in improving the Chinese and international VLBI networks,allowing high-sensitivity and high-resolution observations of the nuclei of distant galaxies and gravitational lensing *** astrometric observations will also contribute to improving the accuracy of the celestial reference ***,the QTT will be able to support future space activities such as planetary exploration in the solar system and to contribute to the search for extraterrestrial intelligence.

关键词： radio telescope radio astronomy observation receiver RFI

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The Gravitational-wave physics Ⅱ: Progress

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Science China(Physics,Mechanics & Astronomy) 2021年第12期64卷 18-67页

作者： Ligong Bian Rong-Gen Cai Shuo Cao Zhoujian Cao He Gao Zong-Kuan Guo kejia lee Di Li Jing Liu Youjun Lu Shi Pi Jian-Min Wang Shao-Jiang Wang Yan Wang Tao Yang Xing-Yu Yang Shenghua Yu Xin Zhang CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Department of Astronomy Beijing Normal UniversityBeijing 100875China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100080China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory for Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study(HIAS)University of Chinese Academy of SciencesHangzhou 310024China MOE Key Laboratory of Fundamental Physical Quantities Measurements Hubei Key Laboratory of Gravitation and Quantum PhysicsNational Precise Gravity Measurement Facility(PGMF)Department of Astronomy and School of PhysicsHuazhong University of Science and TechnologyWuhan 430074China Asia Pacific Center for Theoretical Physics Pohang 37673Korea Department of Physics College of SciencesNortheastern UniversityShenyang 110819China Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University) Ministry of EducationShenyang 110819China Department of Physics Chongqing UniversityChongqing 401331China

It has been a half-decade since the first direct detection of gravitational waves, which signifies the coming of the era of the gravitational-wave astronomy and gravitational-wave cosmology. The increasing number of the detected gravitational-wave events has revealed the promising capability of constraining various aspects of cosmology, astronomy, and gravity. Due to the limited space in this review article, we will briefly summarize the recent progress over the past five years, but with a special focus on some of our own work for the Key Project "Physics associated with the gravitational waves" supported by the National Natural Science Foundation of China. In particular,(1) we have presented the mechanism of the gravitational-wave production during some physical processes of the early Universe, such as inflation, preheating and phase transition, and the cosmological implications of gravitational-wave measurements;(2) we have put constraints on the neutron star maximum mass according to GW170817 observations;(3) we have developed a numerical relativity algorithm based on the finite element method and a waveform model for the binary black hole coalescence along an eccentric orbit.

关键词： gravitational wave gravitational-wave cosmology gravitational-wave astronomy numerical relativity

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Searching for the Nano-Hertz Stochastic Gravitational Wave Background with the Chinese Pulsar Timing Array Data ReleaseⅠ

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Research in Astronomy and Astrophysics 2023年第7期23卷 300-311页

作者： Heng Xu Siyuan Chen Yanjun Guo Jinchen Jiang Bojun Wang Jiangwei Xu Zihan Xue RNicolas Caballero Jianping Yuan Yonghua Xu Jingbo Wang Longfei Hao Jingtao Luo kejia lee Jinlin Han Peng Jiang Zhiqiang Shen Min Wang Na Wang Renxin Xu Xiangping Wu Richard Manchester Lei Qian Xin Guan Menglin Huang Chun Sun Yan Zhu National Astronomical Observatory Chinse Academy of SciencesBeijing 100101China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Department of Astronomy School of PhysicsPeking UniversityBeijing 100871China Max-Planck institut fúr Radioastronomie Auf Dem HúgelBonnD-53121Germany Hellenic Open University School of Science and Technology26335 PatrasGreece Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Yunnan Astronomical Observatories Chinese Academy of SciencesKunming 650216China Institute of Optoelectronic Technology Lishui UniversityLishui 323000China National Time Service Center Chinese Academy Of SciencesXi'an 710600China Key Laboratory of Radio Astronomy and Technology Chinese Academy of SciencesBeijing 100101China Beijing Laser Acceleration Innovation Center HuairouBeijing 101400China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China Australia Telescope National Facility CSIRO Space and AstronomyP.O.Box 76Epping NSW 1710Australia

Observing and timing a group of millisecond pulsars with high rotational stability enables the direct detection of gravitational waves(GWs).The GW signals can be identified from the spatial correlations encoded in the times-of-arrival of widely spaced *** Chinese Pulsar Timing Array(CPTA)is a collaboration aiming at the direct GW detection with observations carried out using Chinese radio *** short article serves as a“table of contents”for a forthcoming series of papers related to the CPTA Data Release 1(CPTA DR1)which uses observations from the Five-hundred-meter Aperture Spherical radio ***,after summarizing the time span and accuracy of CPTA DR1,we report the key results of our statistical inference finding a correlated signal with amplitude logA_(c)=-14.4_(-2.8)^(+1.0)for spectral index in the range ofα∈[-1.8,1.5]assuming a GW background(GWB)induced quadrupolar *** search for the Hellings–Downs(HD)correlation curve is also presented,where some evidence for the HD correlation has been found that a 4.6σstatistical significance is achieved using the discrete frequency method around the frequency of 14 n *** expect that the future International Pulsar Timing Array data analysis and the next CPTA data release will be more sensitive to the n Hz GWB,which could verify the current results.

关键词： (stars:)pulsars:general gravitational waves methods:statistical methods:observational

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中国大型射电望远镜在引力波探测方面的潜在突破

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中国科学：物理学、力学、天文学 2017年第5期47卷 61-66页

作者：李柯伽袁建平王晶波闫文明袁少男王娜北京大学科维里天文与天体物理研究所北京100871 中国科学院新疆天文台乌鲁木齐830011

中国已经建设、正在建设和将要建设成更多的射电望远镜,本文着眼于讨论这些望远镜在引力波直接探测方面的潜在突破.其中,基于最新的脉冲星噪声参数和望远镜设计指标,计算了使用不同射电望远镜以及他们的组合开展脉冲星测时观测的技术能... 详细信息

中国已经建设、正在建设和将要建设成更多的射电望远镜,本文着眼于讨论这些望远镜在引力波直接探测方面的潜在突破.其中,基于最新的脉冲星噪声参数和望远镜设计指标,计算了使用不同射电望远镜以及他们的组合开展脉冲星测时观测的技术能力,在此基础上进一步计算并讨论了利用这些望远镜开展脉冲星测时阵列的可能性及其引力波探测的能力预期.研究发现,大型望远镜如贵州500m口径球面射电望远镜和计划中的新疆奇台110m全可动望远镜的配合将大幅度提高现有国际脉冲星阵列测时能力,建成这些望远镜之后,极有可能在短期内获得重大突破.

关键词：脉冲星引力波

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