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Searching for the Highest Energy of Pulsation and Critical Luminosity of Swift J0243.6+6124 Observed by Insight-HXMT

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Research in Astronomy and Astrophysics 2024年第5期24卷 61-69页

作者： Qing-Xia Zhao Xian Hou Ming-Yu Ge Shuang-Nan Zhang Yun-Xiang Xiao you-li tuo Zi-Xu Yang ling-Da Kong Jin-Lu Qu Shu Zhang Jian-Cheng Wang Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences ChineseAcademy of SciencesBeijing 100049China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Institut fur Astronomic und Astrophysik Sand 1D-72076 TabingenGemany School of Physics and Optoelectronic Engineering Shandong University of TechnologyZibo 255000China

Owing to the broad energy coverage of Insight-HXMT in the hard X-ray band,we detected the highest energy of pulsation exceeding 200 keV around the 2017–2018 outburst peak of the first Galactic pulsating ultraluminous X-ray source (PULX) Swift J0243.6+6124,which is the highest energy detected from PULXs to date.We also obtained the highest energy of pulsation of every exposure during the outburst in 2017–2018,and found the highest energy is roughly positively correlated with luminosity.Using our newly developed method,we identified the critical luminosity being 4×10~(38)erg s~(-1) when the main peaks of the low and high energy pulse profiles became aligned,which separates the fan-beam dominated and pencil-beam dominated accretion regimes.Above the critical luminosity,the phase of the main peak shifted gradually from 0.5 to 0.8 until the outburst peak in al energy bands is reached,which is in agreement with the phase shift found previously at low energies.Our result is consistent with what is derived from spectral analysis.

关键词： (stars:)pulsars-individual(Swift J0243.6+6124)-X-rays binaries–stars neutron

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The Time and Energy Dependence of the Vela Pulsar's Pulse Profile inγ-Ray

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Research in Astronomy and Astrophysics 2022年第4期22卷 128-136页

作者： lin-li Yan Ming-Yu Ge you-li tuo ling-jun Wang Qing-yong Zhou School of Mathematics and Physics Anhui Jianzhu UniversityHefeiAnhui 230601China Key Laboratory of Architectural Acoustics Environment of Anhui High Education Institutes HefeiAnhui 230601China Key Laboratory of Advanced Electronic Materials and Devices Anhui Jianzhu UniversityHefeiAnhui 230601China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China State Key Laboratory of Geographic Information Engineering Xi'an Institute of Surveying and MappingXi'an 710054China

We analyze the time and energy dependence of the Vela pulsar’s pulse profile using 13 yr observations from the Large Area Telescope on the Fermi Gamma-ray Space Telescope.It is found that the pulse profile of the Vela pulsar inγ-ray changes with time.We parameterize the pulse profile and find that different shape parameters show fiuctuations rather than gradual changes with time.However,these time variation trends are insignificant due to limited statistics.The pulse profile of the Vela pulsar displays clear energy dependence inγ-ray.Different shape parameters are accurately obtained or updated,especially the phase separations among different pulses.Their energy evolution trends are quantified for the first time,which will provide restrictions on currentγ-ray emission models.For the Vela pulsar,we also find a turning point at phase.Before and after this phase,the relative intensity of the pulse profile evolves with energy with the opposite trend.

关键词： stars:neutron (stars:)pulsars:individual(Vela) gamma-rays:stars Pulsars(1306) Gamma-ray sources(633)

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Long-term evolution of the X-ray flux of the Crab pulsar

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Radiation Detection Technology and Methods 2023年第1期7卷 48-55页

作者： Hai-Sheng Zhao Ming-Yu Ge Xiao-Bo li lin-li Yan you-li tuo Fang-Jun Lu li-Ming Song Cong-Zhan liu Shu Zhang Shuang-Nan Zhang Key Laboratory for Particle Astrophysics Institute of High Energy PhysicsChinese Academy of Sciences19B Yuquan RoadBeijing 100049China School of Mathematics and Physics Anhui JianZhu UniversityHefei 230601AnhuiChina

Purpose In order to carry out in-orbit calibration,the hard X-ray modulation telescope satellite(HXMT)has made a number of observations of Crab pulsar.We study the long-term evolution of the X-ray flux of the Crab pulsar with these observational data.Methods We use nearly four years Crab pulsar’s data obtained by HXMT and the neutron star interior composition of explorer to test whether L_(x)∝L_(sd)^(α) holds for an individual pulsar,where L_(x) is the pulsed X-ray luminosity and Lsd is its spin-down luminosity.We also combine the earlier results obtained with PCA and HEXTE data(Yan et al.in ApJ 865:21,2018)to get the long-term evolution characteristics of the Crab pulsar.Results We find the X-ray flux evolution can be fitted by a linear correlation:L_(x)∝L_(sd)^(1.42±0.18).In soft X-ray energy band(1–10 keV)and hard X-ray energy band(27–250 keV),αdoes not change significantly with either energy or phase.However,this will need to be confirmed in future.For example,the interpulse component of hard X-ray may follow L_(x)∝L_(sd)^(0.96±0.34),which may be different from the correlation of soft X-rays and main pulse component.On the other hand,the hard X-ray flux evolution shows that the performance of high energy X-ray telescope(HE)onboard HXMT,such as effective area,is stable.Conclusion We conclude that the X-ray luminosity of the Crab pulsar closely correlates with its spin-down luminosity.However,the emission mechanism responsible for these phenomena remains not fully understood.

关键词： X-rays Crab pulsar Flux evolution Spin-down luminosity

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Burst Phase Distribution of SGR J1935+2154 Based on Insight-HXMT

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Research in Astronomy and Astrophysics 2023年第3期23卷 68-74页

作者： Xue-Feng Lu li-Ming Song Ming-Yu Ge you-li tuo Shuang-Nan Zhang Jin-Lu Qu Ce Cai Sheng-Lun Xie Cong-Zhan liu Cheng-Kui li Yu-Cong Fu Ying-Chen Xu Tian-Ming li Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsBeijing 100049China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China College of Physics and Hebei Key Laboratory of Photophysics Research and Application Hebei Normal UniversityShijiazhuang 050024China Institute of Astrophysics Central China Normal UniversityWuhan 430079China

On 2020 April 27,the soft gamma-ray repeater SGR J1935+2154 entered its intense outburst episode again.Insight-HXMT carried out about one month observation of the source.A total number of 75 bursts were detected during this activity episode by Insight-HXMT,and persistent emission data were also accumulated.We report on the spin period search result and the phase distribution of burst start times and burst photon arrival times of the Insight-HXMT high energy detectors and Fermi/Gamma-ray Burst Monitor(GBM).We find that the distribution of burst start times is uniform within its spin phase for both Insight-HXMT and Fermi/GBM observations,whereas the phase distribution of burst photons is related to the type of a burst’s energy spectrum.The bursts with the same spectrum have different distribution characteristics in the initial and decay episodes for the activity of magnetar SGR J1935+2154.

关键词： spectrum Fermi distribution

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Insight-HXMT observations of the Crab pulsar

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Research in Astronomy and Astrophysics 2019年第6期19卷 109-116页

作者： you-li tuo Ming-Yu Ge li-Ming Song lin-li Yan Qing-Cui Bu Jin-Lu Qu Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of the Chinese Academy of Sciences Beijing 100049 China School of Mathematics and Physics Anhui Jianzhu University Hefei 230601 China

We report on X-ray emission properties of the Crab pulsar(PSR B0531+21) using observations by Insight-HXMT during its first year after launch. We obtained high signal-to-noise profiles in the X-ray energy band 11–250 keV. We have confirmed an increase in the flux ratio of the second peak over the main peak with increasing energy, consistent with other missions. The separation of the two peaks shows no significant trend with increasing energy. The phase-averaged spectrum, fitted by a logpar model, and the phase-resolved spectra of the Crab pulsar, fitted by a powerlaw in the different energy bands of HXMT, are consistent with RXTE and NuSTAR in that photon indices evolve as a function of phase as well as a function of energy, contributing to a broadband modeling.

关键词： stars neutron star-pulsars individual(Crab)-X-rays

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Paired quasi-periodic pulsations of hard X-ray emission in a solar flare

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Science China(Physics,Mechanics & Astronomy) 2023年第5期66卷 195-206页

作者： Hai-Sheng Zhao Dong li Shao-lin Xiong Yan-Qiu Zhang Yang Su Wei Chen Yi Zhao Xiao-Bo li Jia-Cong liu Wen-Xi Peng Rui Qiao Xin-Qiao li Xiang-Yang Wen li-Ming Song Shi-Jie Zheng Xin-Ying Song Xiao-Yun Zhao Yue Huang Shuang-Nan Zhang Shuo Xiao Ce Cai Zheng-Hua An Can Chen Gang Chen Wei Chen Yan-Qi Du Min Gao Ke Gong Dong-Ya Guo Zhi-Wei Guo Jian-Jian He Bin li Chao li Chao-Yang li Gang li Jian-Hui li Lu li Qing-Xin li Yan-Guo li Jing liang Xiao-Hua liang Jin-Yuan liao Xiao-Jing liu Ya-Qing liu Qi Luo Xiang Ma Bin Meng Ge Ou Dong-li Shi Jing-Yan Shi Gong-Xing Sun Xi-Lei Sun you-li tuo Chen-Wei Wang Hui Wang Jin Wang Jin-Zhou Wang Ping Wang Wen-Shuai Wang Hong Wu Sheng-Lun Xie Yan-Bing Xu Yu-Peng Xu Wang-Chen Xue Sheng Yang Min Yao Jian-Ying Ye Qi-Bin Yi Chao-Yue Zhang Da-li Zhang Fan Zhang Fei Zhang Hong-Mei Zhang Kai Zhang Peng Zhang Xiao-Lu Zhang Zhen Zhang Guo-Ying Zhao Shi-Yi Zhao Chao Zheng Xing Zhou Yue Zhu Key Laboratory for Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China University of Chinese Academy of Sciences Beijing 100049China Department of Astronomy Beijing Normal UniversityBeijing 100875China School of Computing and Artificial Intelligence Southwest Jiaotong UniversityChengdu 611756China Physics and Space Science College China West Normal UniversityNanchong 637002China Key Laboratory of Stellar and Interstellar Physics and Department of Physics Xiangtan UniversityXiangtan 411105China Institute of Astrophysics Central China Normal UniversityWuhan 430079China School of Physics Changchun University of Science and TechnologyChangchun 130022China College of Physics and Engineering Qufu Normal UniversityQufu 273165China College of Physics Sciences&Technology Hebei UniversityBaoding 071002China

We investigate high time resolution data obtained by the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)during the flare event on 2022 April 21 at 01:52 UT.Several subpeaks with durations of 4-6 s have been detected in the hard X-ray precursor phase,and the key feature is that they appear in pairs and seem like double-peak struc-tures.These subpeaks are rarely observed in hard X-ray band and confirmed by the microwave obtained by Nobeyama Radio Polarimeters(NoRP)and Radio Solar Telescope Network(RSTN).While an exponential function can describe the continuum component of the time profile from the precursor to part of the impulsive phase.The periods of quasi-periodic pulsations(QPPs)are detected to be about 7.3 and 12.8 s for the precursor and impulsive phase,respectively,with at least 95%confidence level.The paired QPPs are assumed to be double-peak QPPs and then the scenario of current loop coalescence model is found to be in good agreement with our observation.The precursor phase can be interpreted as the oscillating coalescence of two islands,while the impulsive phase can be interpreted as more islands to coalesce one by one to form larger islands.

关键词： solar flare QPPs loop coalescence circular-ribbon flare

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The influence of the Insight-HXMT/LE time response on timing analysis

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Research in Astronomy and Astrophysics 2021年第1期21卷 45-52页

作者： Deng-Ke Zhou Shi-Jie Zheng li-Ming Song Yong Chen Cheng-Kui li Xiao-Bo li Tian-Xiang Chen Wei-Wei Cui Wei Chen Da-Wei Han Wei Hu Jia Huo Rui-Can Ma Mao-Shun li Tian-Ming li Wei li He-Xin liu Bo Lu Fang-Jun Lu Jin-Lu Qu you-li tuo Juan Wang Yu-Sa Wang Bai-Yang Wu Guang-Cheng Xiao Yu-Peng Xu Yan-Ji Yang Shu Zhang Zi-liang Zhang Xiao-Fan Zhao Yu-Xuan Zhu 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 College of Physics Jilin UniversityChangchun 130012China

The LE is the low energy telescope that is carried on Insight-HXMT.It uses swept charge devices(SCDs)to detect soft X-ray photons.LE’s time response is caused by the structure of the SCDs.With theoretical analysis and Monte Carlo simulations we discuss the influence of LE time response(LTR)on the timing analysis from three aspects:the power spectral density,the pulse profile and the time lag.After the LTR,the value of power spectral density monotonously decreases with the increasing frequency.The power spectral density of a sinusoidal signal reduces by a half at frequency 536 Hz.The corresponding frequency for quasi-periodic oscillation(QPO)signals is 458 Hz.The root mean square(RMS)of QPOs holds a similar behaviour.After the LTR,the centroid frequency and full width at half maxima(FWHM)of QPOs signals do not change.The LTR reduces the RMS of pulse profiles and shifts the pulse phase.In the time domain,the LTR only reduces the peak value of the cross-correlation function while it does not change the peak position;thus it will not affect the result of the time lag.When considering the time lag obtained from two instruments and one among them is LE,a 1.18 ms lag is expected caused by the LTR.The time lag calculated in the frequency domain is the same as that in the time domain.

关键词： instrumentation:detectors methods:data analysis methods:analytical

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Two-way shape memory effect in a Ti-Zr-Nb-Ta high-temperature shape memory alloy

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Rare Metals 2024年第3期43卷 1257-1262页

作者： Cheng-Yang Xiong tuo li Jun Wang Yan li School of Materials Science and Engineering Beihang UniversityBeijing100191China

The two-way shape memory effect in a Ti-18.5Zr-10Nb-3.5Ta high-temperature shape memory alloy was investigated.X-ray diffraction measurem ent shows that the alloy is composed of orthorhombicα"-martensite.ωphase is not found in Ti-18.5Zr-10Nb-3.5Ta alloy due to the suppressing effect of Ta element.Theα"-martensite laths are found in the transmission electron microscope observation;after the bending deformation,there appear a lot of dislocations.The alloy exhibits a shape memory strain of 3.8%aud a high reverse martensite transformation start temperature of 464 K.The maximum two-way shape memory strain of 1.2%is obtained in the alloy with the prebending training strain of 10%.The mechanism can be ascribed to the effect of internal stress field caused by dislocations.

关键词： Ti-Zr Shape memory alloys Two-way shape memory effect

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Simultaneously enhancing the strength and ductility of as-extruded AlN/AZ91 composites via nano-precipitation and pyramidal slip

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Journal of Materials Science & Technology 2024年第5期172卷 240-254页

作者： Bin Zhang Yunxia Sun tuo liang Yunzhen li Tian li Jingchao Wang Ruiru Cai Changlin Yang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

Age hardening is often used to optimize the mechanical properties of as-deformed Mg-based materials in industry,whereas the improvement of strength is usually accompanied by the significant loss of ductility,which hinders the application of Mg-based materials in structural components.In the present work,high strength-ductility synergy(the yield strength of 263±9 MPa,ultimate tensile strength of 398±7 MPa and elongation to fracture of 34%±1%)was realized in as-extruded AlN/AZ91 composites after optimiz-ing aging processes.Microstructural characterization shows that AlN particles induced a large number of geometrically necessary dislocations around the AlN/Mg interface during extrusion,which decreased the nucleation barrier and provided more heterogeneous nucleation sites forγ-Mg 17 Al 12 continuous precipi-tation.Meanwhile,95%of residual dislocations in as-extruded AlN/AZ91 composites were annihilated dur-ing peak-aging,suppressing the growth and coarsening of continuous precipitates.Therefore,high density of nano-sizedγ-Mg 17 Al 12 continuous precipitates was produced in as-extruded AlN/AZ91 composites af-ter peak-aging.During tension,gliding dislocations bypassed sphericalγ-Mg 17 Al 12 nano-precipitates by Orowan looping rather than cutting mechanism,which induced a strong block on dislocation motion.So high yield strength was mainly attributed to the high density of non-shearableγ-Mg 17 Al 12 nano-precipitates with spherical morphology,which was different from other Mg-Al-based systems.The results of texture evolution and slip trace analysis demonstrated that the suppression of extension twinning and less basal slip was due to the enhanced activity of pyramidalc+aslip in as-extruded AlN/AZ91 com-posites after peak-aging during the room temperature tension,meanwhile,the dislocation density of as-extruded AlN/AZ91 composites was significantly decreased during peak-aging,then higher elongation to fracture was achieved.

关键词： Magnesium matrix composites Mechanical properties Precipitation Deformation mechanisms Non-basal slip

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An analysis of TinyML@ICCAD for implementing AI on low-power microprocessor

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Science China(Information Sciences) 2024年第4期67卷 343-344页

作者： Guoqing li Jingwei ZHANG Meng ZHANG tuo li Tinghuan CHEN Jun YANG Shandong Yunhai Guochuang Cloud Computing Equipment Industry Innovation Co. Ltd. School of Integrated Circuits Southeast University Shandong Inspur Artificial Intelligence Research Institute Co. Ltd. School of Science and Engineering The Chinese University of Hong Kong

Tiny machine learning(ML) is an important application area of artificial intelligence(AI), which focuses on deploying AI on small hardware platforms with constrained resources [1, 2]. The high-level TinyML contests at high-level conferences promote the development of TinyML areas, such as DAC-SDC [3] and TinyML@ICCAD [4].

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