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Research in Astronomy and Astrophysics 2024年第6期24卷 227-235页

作者： Xue-Feng Lu Li-Ming Song Ming-Yu Ge Shuang-Nan zhang Jin-Lu Qu Ce Cai cong-zhan liu Cheng-Kui Li Yu-cong Fu Ying-Chen Xu Key Laboratory of Particle Astrophysics Institute of High Energy Physics University of Chinese Academy of Sciences Chinese Academy of Sciences College of Physics and Hebei Key Laboratory of Photophysics Research and Application Hebei Normal University Department of Astronomy Beijing Normal University

In October 2022, the magnetar SGR J1935+2154 entered the active outburst state. During the episode, the InsightHXMT satellite carried out a long observation that lasted for 20 days. More than 300 bursts were detected, and a certain amount of persistent radiation signals were also accumulated. This paper mainly introduces the results of persistent radiation profile folding and period search based on Insight-HXMT data. At the same time, the burst phase distribution characteristics, spectral lag results of burst, the spectral characteristics of zero-lag bursts and the time-resolved spectral evolution characteristics of high-flux bursts are reported. We found that there is no significant delay feature during different energy bands for the bursts of SGR J1935+2154. The observed zero-lag burst does not have a unique spectrum. The time-resolved spectrum of the individual burst has consistent spectral types and spectral parameters at different time periods of the burst. We also find that the burst number phase distribution and the burst photon phase distribution have the same tendency to concentrate in specific regions of the persistent emission profile.

关键词： dense matter magnetic fields radiation mechanisms: general

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

The GeV emission of PSR B1259–63 during its last three periastron passages observed by Fermi-LAT

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Research in Astronomy and Astrophysics 2018年第12期18卷 89-94页

作者： Zhi Chang Shu zhang Yu-Peng Chen Long Ji Ling-Da Kong cong-zhan liu Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Institut fur Astronomie und Astrophysik Kepler Center for Astro and Particle PhysicsEberhard Karls UniversitatSand 172076 TubingenGermany University of Chinese Academy of Sciences Beijing 100049China

PSR B1259–63 is a γ-ray emitting high mass X-ray binary system, in which the compact object is a millisecond pulsar.The system has an orbital period of 1236.7 d and shows peculiar γ-ray flares when the neutron star moves out of the stellar disk of the companion star.The γ-ray flare events were firstly discovered by using Fermi-LAT around the 2010 periastron passage, which was repeated for the 2014 and 2017 periastron passages.We analyze the Fermi-LAT data for all the three periastron passages and found that in each flare the energy spectrum can be represented well by a simple power law.The γ-ray light curves show that in 2010 and 2014 after each periastron there are two main flares,but in 2017 there are four flares including one precursor about 10 d after the periastron passage.The first main flares in 2010 and 2014 are located at around 35 d after the periastron passage, and the main flare in 2014 is delayed by roughly 1.7 d with respect to that in 2010.In the 2017 flare, the source shows a precursor about 10 d after the periastron passage, but the following two flares become weaker and lag behind those in 2010 by roughly 5 d.The strongest flares in 2017 occurred 58 d and 70 d after the periastron passage.These results challenge the previous models.

关键词： binaries:general pulsars:general gamma rays:general

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In-orbit performance of HE onboard Insight-HXMT in the first 5 years

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Radiation Detection Technology and Methods 2023年第1期7卷 3-14页

作者： Xu-Fang Li cong-zhan liu Yi-Fei zhang Xiao-Bo Li Zheng-Wei Li Xue-Feng Lu Zhi Chang Ming-Yu Ge Juan zhang Yu-Peng Xu Fang-Jun Lu Li-Ming Song Shuang-Nan zhang Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of Science19B Yuquan RoadShijingshan DistrictBeijing 100049China

Purpose The high-energy X-ray telescope(HE),one of the three main payloads of the Insight-HXMT mission,is composed of eighteen NaI(Tl)/CsI(Na)phoswich detectors,where NaI(Tl)serves as the primary detector covering 20–250 keV,and CsI(Na)is used as an active shield detector to suppress the background of NaI(Tl)and also serves as an all-sky gammaray burst monitor covering 0.2–3MeV.In this paper,we review the in-orbit performance of HE in the first 5 years since Insight-HXMT was launched on June 15,2017.Methods The major performances we concern include the gain and energy resolution of NaI(Tl)and CsI(Na)detectors,the performance of pulse shape discriminator(PSD)and system dead time.In this work,we investigate these performances mainly using the data of blank-sky observations and the data when the telescope is in earth occultation.Results The overall performance of HE/NaI(Tl)is very stable in the first 5 years,whereas the gain of HE/CsI(Na)shows a continuously increasing trend and should be calibrated regularly.Conclusion In general,HE is still in good health and well-calibrated status after five-year’s operation.The in-orbit performance of HE has no significant deviation from expectation.HE is expected to be in operation healthily for another several years of extended mission life.

关键词： Insight-HXMT Hard X-ray telescope Scintillation detector In-orbit

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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Probing primordial gravitational waves: Ali CMB Polarization Telescope

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National Science Review 2019年第1期6卷 145-154页

作者： Hong Li Si-Yu Li Yang liu Yong-Ping Li Yifu Cai Mingzhe Li Gong-Bo Zhao cong-zhan liu Zheng-Wei Li He Xu Di Wu Yong-Jie zhang Zu-Hui Fan Yong-Qiang Yao Chao-Lin Kuo Fang-Jun Lu Xinmin zhang Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Theoretical Physics Division Institute of High Energy PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences CAS Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Scienceand Technology of China Interdisciplinary Center for Theoretical Study University of Science and Technology of China National Astronomical Observatories Chinese Academy of Sciences Institute of Cosmology& Gravitation University of Portsmouth Key Laboratory of Particle Astrophysics Institute of High EnergyPhysics Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy Physics ChineseAcademy of Sciences Department of Astronomy School of Physics Peking University Physics Department Stanford University

In this paper, we will give a general introduction to the Ali CMB Polarization Telescope(Ali CPT) project,which is a Sino–US joint project led by the Institute of High Energy Physics and involves many different institutes in China. It is the first ground-based Cosmic Microwave Background(CMB) polarization experiment in China and an integral part of China’s Gravitational-wave Program. The main scientific goal of the Ali CPT project is to probe the primordial gravitational waves(PGWs) originating from the very early Universe. The AliCPT project includes two stages. The first stage, referred to as AliCPT-1, is to build a telescope in the Ali region of Tibet at an altitude of 5250 meters. Once completed, it will be the highest ground-based CMB observatory in the world and will open a new window for probing PGWs in the northern hemisphere. The AliCPT-1 telescope is designed to have about 7000 transition-edge sensor detectors at 95 GHz and 150 GHz. The second stage is to have a more sensitive telescope(Ali CPT-2) with more than 20 000 detectors. Our simulations show that AliCPT will improve the current constraint on the tensor-to-scalar ratio r by one order of magnitude with three years’ observation. Besides the PGWs, Ali CPT will also enable a precise measurement of the CMB rotation angle and provide a precise test of the CPT symmetry. We show that three years’ observation will improve the current limit by two orders of magnitude.

关键词： primordial gravitational waves cosmic microwave background Ali CMB Polarization Telescope

Insight-HXMT on-orbit thermal control status and thermal deformation impact analysis

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Radiation Detection Technology and Methods 2023年第3期7卷 337-349页

作者： Ai-Mei zhang Yi-Fan zhang Jin-Yuan Liao Yu-Peng Xu Yu-Sa Wang Wen-Bo Luo Yu-Peng Zhou Zhi-Ying Qian Xiao-Bo Li Fang-Jun Lu Shuang-Nan zhang Li-Ming Song cong-zhan liu Fan zhang Jian-Yin Nie Juan Wang Sheng Yang Tong zhang Xiao-Jing liu Rui-Jie Wang Xu-Fang Li Yi-Fei zhang Zheng-Wei Li Xue-Feng Lu He Xu Di Wu 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 Beijing Institute of Spacecraft System Engineering CASTBeijing 100094China

Purpose The Hard X-ray Modulation Telescope is China’s first X-ray astronomy satellite launched on June 15,2017,dubbed Insight-HXMT.Active and passive thermal control measures are employed to keep devices at suitable temperatures.In this paper,we analyzed the on-orbit thermal monitoring data of the first 5 years and investigated the effect of thermal deformation on the point spread function(PSF)of the telescopes.Methods We examined the data of the on-orbit temperatures measured using 157 thermistors placed on the collimators,detectors and their support structures and compared the results with the thermal control requirements.The thermal deformation was evaluated by the relative orientation of the two star sensors installed on the main support structure.Its effect was estimated with evolution of the PSF obtained with calibration scanning observations of the Crab nebula.Conclusion The on-orbit temperatures met the thermal control requirements thus far,and the effect of thermal deformation on the PSF was negligible after the on-orbit pointing calibration.

关键词： X-ray Insight-HXMT Thermal control Temperature Star sensor data Pointing PSF

Five-year in-orbit background of Insight-HXMT

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Radiation Detection Technology and Methods 2023年第1期7卷 34-47页

作者： Jin-Yuan Liao Shu zhang Juan zhang Gang Li Zhi Chang Yu-Peng Chen Ming-Yu Ge Jing Jin Xue-Feng Lu Yuan You Xue-Lei Cao Yong Chen Yue Huang Wei-Chun Jiang Xiao-Bo Li Xu-Fang Li Zheng-Wei Li cong-zhan liu Ying Tan Yan-Ji Yang Yi-Fei zhang Hai-Sheng Zhao Fang-Jun Lu Yu-Peng Xu Jin-Lu Qu Li-Ming Song Shuang-Nan zhang Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of Sciences19B Yuquan RoadShijingshan DistrictBeijing 100049China Key Laboratory of Stellar and Interstellar Physics and School of Physics and Optoelectronics Xiangtan UniversityYuhu DistrictXiangtan 411105China University of Chinese Academy of Sciences 19A Yuquan RoadShijingshan DistrictBeijing 100049China Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of Sciences20A Datun RoadChaoyang DistrictBeijing 100012China

Purpose We present the five-year in-orbit background evolution of Insight-HXMT since the launch,as well as the effects of the background model in data analysis.Methods The backgrounds of the three main payloads,i.e.,low-energy telescope,medium-energy telescope,and high-energy telescope,are described.The evolution of the background over time is obtained by simply comparing the background in every year during the in-orbit operation of Insight-HXMT.Results The major observational characteristics of the Insight-HXMT in-orbit background are presented,including the light curve,spectrum,geographical distribution,and long-term evolution.The systematic error in background estimation is investigated for every year.Conclusion The observational characteristics of the five-year in-orbit background are consistent with our knowledge of the satellite design and the space environment,and the background model is still valid for the latest observations of Insight-HXMT.

关键词： Instrumentation:detectors Space vehicles:instruments Methods:data analysis X-rays:general

Iron-Catalyzed Reductive C(aryl)—Si Cross-Coupling of Diaryl Ethers with Chlorosilanes

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Chinese Journal of Chemistry 2024年第6期42卷 578-584页

作者： Pei liu Baowei Wu Xuefeng cong Jie Kong School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi'anShaanxi710072 China Institute of Molecular Plus Department of Chemistry and Haihe Laboratory of Sustainable Chemical TransformationsTianjin University92 Weijin RoadTianjin300072 China

The reductive cross-coupling between C(aryl)—O and Si—Cl bonds is of much importance as a valuable strategy for the construction of C(aryl)—Si bonds but has remained a great challenge.Herein,we report a reductive cross-coupling of diaryl ethers and chlorosilanes via strong electrophilic C(aryl)—O and Si—Cl bonds cleavage by iron catalysis,which constitutes an efficient protocol for the synthesis of a range of functionalized arylsilanes.The combination of low cost FeCl2 as the precatalyst and iPrMgCl as the reductant shows high activity in the successive cleavage of unactivated C(aryl)—O bonds of diaryl ethers and strong electrophilic Si—Cl bonds of chlorosilanes,allowing their cross-coupling in a reductive fashion.The low-valent iron species generated in situ by reduction of FeCl2 with iPrMgCl was proposed,which prefers to initially cleavage the C(aryl)—O bond of diaryl ethers with the chelation help of an o-amide auxiliary.

关键词： Cross-coupling Diaryl ethers Chlorosilanes C—O bond cleavage Iron catalyst 3d transition metals Selectivity Regioselectivity

Effects of vibration conditions,spatial confinement and friction on mixing and segregation characteristics of mixed pebble beds for CFETR WCCB blanket

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Particuology 2024年第2期85卷 268-279页

作者： Yong liu Chongyang He cong Wang Lei Chen Songlin liu Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei230031China University of Science and Technology of China Hefei230027China Chengdu University Chengdu610106China Zhejiang Lab Hangzhou310000China

This paper presents the study of the dynamic characteristics of confined mixed pebble beds with different friction under different vibration conditions using the discrete element method.Theλsegre-gation index is used to quantify the degree of particle mixing or segregation.The percolation,convection and diffusion mechanisms are responsible for the segregation patterns of the mixed pebble.The results show the degree of segregation can be suppressed by decreasing the vibration acceleration or free space height below a threshold.Further simulation reveals the threshold of vibration acceleration or free space height both are related to the bed height increment which determines the strength of the percolation mechanism.In addition,the strength of percolation and convection becomes weaker by decreasing the friction of particles and walls,which makes the pebbled bed remains in a mixed state under vibration.These findings are significant to clarify the main factors behind the three segregation mechanisms and hence provide solutions to retaining the mixed state of the Li2TiO3&Be12Ti mixed pebble bed.

关键词： Vibration Segregation Binary pebble bed Discrete element method