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Timing and Spectral Analysis of the Black Hole X-Ray Binary MAXI J1803-298 with Insight-HXMT Data

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Research in Astronomy and Astrophysics 2024年第6期24卷 211-226页

作者： Ying-Chen Xu Jin-Lu Qu M.Méndez Rui-Can Ma Long Ji Liang Zhang Yue Huang Qing-Cui Bu Li-Ming Song Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Chinese Academy of Sciences Kapteyn Astronomical institute University of Groningen Dongguan Neutron Science Center School of Physics and Astronomy Sun Yat-Sen University institut für astronomie und astrophysik Kepler Center for Astro and Particle Physics Eberhard Karls Universit?t

We present a comprehensive analysis of the 2021 outburst of MAXI J1803–298 utilizing observations of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT) spanning from the low hard state to the high soft state.Within the Insight-HXMT data set, compared to the previous work, we identify a more prolonged presence of typeC quasi-periodic oscillations(QPOs) with centroid frequencies ranging from ～0.16 to 6.3 Hz, which present correlations with the hardness ratio and the photon index of the Comptonized component. For QPO frequencies less than ～2 Hz, the QPO phase lags are hard(photons of 10–19 keV arrive later than those of 1–4 keV), while at higher frequencies, the lags become soft at and above ～4 Hz. furthermore, the spectra in all Insight-HXMT observations consist of a multi-color blackbody component and a Comptonized component, as commonly observed in classical black hole X-ray binaries. We analyze state transitions and the evolution of accretion geometry in this work. The fitted inner disk radius increases abnormally during the low hard state, hypothesized to result from the corona condensing onto the inner disk. Additionally, two significant drops in flux are observed during the soft intermediate state, maybe implying changes in the corona/jet and the disk, respectively.

关键词： accretion accretion disks stars: black holes X-rays: binaries

Berry-Esseen bounds and moderate deviations for the norm, entries and spectral radius of products of positive random matrices

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Science China Mathematics 2024年第3期67卷 627-646页

作者： Hui Xiao Ion Grama Quansheng Liu institut fur Mathematik und Angewandte Informatik Universitat HildesheimHildesheim 31141Germany Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China LMBA Universite Bretagne SudCNRS UMR 6205Vannes F-56000France

Let(g_(n))_(n≥1) be a sequence of independent and identically distributed positive random d×d matrices and consider the matrix product G_(n)=g_(n)…g_1.under suitable conditions,we establish the Berry-Esseen bounds on the rate of convergence in the central limit theorem and Cramer-type moderate deviation expansions,for any matrix norm ‖G_(n)‖ of G_(n),its entries G_(n)^(i,j) and its spectral radius ρ(G_(n)).Extended versions of their joint law with the direction of the random walk G_(n)x are also established,where x is a starting point in the unit sphere of R~d.

关键词： Berry-Esseen bound Cramér-type moderate deviation product of random matrices operator norm entry spectral radius

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

Response optimization of a three-axis sensitive SERF magnetometer for closed-loop operation

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Chinese Physics B 2024年第6期33卷 291-297页

作者：周原锐孙永泽汪茜茜秦佳男张雪王言章 Key Laboratory of Geophysical Exploration Equipment(Ministry of Education) Jilin UniversityChangchun 130012China College of Instrumentation and Electrical Engineering Jilin UniversityChangchun 130012China Department of Physics Johannes Gutenberg-Universitat Mainz55128 MainzGermany Helmholtz-institut GSI Helmholtzzentrum fur Schwerioneforschung55128 MainzGermany

Most triaxial-vectorial magnetic field measurements with spin-exchange relaxation free(SERF)atomic magnetometer(AM)are based on the quasi-steady-state solution of the Bloch equation.However,the responding speed of these methods is greatly limited because the frequency of the modulation signal should be slow enough to ensure the validity of the quasi-steady-state solution.In this work,a new model to describe the response of the three-axis sensitive SERF AM with high modulation frequency is presented and verified.The response of alkali-atomic spin to high-frequency modulation field is further investigated by solving the Bloch equation in a modulation-frequency-dependence manner.This solution is well verified by our experiments and can offer a reference for selection of modulation frequencies.The result shows a potential to achieve a SERF AM operating in a geomagnetic field without heavy aluminum shielding when the modulation frequencies are selected properly.

关键词： triaxial-vectorial magnetic field measurement spin-exchange relaxation free atomic magnetometer

Characteristics of the SOL ion-to-electron temperature ratio on the J-TEXT tokamak with different plasma configurations

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Plasma Science and Technology 2024年第2期26卷 13-21页

作者：李存凯梁云峰江中和周松华建坤阳杰杨庆虎 Alexander KNIEPS Philipp DREWS 徐鑫毛飞越谢伟杨雨桐郭金龙李杨波任正康陈志鹏王能超 the J-TEXT Team International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China Forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung—PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)Julich 52425Germany 不详

Accurate measurement of the average plasma parameters in the edge region,including the temperature and density of electrons and ions,is critical for understanding the characteristics of the scrape-off layer(SOL) and divertor plasma transport in magnetically confined fusion research.On the J-TEXT tokamak,a multi-channel retarding field analyzer(RFA) probe has been developed to study average plasma parameters in the edge region under various poloidal divertor and island divertor configurations.The edge radial profile of the ion-to-electron temperature ratio,τ_(i/e),has been determined,which gradually decreases as the SOL ion self-collisionality,v_(SOL)*,increases.This is broadly consistent with what has been observed previously from various tokamak experiments.However,the comparison of experimental results under different configurations shows that in the poloidal divertor configuration,even under the same v_(SOL)*,τ_(i/e) in the SOL region becomes smaller as the distance from the X-point to the target plate increases.In the island divertor configuration,τ_(i/e) near the O-point is higher than that near the X-point at the same v_(SOL)*,and both are higher than those in the limiter configuration.These results suggest that the magnetic configuration plays a critical role in the energy distributions between electrons and ions at the plasma boundary.

关键词： ion temperature island divertor poloidal divertor retarding field analyzer(RFA)probe

Application of the three-dimensional telegraph equation to cosmic-ray transport

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Research in Astronomy and Astrophysics 2016年第10期16卷 107-115页

作者： Robert C. Tautz Ian Lerche Zentrum fur astronomie und astrophysik Technische Universitat Berlin HardenbergstraBe 36 D-10623 Berlin Germany institut fur Geowissenschaften Naturwissenschaftliche Fakultat Ⅲ Martin-Luther-Universitat Halle D-06099 HalleGermany

An analytical solution to the three-dimensional telegraph equation is presented. This equation has recently received some attention but so far the treatment has been one-dimensional. By using the structural similarity to the Klein-Gordon equation, the telegraph equation can be solved in closed form. Illustrative examples are used to discuss the qualitative differences from the diffusion solution. A comparison with a numerical test-particle simulation reveals that some features of an intensity profile can be better explained using the telegraph approach.

关键词： plasmas -- turbulence -- magnetic field -- diffusion -- solar wind

Spectral and Timing Analysis of the Black Hole Transient MAXI J1631–479 During its 2019 Outburst Observed with Insight-HXMT

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Research in Astronomy and Astrophysics 2022年第11期22卷 21-33页

作者： Yu-Cong Fu L.M.Song G.Q.Ding S.N.Zhang J.L.Qu S.Zhang L.Zhang Q.C.Bu Y.Huang X.Ma Z.X.Yang Y.L.Tuo X.F.Lu D.K.Zhou B.Y.Wu T.M.Li Y.C.Xu Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqiXinjiang 830011China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China 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 1D-72076 TübingenGermany

We report spectral and timing analysis of the black hole transient MAXI J1631–479 during the hard intermediate state of its 2019 outburst from the Insight-Hard X-ray Modulation Telescope(Insight-HXMT)observations.We find that the energy dependence of the type-C quasi-periodic oscillation(QPO)frequency evolves with time:during the initial rise of a small flare(~MJD 58526.0-58527.1),the QPO frequency increases with increasing energy from~1 to~100 ke V,and then the frequency remains constant after MJD 58527.1.We discover a possible new phenomenon of Fe line’s QPO frequency jump that has never been observed for other black hole transients:during the small flare,the QPO frequency around the Fe line energy is higher than any other energy band,with the frequency difference Δf=0.25±0.08 Hz between 5.5–7.5 ke V and other energy bands.The spectral analysis shows that the evolution of QPOs is related to the equivalent width of the narrow Fe line,and its equivalent width increases during this small flare.We propose that the QPO frequency difference results from the differential precession of a vertically extended jet,and the higher QPO frequency of Fe line could be caused by the layered jet when the jet scale increases.At the same time,the evolution of QPOs is related to the accretion rate,while the energy dependence of QPOs supports the existence of deceleration in the vertically distributed jet.

关键词： accretion accretion disks stars:black holes X-rays:binaries

Role of extrusion rate on the microstructure and tensile properties evolution of ultrahigh-strength low-alloy Mg-1.0Al-1.0Ca-0.4Mn(wt.%)alloy

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Journal of Magnesium and Alloys 2023年第2期11卷 553-561页

作者： X.Q.Liu X.G.Qiao R.S.Pei Y.Q.Chi L.Yuan M.Y.Zheng School of Material Science and Engineering Harbin Institute of TechnologyHarbin 150001China institut fur Metallkunde und Meterialphysik RWTH Aachen UniversityAachen D-52056Germany

Mg-1.0Al-1.0Ca-0.4Mn(AXM1104, wt.%) low alloy was extruded at 200 ℃ with an extrusion ratio of 25 and different ram speeds from 1.0 to 7.0 mm/s. The influence of extrusion rate on microstructure and mechanical properties of the AXM1104 alloy was systematically studied. With the increasing of extrusion rate, the mean dynamically recrystallized(DRXed) grain size of the low alloy and average particles diameter of precipitate second phases were increased, while the degree of grain boundary segregation and the intensity of the basal fiber texture were decreased. With the rising of extrusion rate from 1.0 to 7.0 mm/s, the tensile yield strength(TYS) of the as-extruded AXM1104 alloy was decreased from 445 MPa to 249 MPa, while the elongation to failure(EL) was increased from 5.0% to 17.6%. The TYS, ultimate tensile strength(UTS) and EL of the AXM1104 alloy extruded at the ram speed of 1.5 mm/s was 412 MPa, 419 MPa and 12.0%, respectively,exhibiting comprehensive tensile mechanical properties with ultra-high strength and excellent plasticity. The ultra-high TYS of 412 MPa was mainly due to the strengthening from ultra-fine DRXed grains with segregation of solute atoms at grain boundaries. The strain hardening rate is increase slightly with increasing extrusion speed, which may be ascribed to the increasing mean DRXed grain size with rising extrusion speed. The higher strain hardening rate contributes to the higher EL of these AXM1104 samples extruded at higher ram speed.

关键词： Mg-Al-Ca-Mn alloy Ultrafine grain Extrusion rate Grain boundary segregation Microstructure Ultrahigh strength

High-Tc superconductor Fe(Se,Te) monolayer:an intrinsic,scalable and electrically tunable Majorana platform

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National Science Review 2022年第3期9卷 11-18页

作者： Xianxin Wu Xin Liu Ronny Thomale Chao-Xing Liu institut für Theoretische Physik und astrophysik Julius-Maximilians-Universit?t Würzburg School of Physics Huazhong University of Science and Technology Wuhan National High Magnetic Field Center Huazhong University of Science and Technology Department of Physics the Pennsylvania State University

Iron-based superconductors have been identified as a novel platform for realizing Majorana zero modes(MZMs) without heterostructures, due to their intrinsic topological properties and high-Tc superconductivity. In the two-dimensional limit, the FeTe1-xSexmonolayer, a topological band inversion has recently been experimentally observed. Here, we propose to create MZMs by applying an in-plane magnetic field to the FeTe1-xSexmonolayer and tuning the local chemical potential via electric gating.Owing to the anisotropic magnetic couplings on edges, an in-plane magnetic field drives the system into an intrinsic high-order topological superconductor phase with Majorana corner modes. furthermore, MZMs can occur at the domain wall of chemical potentials at either one edge or certain type of tri-junction in the two-dimensional bulk. Our study not only reveals the FeTe1-xSexmonolayer as a promising Majorana platform with scalability and electrical tunability and within reach of contemporary experimental capability,but also provides a general principle to search for realistic realization of high-order topological superconductivity.

关键词： high-order topological superconductivity Majorana zero modes iron-based superconductors