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Bayesian inference of the crust–core transition density via the neutron-star radius and neutron-skin thickness data 被引量:4
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作者 Wen-Jie Xie Zi-Wei Ma Jun-Hua Guo 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第6期125-133,共9页
In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical method.Uniform and Gau... In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical method.Uniform and Gaussian distributions for the ρ_(t) prior were adopted in the Bayesian approach.It has a larger probability of having values higher than 0.1 fm^(−3) for ρ_(t) as the uniform prior and neutron-star radius data were used.This was found to be controlled by the curvature K_(sym) of the nuclear symmetry energy.This phenomenon did not occur if K_(sym) was not extremely negative,namely,K_(sym)>−200 MeV.The value ofρ_(t) obtained was 0.075_(−0.01)^(+0.005) fm^(−3) at a confidence level of 68%when both the neutron-star radius and neutron-skin thickness data were considered.Strong anti-correlations were observed between ρ_(t),slope L,and curvature of the nuclear symmetry energy.The dependence of the three L-K_(sym) correlations predicted in the literature on crust-core density and pressure was quantitatively investigated.The most probable value of 0.08 fm^(−3) for ρ_(t) was obtained from the L-K_(sym) relationship proposed by Holt et al.while larger values were preferred for the other two relationships. 展开更多
关键词 Crust–core transition density of neutron stars neutron-star radius Neutron-skin thickness Bayesian inference approach L–K_(sym)
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Gravitational Wave Radiation from Newborn Accreting Magnetars 被引量:2
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作者 Quan Cheng Xiao-Ping Zheng +1 位作者 Xi-Long Fan Xi Huang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第2期28-41,共14页
The observed electromagnetic radiation from some long and short gamma-ray bursts,and neutron stars(NSs),and the theoretical models proposed to interpret these observations together point to a very interesting but conf... The observed electromagnetic radiation from some long and short gamma-ray bursts,and neutron stars(NSs),and the theoretical models proposed to interpret these observations together point to a very interesting but confusing problem,namely,whether fall-back accretion could lead to dipole field decay of newborn NSs.In this paper,we investigate the gravitational wave(GW) radiation of newborn magnetars with a fall-back disk formed in both the core-collapse of massive stars and the merger of binary NSs.We make a comparison of the results obtained with and without fall-back accretion-induced dipole-field decay(FADD) involved.Depending on the fall-back parameters,initial parameters of newborn magnetars,and models used to describe FADD,FADD may indeed occur in newborn magnetars.Because of the low dipole fields caused by FADD,the newborn magnetars will be spun up to higher frequencies and have larger masses in comparison with the non-decay cases.Thus the GW radiation of newborn accreting magnetars would be remarkably enhanced.We propose that observation of GW signals from newborn magnetars using future GW detectors may help to reveal whether FADD could occur in newborn accreting magnetars.Our model is also applied to the discussion of the remnant of GW170817.From the post-merger GW searching results of Advanced LIGO and Advanced Virgo we cannot confirm the remnant is a low-dipole-field long-lived NS.Future detection of GWs from GW170817-like events using more sensitive detectors may help to clarify the FADD puzzle. 展开更多
关键词 STARS neutron-stars magnetars-stars magnetic field-gravitational waves
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The Neutron Star to Black Hole Mass Gap in the Frame of the Jittering Jets Explosion Mechanism(JJEM)
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作者 Noam Soker 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第9期213-218,共6页
I build a toy model in the frame of the jittering jets explosion mechanism(JJEM)of core collapse supernovae that incorporates both the stochastically varying angular momentum component of the material that the newly b... I build a toy model in the frame of the jittering jets explosion mechanism(JJEM)of core collapse supernovae that incorporates both the stochastically varying angular momentum component of the material that the newly born neutron star(NS)accretes and the constant angular momentum component,and show that the JJEM can account for the≃2.5–5M⊙mass gap between NSs and black holes(BHs).The random component of the angular momentum results from pre-collapse core convection fluctuations that are amplified by post-collapse instabilities.The fixed angular momentum component results from pre-collapse core rotation.For slowly rotating pre-collapse cores the stochastic angular momentum fluctuations form intermittent accretion disks(or belts)around the NS with varying angular momentum axes in all directions.The intermittent accretion disk/belt launches jets in all directions that expel the core material in all directions early on,hence leaving an NS remnant.Rapidly rotating pre-collapse cores form an accretion disk with angular momentum axis that is about the same as the pre-collapse core rotation.The NS launches jets along this axis and hence the jets avoid the equatorial plane region.Inflowing core material continues to feed the central object from the equatorial plane increasing the NS mass to form a BH.The narrow transition from slow to rapid pre-collapse core rotation,i.e.,from an efficient to inefficient jet feedback mechanism,accounts for the sparsely populated mass gap. 展开更多
关键词 STARS massive-stars neutron-stars black holes-(stars )supernovae general-stars jets
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Predicting Gravitational Waves from Jittering-jets-driven Core Collapse Supernovae
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作者 Noam Soker 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第12期1-6,共6页
I estimate the frequencies of gravitational waves from jittering jets that explode core collapse supernovae(CCSNe)to crudely be 5–30 Hz,and with strains that might allow detection of Galactic CCSNe.The jittering jets... I estimate the frequencies of gravitational waves from jittering jets that explode core collapse supernovae(CCSNe)to crudely be 5–30 Hz,and with strains that might allow detection of Galactic CCSNe.The jittering jets explosion mechanism(JJEM)asserts that most CCSNe are exploded by jittering jets that the newly born neutron star(NS)launches within a few seconds.According to the JJEM,instabilities in the accreted gas lead to the formation of intermittent accretion disks that launch the jittering jets.Earlier studies that did not include jets calculated the gravitational frequencies that instabilities around the NS emit to have a peak in the crude frequency range of 100–2000Hz.Based on a recent study,I take the source of the gravitational waves of jittering jets to be the turbulent bubbles(cocoons)that the jets inflate as they interact with the outer layers of the core of the star at thousands of kilometers from the NS.The lower frequencies and larger strains than those of gravitational waves from instabilities in CCSNe allow future,and maybe present,detectors to identify the gravitational wave signals of jittering jets.Detection of gravitational waves from local CCSNe might distinguish between the neutrino-driven explosion mechanism and the JJEM. 展开更多
关键词 gravitational waves-stars neutron-stars black holes-(stars )supernovae general-stars jets
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Probing into the Possible Range of the U Bosonic Coupling Constants in Neutron Stars Containing Hyperons
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作者 Yan Xu Bin Diao +3 位作者 Yi-Bo Wang Xiu-Lin Huang Xing-Xing Hu Zi Yu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第5期180-189,共10页
The range of the U bosonic coupling constants in neutron star matter is a very interesting but still unsolved problem which has multifaceted influences in nuclear physics,particle physics,astrophysics and cosmology.Th... The range of the U bosonic coupling constants in neutron star matter is a very interesting but still unsolved problem which has multifaceted influences in nuclear physics,particle physics,astrophysics and cosmology.The combination of the theoretical numerical simulation and the recent observations provides a very good opportunity to solve this problem.In the present work,the range of the U bosonic coupling constants is inferred based on the three relations of the mass–radius,mass-frequency and mass-tidal deformability in neutron stars containing hyperons using the GM1,TM1 and NL3 parameter sets under the two flavor symmetries of SU(6)and SU(3)in the framework of the relativistic mean field theory.Combined with observations from PSRs J1614-2230,J0348+0432,J2215-5135,J0952-0607,J0740+6620,J0030-0451,J1748-2446ad,XTE J1739-285,GW170817 and GW190814 events,our numerical results show that the U bosonic coupling constants may tend to be within the range from 0 to 20 GeV^(-2)in neutron star containing hyperons.Moreover,the numerical results of the three relations obtained by the SU(3)symmetry are better in accordance with observation data than those obtained by the SU(6)symmetry.The results will help us to improve the strict constraints of the equation of state for neutron stars containing hyperons. 展开更多
关键词 STARS neutron-stars interiors-stars luminosity function-mass function-stars massive-dense matter-equation of state-gravitational waves
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γ暴研究的重大突破:余辉的发现与观测研究 被引量:8
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作者 黄永锋 《天文学进展》 CSCD 北大核心 1998年第4期330-345,共16页
由于BeppoSAX卫星的独特贡献,最近观测到了若于Υ暴在X射线、光学甚至射电波段上的对应体,一度陷入困境的Υ暴研究再次取得了突破性的进展。目前已经观测到了Υ暴GRB970228持续六个月以上的光学余辉,发现它可能位于一个暗弱的宿主星... 由于BeppoSAX卫星的独特贡献,最近观测到了若于Υ暴在X射线、光学甚至射电波段上的对应体,一度陷入困境的Υ暴研究再次取得了突破性的进展。目前已经观测到了Υ暴GRB970228持续六个月以上的光学余辉,发现它可能位于一个暗弱的宿主星系中;GRB970508的光学余辉有较为复杂的表现,并测出其红移范围0.85<z<2.1。在该暴发生约五、六天之后,还观测到了射电耀发现象。观测上的重大突破比较有力地支持了Υ暴的宇宙学起源及火球模型。 展开更多
关键词 Γ射线 中子星 γ星线天文学 Γ暴
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A Possible Mechanism for the Origin of Ultrastrong Magnetic Field of Magnetars
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作者 白华 彭秋和 罗新炼 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第4期1057-1060,共4页
Growing observations reveal that soft gamma-ray repeaters and anomalous x-ray pulsars are magnetars. Their magnetic fields may achieve 10^14 - 10^15G. We explore the origin of the superstrong magnetic field by conside... Growing observations reveal that soft gamma-ray repeaters and anomalous x-ray pulsars are magnetars. Their magnetic fields may achieve 10^14 - 10^15G. We explore the origin of the superstrong magnetic field by considering the magnetization of the ^3P2 superfluid neutrons inside neutron stars (NSs). By solving the Tolman-Oppenheimer-Volkov equations together with the equation of state adopted by Elgaroy it et al. [Phys. Rev. Lett. 77 (1996) 1428] in the calculation of the neutron pairing gap, we specifically calculate the NS internal structure, the permissible region for ^3P2 superfluid neutrons inside the NS, and the total magnetic moment contributed by the orderly arranged neutron vortexes. The result shows that the induced magnetic field may cover a wide range, which is consistent with the magnetic field predicted by the standard magnetic dipole radiation for pulsar spindown. 展开更多
关键词 ACCRETING neutron-stars SOFT GAMMA-REPEATERS X-RAY SUPERFLUIDITY MATTER EVOLUTION SGR-1806-20 FLARE
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An unexpected X-ray transient favors very stiff neutron-star matter
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作者 Zigao Dai 《Science Bulletin》 SCIE EI CAS CSCD 2019年第20期1474-1475,共2页
Short-duration gamma-ray bursts (SGRBs) are mysterious gamma-ray flashes with durations less than two seconds, which occur at the cosmological distances. Some of them usually not only have very tenuous medium gases an... Short-duration gamma-ray bursts (SGRBs) are mysterious gamma-ray flashes with durations less than two seconds, which occur at the cosmological distances. Some of them usually not only have very tenuous medium gases and old host galaxies but also are in the outskirts of the galaxies, suggesting an origin of binary neutron star (NS) mergers (1)This origin was confirmed undoubtedly thanks to the discoveries of a gravitational wave event namedGW170817 and its electromagnetic counterparts (an SGRB, a multiwavelengthkilo-nova, and a broadband afterglow) [2]. 展开更多
关键词 China AN unexpected X-RAY TRANSIENT favors very STIFF neutron-star MATTER origin
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A magnetar-powered X-ray transient as the aftermath of a binary neutron-star merger
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《Science Foundation in China》 CAS 2019年第2期43-43,共1页
With the support by the National Natural Science Foundation of China and other grants,the research team led by Prof.Xue YongQuan(薛永泉)at the Department of Astronomy,University of Science and Technology of China,disc... With the support by the National Natural Science Foundation of China and other grants,the research team led by Prof.Xue YongQuan(薛永泉)at the Department of Astronomy,University of Science and Technology of China,discovered the first X-ray transient that was powered by a magnetar formed during a binary neutron-star merger,which was published in Nature(2019,568:198—201). 展开更多
关键词 Figure A magnetar-powered X-RAY TRANSIENT as the aftermath of a BINARY neutron-star MERGER
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Statistical study of high energy radiation from rotation-powered pulsars
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作者 郑广生 张力 《Science China Mathematics》 SCIE 2000年第2期171-179,共9页
Based on our self-consistent outer gap model for high energy emission from the rotation-powered pulsars, we study the statistical properties of X-ray and y-ray emission from the rotation-powered pulsars, and other sta... Based on our self-consistent outer gap model for high energy emission from the rotation-powered pulsars, we study the statistical properties of X-ray and y-ray emission from the rotation-powered pulsars, and other statistical properties (e.g. diffuse y-ray background and unidentified y-ray point sources) related to y-ray pulsars in our Galaxy and nearby galaxies are also considered. 展开更多
关键词 GAMMA RAYS theory-pulsars general-stars neutron-stars statistics.
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Causal propagation of signals in strangeon matter 被引量:1
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作者 JiGuang Lu EnPing Zhou +1 位作者 XiaoYu Lai RenXin Xu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2018年第8期82-88,共7页
The state equation for strangeon matter is very stiff due to the non-relativistic nature of its particles and their repulsive interaction, such that pulsar masses as high as ~ 3M would be expected. However, an adiaba... The state equation for strangeon matter is very stiff due to the non-relativistic nature of its particles and their repulsive interaction, such that pulsar masses as high as ~ 3M would be expected. However, an adiabatic sound speed, cs = √P/ρ, is usually superluminal in strangeon matter, and the dynamic response of a strangeon star (e.g., binary merger) is not tractable in numerical simulations. In this study, we examined signal propagation in strangeon matter and calculate the actual propagation speed, Csignal. We found that the causality condition, Csignal 〈 c, is satisfied and the signal speed is presented as a function of stellar radius. 展开更多
关键词 equations of state of neutron-star matter acoustic signal processing control theory
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Stellar structure of magnetars
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作者 JianMin Dong Wei Zuo +1 位作者 JianZhong Gu XinLe Shang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2016年第4期66-70,共5页
Magnetars are strong magnetized neutron stars which could emit quiescent X-ray, repeating burst of soft gamma ray, and even the giant flares. We investigate the effects of magnetic fields on the structure of isolated ... Magnetars are strong magnetized neutron stars which could emit quiescent X-ray, repeating burst of soft gamma ray, and even the giant flares. We investigate the effects of magnetic fields on the structure of isolated magnetars. The stellar structure together with the magnetic field configuration can be obtained at the same time within a self-consistent procedure. The magnetar mass and radius are found to be weakly enhanced by the strong magnetic fields. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars. 展开更多
关键词 neutron stars magnetic and electric fields equations of state of neutron-star matter
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