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Extracting Energy Magnetically from Plunging Region of Black-Hole accretion disk

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Communications in Theoretical Physics 2007年第2期47卷 374-378页

作者： LIU Dong-Mei YE Yong-Chun WANG Ding-Xiong Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

An analytical expression for the jet power extracted from the plunging region between a black hole （BH） horizon and the inner edge of the disk （hereafter the PL power） is derived based on an improved equivalent circuit in BH magnetosphere with a mapping relation between the radial coordinate of the plunging region and that of the remote astrophysical load. It is shown that the PL power is of great importance in explaining jet power and dominates over the BZ and DL powers for a wide value range of the BH spin. In addition, we show that the PL power derived in our model can be fitted with the strong jet powers of several 3CR FR I radio galaxies, which cannot be explained by virtue of the BZ mechanism. Furthermore, the condition for negative energy of the accreting particles in the plunging region is discussed with the validity of the second law of BH thermodynamics.

关键词： black hole accretion disk jet power radio galaxies

Observational appearances of hairy black holes in the framework of gravitational decoupling

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Communications in Theoretical Physics 2024年第8期76卷 103-117页

作者： Yizhi Liang Xin Lyu Jun Tao Center for Theoretical Physics College of PhysicsSichuan UniversityChengdu 610065China

We investigate the observational appearance of static and spherically symmetric hairy black holes in the framework of gravitational decoupling with the weak energy condition(WEC). Two types of thin illumination conditions are studied: spherical accretion and disk accretion. As the hairy parameter increases, the size of the photon sphere and photon rings in both models decreases, and the overall luminosity attenuation becomes more pronounced. In spherical accretion, the luminosity of infalling accretion is significantly lower than that of stationary accretion. In disk accretion the luminosity of the black hole is contributed by direct emission, the lensing ring and the photon ring. Employing four types of astrophysical disk luminosity model,we investigate the appearance of halos and note that their luminosities do not superimpose when the source is on or beyond the innermost stable circular orbit.

关键词： hairy black hole shadow gravitational decoupling accretion disk

Black hole images:A review

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Science China(Physics,Mechanics & Astronomy) 2023年第6期66卷 101-117页

作者： Songbai Chen Jiliang Jing Wei-Liang Qian Bin Wang Department of Physics Synergetic Innovation Centerfor Quantum Effects and ApplicationsHunan Normal UniversityChangsha 40081China Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China Escola de Engenharia de Lorena Universidade de Sao PauloSao Paulo 12602-810Brazil Faculdade de Engenharia de Guaratingueta Universidade Estadual PaulistaSao Paulo 12516-410Brazil School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China

In recent years,unprecedented progress has been achieved regarding black holes’observation through the electromagnetic *** images of the supermassive black holes M87*and Sgr A*released by the Event Horizon Telescope(EHT)Collaboration provided direct visual evidence for their existence,which has stimulated further studies on various aspects of the compact celestial ***,the information stored in these images provides a new way to understand the pertinent physical processes that occurred near the black holes,to test alternative theories of gravity,and to furnish insight into fundamental *** this review,we briefiy summarize the recent developments on the *** particular,we elaborate on the features and formation mechanism of black hole shadows,the properties of black hole images illuminated by the surrounding thin accretion disk,and the corresponding polarization *** potential applications of the relevant studies are also addressed.

关键词： black hole shadow accretion disk polarization image

A New Approach to Black hole Spin in X-Ray Binaries

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Chinese Physics Letters 2005年第10期22卷 2727-2730页

作者：左学勤汪定雄马任意 Department of Physics Huazhong University of Science and Technology Wuhan 430074

A new approach of detecting the black hole spin in x-ray binaries is proposed based on the model of the coexistence of the Blandford-Znajek （BZ） and magnetic coupling （MC） processes, in which the BZ process is used to power the jet emissions from x-ray binaries, and high frequency quasi-periodic oscillations （QPOs） are explained by a rotating hotspot in the inner region of the accretion disc surrounding a fast-spinning black hole. It is shown that the black hole spins of several x-ray binaries （XTE J1550-564, GRO d1665-40 and GRS 1915＋105） can be constrained in a rather narrow range, provided that QPOs and jets coexist in these sources.

关键词： QUASI-PERIODIC OSCILLATIONS accretion disk GRO J1655-40 RELATIVISTICJETS GALACTIC-CENTER GALAXY DISCOVERY XTE-J1550-564 EJECTION MODEL

Resonant behavior of stochastic oscillations of general relativistic disks driven by a memory-damped friction

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Chinese Physics B 2015年第5期24卷 682-686页

作者：汪志云陈培杰张良英 School of Physics and Electronic Engineering Hubei University of Arts and Science

By using a generalized Langevin equation to describe the vertieal oscillations of a general relativistic disk subjected to a memory-damped friction and a stochastic force, we derive the power spectrum density （PSD） of accretion disk oscillating luminosity by the method of Laplace transform, and discuss the influence of the system parameters on the resonant behavior in PSD curves. The results show that as the damping strength a and memory time τ of the friction increase, the variation of PSD with spectrum frequency f from monotonous decreasing to occurring maximums, and the phenomenon of a general stochastic resonance （SR） with a single peak and multi-peaks can be found in PSD curves. The radial distance parameter n, the mass M, and spin parameter a, of the black hole determine the inherent frequency of vertical oscillations in the disk, and they have significant influences on the SR phenomena in a system of black hole binaries.

关键词： accretion disk power spectrum density memory-damped friction stochastic resonance

Single planet formation regime in the high-ionization environment:Possible origin of hot Jupiters and super-Earths

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Geoscience Frontiers 2018年第4期9卷 1023-1031页

作者： Yusuke Imaeda Toshikazu Ebisuzaki RIKEN

We studied the particle growth in a protoplanetary disk in a high-ionization environment and found that icy planet formation is inactive for a disk with an ionization rate 100 times higher than that of the present Solar System. In particular, in the case of M 〈 10^（-7.4）M_☉yr^（-1）, only rocky planet formation occurs. In such a case, all the solid materials in the disk drift inward, eventually reach the inner MRI front,and accumulate there. They form a dense, thin sub-disk of solid particles, which undergoes gravitational instability to form rocky planetesimals. The planetesimals rapidly grow into a planet through pebble accretion. Consequently, rocky planets tend to be much larger than planets formed through other regimes（tandem planet formation regime and dispersed planet formation regime）, in which icy planet formation actively takes place. These rocky planets may evolve into hot Jupiters if they grow fast enough to the critical core mass of the runaway gas accretion before the dispersal of the disk gas, or they may evolve into super-Earths if the gas dispersed sufficiently early.

关键词： accretion disk Planet formation Magneto-rotational instability Galactic cosmic rays Hot Jupiter Super-Earth

Effects of dynamo magnetic fields on observational properties of accreting millisecond X-ray pulsars

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Research in Astronomy and Astrophysics 2021年第1期21卷 229-237页

作者： Dugasa Belay Zeleke Solomon Belay Tessema Seblu Humne Negu Ehtiopian Space Science and Technology Institute(ESSTI)Entoto Observatory and Research Center(EORC) Astronomy and Astrophysics Research and Development DepartmentP.O.Box 33679 Addis AbabaEthiopia

In this paper,we have investigated accreting millisecond X-ray pulsars,which are rapidly rotating neutron stars in low-mass X-ray *** systems exhibit coherent X-ray pulsations that arise when the accretion flow is magnetically channeled to the stellar ***,we have developed the fundamental equations for an accretion disk around accreting millisecond X-ray pulsars in the presence of a dynamo generated magnetic field in the inner part of the *** have also formulated the numerical method for the structure equations in the inner region of the disk and the highest accretion rate is enough to form the inner region of the disk,which is overpowered by radiation pressure and electron ***,we have examined our results with the effects of dynamo magnetic fields on accreting millisecond X-ray pulsars.

关键词： accretion disk neutron stars,pulsars millisecond X-ray pulsars

看见黑洞:“人类公布首张黑洞照片”事件解读

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科学通报 2019年第20期64卷 2077-2081页

作者：袁峰中国科学院上海天文台中国科学院大学

北京时间2019年4月10日21时,全球六个城市(美国华盛顿、比利时布鲁塞尔、智利圣地亚哥、中国上海、中国台北和日本东京)同时召开新闻发布会,公布了人类拍到的第一张黑洞照片.此次发布的黑洞图像揭示了室女座星系团中超大质量星系M87中... 详细信息

北京时间2019年4月10日21时,全球六个城市(美国华盛顿、比利时布鲁塞尔、智利圣地亚哥、中国上海、中国台北和日本东京)同时召开新闻发布会,公布了人类拍到的第一张黑洞照片.此次发布的黑洞图像揭示了室女座星系团中超大质量星系M87中心的黑洞.该黑洞距离地球5500万光年(1光年=9.4607×1015 m),质量为太阳的65亿倍.该照片不只是在天体物理学术界,甚至在整个社会上也引起了很大轰动.本文将介绍这张黑洞照片的来龙去脉.

关键词： black hole very-long-baseline interferometry accretion disk M87 general relativity magnetohydrodynamics

X-ray flares raising upon magnetar plateau as an implication of a surrounding disk of newborn magnetized neutron star

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Research in Astronomy and Astrophysics 2021年第12期21卷 326-336页

作者： Tian-Ci Zheng Long Li Le Zou Xiang-Gao Wang Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China

The X-ray flares have usually been ascribed to long-lasting activities of the central engine of gamma-ray bursts(GRBs),e.g.,fallback *** GRB X-ray plateaus,however,favor a millisecond magnetar central *** fallback accretion can be significantly suppressed due to the propeller effect of a ***,if the propeller regime cannot resist the mass flow onto the surface of the magnetar efficiently,the X-ray flares raising upon the magnetar plateau would be *** this work,such peculiar cases are connected to the accretion process of the magnetars,and an implication for magnetar-disc structure is *** investigate the repeated accretion process with multi-flare GRB 050730,and give a discussion for the accretion-induced variation of the magnetic field in GRB 111209 *** or more flares exhibit in the GRB 050730,060607 A and 140304 A;by adopting magnetar mass M=1.4 M_(⊙)and radius R=12 km,the average mass flow rates of the corresponding surrounding disk are 3.53×10^(-4)M_(⊙)s^(-1).4.23×10^(-4)M_(⊙)s^(-1),and 4.33×10^(-4)M_(⊙)s^(-1),and the corresponding average sizes of the magnetosphere are 5.01×10^(6)cm,6.45 x 10^(-6)cm,and 1.09×10^(-7)cm,respectively.A statistic analysis that contains eight GRBs within 12 flares shows that the total mass loading in single flare is~2×10^(-5)M_(⊙).In the lost mass of a disk,there are about 0.1%used to feed a collimated jet.

关键词： accretion accretion disk stars:magnetars gamma-ray burst:individual(GRB 050730,GRB 111209A)