共查询到20条相似文献，搜索用时 62 毫秒
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The effects of the Blandford–Znajek (BZ) process on the evolution of the central black holes of accretion discs are investigated by an analytical method and numerical calculations in this paper. It is shown that the BZ process reduces the rates of change of some parameters of the black hole, such as mass, angular momentum, dimensionless angular momentum and temperature, and the evolution of the central black hole towards the extreme Kerr black hole is depressed effectively. However, the rate of change of entropy of the central black hole is augmented in the BZ process. In addition, the consistency of the BZ process with the three laws of black hole thermodynamics is discussed. 相似文献
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A.F. Zakharov 《Astronomische Nachrichten》2002,323(6):538-541
We discuss basic ideas which were fundamental for the black hole concept. The major goal of the historical part is an attempt to explain the long way to the birth of the black hole concept, since the black hole solution was already found in 1916 by K. Schwarzschild, but the black hole concept was only introduced in 1967 by J.A. Wheeler. We discuss the basic notations of the black hole theory and observational manifestations of black holes. We analyse the possibility to interpret the very peculiar distortion of the Fe Kα‐line in such a way. 相似文献
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Andrea Cattaneo Martin G. Haehnelt Martin J. Rees 《Monthly notices of the Royal Astronomical Society》1999,308(1):77-81
The growth of supermassive black holes by merging and accretion in hierarchical models of galaxy formation is studied by means of Monte Carlo simulations. A tight linear relation between masses of black holes and masses of bulges arises if the mass accreted by supermassive black holes scales linearly with the mass-forming stars and if the redshift evolution of mass accretion tracks closely that of star formation. Differences in redshift evolution between black hole accretion and star formation introduce a considerable scatter in this relation. A non-linear relation between black hole accretion and star formation results in a non-linear relation between masses of remnant black holes and masses of bulges. The relation of black hole mass to bulge luminosity observed in nearby galaxies and its scatter are reproduced reasonably well by models in which black hole accretion and star formation are linearly related but do not track each other in redshift. This suggests that a common mechanism determines the efficiency for black hole accretion and the efficiency for star formation, especially for bright bulges. 相似文献
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The distribution of black hole spins in consideration of only the effect of merges is discussed. The angular momentum after merging is treated via the post-Newtonian approximation, and the effects of merges under different conditions are simulated by adopting the Monte Carlo method. The obtained results indicate that the major merge cannot make the distribution of black hole spins stable, but the minor merge can make the black hole spin smoothly slow down. The distribution of black hole spins can stay at a stable level with the overwhelming proportion of small spins, when the mass ratio of merging black holes takes the form of power-law function. In addition, based on the simulated results, the possible relationship between radio-loud active galactic nuclei (AGNs) and black hole spins is also discussed. Finally, the distribution of radio loudness is calculated and presented. 相似文献
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The problem of few black holes becomes important in multiple mergers of galaxies. If supermassive black holes in centres of galaxies are common, then interaction of three or four supermassive black holes should also be common. The merger of two galaxies with one black hole each produces a semi-stable black hole binary system. Subsequent mergers of galaxies with their own central black holes produces dynamical few-body evolution in which mergers of black holes occur. According to our numerical simulations this evolution typically ends when only one or two black holes remain and, in the latter case, they are ejected in opposite directions from the center of the galaxy. Even when we pick the initial black hole masses at random from a wide distribution, the two black hole ejections happen rather symmetrically. Sometimes the final masses differ considerably in which case only the lighter black hole is ejected. This is caused by the potential barrier of the galaxy itself which prevents the heavy slowly moving black hole flying out of the galaxy. We discuss OJ287 as a possible example of a multiple black hole system. 相似文献
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《Chinese Astronomy and Astrophysics》2007,31(2):109-116
The effect of variation of radiative efficiency on the growth of the black hole mass is discussed. In the process of accretion, the black hole's angular momentum varies, resulting in a variation of the radiative efficiency, and the growth of the black hole mass is thereby affected. For the exponential growth model of back holes and taking into account the effect of a varying radiative efficiency, the equation for the growth of the black hole mass is solved numerically. Compared to the model that assumes a constant radiative efficiency, the result indicates that variation of radiative efficiency has a marked, retarding effect on the growth of the black hole mass. This model can explain quantitatively some recent observational results. 相似文献
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T. X. Zhang 《Astrophysics and Space Science》2010,330(1):157-165
Modifying slightly the big bang theory, the author has recently developed a new cosmological model called black hole universe.
This new cosmological model is consistent with the Mach principle, Einsteinian general theory of relativity, and observations
of the universe. The origin, structure, evolution, and expansion of the black hole universe have been presented in the recent
sequence of American Astronomical Society (AAS) meetings and published recently in a scientific journal: Progress in Physics.
This paper explains the observed 2.725 K cosmic microwave background radiation of the black hole universe, which grew from
a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present
universe with hundred billion-trillions of solar masses. According to the black hole universe model, the observed cosmic microwave
background radiation can be explained as the black body radiation of the black hole universe, which can be considered as an
ideal black body. When a hot and dense star-like black hole accretes its ambient materials and merges with other black holes,
it expands and cools down. A governing equation that expresses the possible thermal history of the black hole universe is
derived from the Planck law of black body radiation and radiation energy conservation. The result obtained by solving the
governing equation indicates that the radiation temperature of the present universe can be ∼2.725 K if the universe originated
from a hot star-like black hole, and is therefore consistent with the observation of the cosmic microwave background radiation.
A smaller or younger black hole universe usually cools down faster. The characteristics of the original star-like or supermassive
black hole are not critical to the physical properties of the black hole universe at present, because matter and radiation
are mainly from the outside space, i.e., the mother universe. 相似文献
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By means of the semiclassical approximations for the action, the horizon of Kerr-Sen black hole is studied. The corrected entropy of the Kerr-Sen black hole in a low-energy string theory is calculated. By assumption of a flat Friedman-Robertson-Walker (F.R.W.) geometries, we study horizon and present the semi-classic approximation affects of the thermodynamics properties. We discuss some physical consequences of this result and the properties of the Kerr-Sen black hole. 相似文献
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De Sitter背景时空中NUT-Kerr-Newman黑洞的玻色子熵 总被引：1，自引：0，他引：1
众所周知，一般黑洞的欧拉示性数都为2(或者为0)，而NUT—Kerr—Newman黑洞是个例外，其欧拉示性数大于2.因此计算NUT—Kerr—Newman黑洞的玻色子熵有特殊的意义．运用在brick-wall方法的基础上发展起来的膜模型计算了NUT-Kerr—Newman黑洞在de Sitter时空背景下的玻色子熵．结果表明，在选取适当的截断因子的情况下，该黑洞的熵仍满足Bekenstein—Hawking面积定律． 相似文献
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Sun Yu-Tao Liu Jie-Ying Liu Jin-zhong Ai Yan-Li Zhou Ming Qiao Er-lin 《Chinese Astronomy and Astrophysics》2011,35(2):103
The research on quasar OJ 287 has lasted over 100 years. OJ 287 exhibits the phenomenon of periodic two-peak outbursts with the eruptive period of 12 years. Observations are rather well interpreted with the black hole binary model. In this model, the secondary black hole moves around the primary black hole and crashes against the accretion disk of the primary black hole, causing outbursts. This model reasonably explains the light curves of OJ 287 and correctly predicts the time of future outbursts. These indirectly justify the precessional effect of general relativity and the existence of gravitational waves. The massive black hole in the center of galaxy is an important kind of gravitational wave source. However, the number of the galaxies with precisely determined kinematical equations of inner components is quite small. The precise kinematic orbits of black holes are provided by the black hole binary model, so the radiation of gravitational waves can be studied on the basis of these kinematic orbits. Based on the existing work, the evolutionary relations of the radiation power and waveform of gravitational waves with time are first derived by using the post-Newtonian approximation method. According to the current progress of the detection equipment of gravitational waves, i.e., IPTA (International Pulsar Timing Array), the direct detection of gravitational waves from OJ 287 may be possible within the future decade. 相似文献
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We have obtained a solution of the Dirac equation near the horizon of a Kerr-Newman black hole and compared it with the solution of the Klein-Gordon equation. We first generalized the work of LIU Liao and XU Dian-yan for a quasi-extreme Kerr black hole to a quasi-extreme Kerr-Newman black hole, then further generalized to a general Kerr-Newman black hole, and thereby verified that the Dirac particles emitted by a general Kerr-Newman black hole do have a black-body energy spectrum. 相似文献
14.
On the formation and evolution of black hole binaries 总被引：1，自引：0，他引：1
Ph. Podsiadlowski S. Rappaport Z. Han 《Monthly notices of the Royal Astronomical Society》2003,341(2):385-404
We present the results of a systematic study of the formation and evolution of binaries containing black holes and normal-star companions with a wide range of masses. We first reexamine the standard formation scenario for close black hole binaries, where the progenitor system, a binary with at least one massive component, experienced a common-envelope phase and where the spiral-in of the companion in the envelope of the massive star caused the ejection of the envelope. We estimate the formation rates for different companion masses and different assumptions about the common-envelope structure and other model parameters. We find that black hole binaries with intermediate- and high-mass secondaries can form for a wide range of assumptions, while black hole binaries with low-mass secondaries can only form with apparently unrealistic assumptions (in agreement with previous studies).
We then present detailed binary evolution sequences for black hole binaries with secondaries of 2 to 17 M⊙ and demonstrate that in these systems the black hole can accrete appreciably even if accretion is Eddington-limited (up to 7 M⊙ for an initial black hole mass of 10 M⊙ ) and that the black holes can be spun up significantly in the process. We discuss the implications of these calculations for well-studied black hole binaries (in particular GRS 1915+105) and ultraluminous X-ray sources of which GRS 1915+105 appears to represent a typical Galactic counterpart. We also present a detailed evolutionary model for Cygnus X-1, a massive black hole binary, which suggests that at present the system is most likely in a wind mass-transfer phase following an earlier Roche-lobe overflow phase. Finally, we discuss how some of the assumptions in the standard model could be relaxed to allow the formation of low-mass, short-period black hole binaries, which appear to be very abundant in nature. 相似文献
We then present detailed binary evolution sequences for black hole binaries with secondaries of 2 to 17 M
15.
汪定雄 《中国天文和天体物理学报》1996,(1)
本文利用李立新和刘辽导出的黑洞视界附近的辐射态方程，计算了约束在一个球形盒子中的目引力辐射体系的墙（不含中心黑洞和含有中心黑洞两种情况）．与Sorkin等人的计算比较，本文的结果不会出现发散困难，而且体系的总摘（包括中心黑洞的墙）的上阳正好等于坍缩后形成的同质量的黑洞嫡．作者认为，自引力辐射体系坍绩的合理模式是先形成中心黑洞，然后中心黑洞逐渐长大直至整个体系全部坍缩为黑洞．在坍缩过程中，任一中间态的媳总是比末态的黑洞墙小，到坍缩过程结束总熵才等于对应的黑洞摘．这一结果为黑洞滴的起源提供了一个合理的解释． 相似文献
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R. J. McLure M. J. Jarvis T. A. Targett J. S. Dunlop P. N. Best 《Monthly notices of the Royal Astronomical Society》2006,368(3):1395-1403
We present the results of a study which uses the 3C RR sample of radio-loud active galactic nuclei to investigate the evolution of the black hole:spheroid mass ratio in the most massive early-type galaxies from 0 < z < 2 . Radio-loud unification is exploited to obtain virial (linewidth) black hole mass estimates from the 3C RR quasars, and stellar mass estimates from the 3C RR radio galaxies, thereby providing black hole and stellar mass estimates for a single population of early-type galaxies. At low redshift ( z ≲ 1) , the 3C RR sample is consistent with a black hole:spheroid mass ratio of M bh / M sph ≃ 0.002 , in good agreement with that observed locally for quiescent galaxies of similar stellar mass ( M sph ≃ 5 × 1011 M⊙ ) . However, over the redshift interval 0 < z < 2 the 3C RR black hole:spheroid mass ratio is found to evolve as M bh / M sph ∝ (1 + z )2.07±0.76 , reaching M bh / M sph ≃ 0.008 by redshift z ≃ 2 . This evolution is found to be inconsistent with the local black hole:spheroid mass ratio remaining constant at a moderately significant level (98 per cent). If confirmed, the detection of evolution in the 3C RR black hole:spheroid mass ratio further strengthens the evidence that, at least for massive early-type galaxies, the growth of the central supermassive black hole may be completed before that of the host spheroid. 相似文献
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Yu-Ying Bao Xiong Zhang Luo-En Chen Hao-Jing Zhang Zhao-Yang Peng Yong-Gang Zheng 《Chinese Astronomy and Astrophysics》2008
The redshift, central black hole mass and accretion rate are important parameters when studying the AGN evolution. The central black hole masses for 172 quasars and Seyfert galaxies are calculated in this paper using the reverberation mapping method. The distributions of central black hole masses, redshifts and the Eddington accretion rates are analyzed, to verify the transition from the quasar to the Seyfert galaxy in the course of evolution. 相似文献
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De-Jiang Qi 《Astrophysics and Space Science》2014,349(1):33-37
In this paper, the expression of the adiabatic invariant quantity is presented in the dragged–Painlevé coordinate system. Via revisited adiabatic invariant quantity, using Bohr–Sommerfeld quantization rule and the first law of the black hole thermodynamics, we derive the spectroscopy of the black hole. The result shows that the area and entropy spectra are respectively equally spaced and independent of black hole parameters and the area spectrum of the black hole is $\Delta A=8\pi l_{P}^{2}$ , which confirms the initial proposal of Bekenstein, and there is no need to impose the small angular momentum limit in contrast to the quasinormal mode method. 相似文献
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A. Farmany H. Noorizadeh R. Sahraei M. H. Majlesara S. A. A. Trohid 《Astrophysics and Space Science》2012,339(2):323-327
In the present paper, based on the generalized uncertainty principle, the Parikh-Wilczek black hole tunneling radiation is
studied. It is shown that the black hole tunneling radiation receives a correction. Furthermore a bound on the tunneling approach,
is shown to be valid when, based on the holographic principle, a bound applied to the black hole entropy. 相似文献
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Shude Mao Hans J. Witt Leon V. E. Koopmans 《Monthly notices of the Royal Astronomical Society》2001,323(2):301-307
Recent observations indicate that many if not all galaxies host massive central black holes. In this paper we explore the influence of black holes on the lensing properties. We model the lens as an isothermal ellipsoid with a finite core radius plus a central black hole. We show that the presence of the black hole substantially changes the critical curves and caustics. If the black hole mass is above a critical value, then it will completely suppress the central images for all source positions. Realistic central black holes are likely to have masses below this critical value. Even in such subcritical cases, the black hole can suppress the central image when the source is inside a zone of influence, which depends on the core radius and black hole mass. In the subcritical cases, an additional image may be created by the black hole in some regions, which for some radio lenses may be detectable with high-resolution and large dynamic range VLBI maps. The presence of central black holes should also be taken into account when one constrains the core radius from the lack of central images in gravitational lenses. 相似文献