Top Research Papers on Black Holes

What is the nature of the energy spectrum of a black hole ? The algebraic approach to black hole quantization requires the horizon area eigenvalues to be equally spaced. As stressed long ago by by Mukhanov, such eigenvalues must be exponentially degenerate with respect to the area quantum number if one is to understand black hole entropy as reflecting degeneracy of the observable states. Here we construct the black hole states by means of a pair of "creation operators" subject to a particular simple algebra, a slight generalization of that for the harmonic oscillator. We then prove rigorously ...

Brandon Carter’s lectures on the general theory of stationary black holes, reprinted here as a Golden Oldie, belong to the vivid legend of the 1972 Les Houches Summer School.1 The School was a marvelous and unforgettable experience for its youngest student participants, like me. Although Carter and a few other lecturers were just slightly older than most of us, they already enjoyed the fame of deep thinkers, great physicists and masterly mathematicians, and were well-known for their fundamental discoveries in the black hole theory. Carter’s black hole lectures at Les Houches concentrated aroun...

The model is constructed, some features of which comes from quantum thin dust shells and is, in fact, an extension of the "no hair" property of classical black hole on a quantum level. It appears that the proposed classical analog of quantum black hole is heated, the temperature being exactly the Hawking's temperature.

The first picture of block hole was released on April 10th, 2019. This breakthrough came after a decade of collaborate work to align the myriad parts of the giant project and gain the highest resolution possible from the Earth’s surface. Even from our original consideration, block hole is a mysterious greedy hole that can suck anything away no matter how big the matter is. However, the newly released results indicated that block hole is not the imaginary hole; it is as a dark shadow within a doughnut-like ring of hot, glowing material with almost the size of our solar system.

Supposedly, matter falls inside the black hole whenever it reaches its event horizon. The Planck scale, however, imposes a limit on how much matter can occupy the center of a black hole. It is shown here that the density of matter exceeds Planck density in the singularity, and as a result, spacetime tears apart. After the black hole is formed, matter flows from its center to its border due to a topological force; namely, the increase on the tear of spacetime due to its limit, until it reaches back to the event horizon, generating the firewall phenomenon. We conclude that there is no spacetime ...

Presented evidence, that Black Hole is hole. Namely right behind the black surface (event horizon for non-rotational BH) there are no space nor time. No spacetime. Just as it would be prior to the Big Bang. First composite image of Black Hole from Event Horizon Telescope is another evidence for that, with the resulting correction of the reported mass.

It is shown in this paper that there is a difficulty in conventional black hole thermodynamics. To overcome the difficulty we introduce a "surface" near the event horizon as an additional thermodynamical object. The mass and entropy of the additional "surface" are the same as the correction of mass of Schwarzschild black hole obtained in the back-reaction program up to a constant factor. This implies that some effects of back reaction are automatically considered in our thermodynamic phenomenological treatment.

Acoustic black holes are very interesting non-gravitational objects which can be described by the geometrical formalism of General Relativity. These models can be useful to experimentally test effects otherwise undetectable, as for example the Hawking radiation. The back-reaction effects on the background quantities induced by the analogue Hawking radiation could be the key to indirectly observe it. We briefly show how this analogy works and derive the backreaction equations for the linearized quantum fluctuations in the background of an acoustic black hole. A first order in ℏ solution is give...

It is shown in this paper that there is a difficulty in conventional black hole thermodynamics. To overcome the difficulty we introduce a "surface" near the event horizon as an additional thermodynamical object. The mass and entropy of the additional "surface" are the same as the correction of mass of Schwarzschild black hole obtained in the back-reaction program up to a constant factor. This implies that some effects of back reaction are automatically considered in our thermodynamic phenomenological treatment.

We investigate the relations between the black hole shadow and black hole thermodynamics. We first show that phase structures of the black holes can be characterized by the shadow radii of the black holes. Then according to the second law of the black hole thermodynamics, we propose that the shadow radius of the black hole does not decrease with time. Lastly, the minimal sizes of the black hole shadows are given considering the third law of the black hole thermodynamics.

We present a simple analytical model for studying the collapse of an ultracompact stellar object (regular black hole mimicker with infinite redshift surface) to form a (integrable) black hole, in the framework of General Relativity. Both initial and final configurations have the same ADM mass, so that the transition represents an internal redistribution of matter without emission of energy. The model, despite being quite idealized, can be viewed as a good starting point to investigate near-horizon quantum physics

An approach based on considerations of the nonclassical energy momentum tensor outside the event horizon of a black hole provides additional physical insight into the nature of discrete quantum hair on black holes and its effect on black hole temperature.

Black holes are a continuing source of mystery. Although their classical properties have been understood since the 1970's, their quantum properties raise some of the deepest questions in theoretical physics. Some of these questions have recently been answered using string theory. I will review these fundamental questions, and the aspects of string theory needed to answer them. I will then explain the recent developments and new insights into black holes that they provide. Some remaining puzzles are mentioned in the conclusion.

Supermassive black holes are nowadays believed to reside in most local galaxies. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I'll discuss black hole formation processes that are likely to place at early cosmic epochs, and how massive black hole evolve in a hierarchical Universe. The mass of the black holes that we detect today in nearby galaxy has mostly been accumulated by accr...

We extend the previous work on 3D black hole excision to the case of distorted black holes, with a variety of dynamic gauge conditions that respond naturally to the spacetime dynamics. We show that in evolutions of highly distorted, rotating black holes, the combination of excision and the gauge conditions we use is able to drive the coordinates to a frame in which the system looks almost static at late times. Further, we show for the first time that one can extract accurate wave forms from these simulations, with the full machinery of excision and dynamic gauge conditions. The evolutions can ...

The black hole is the invisible celestial body in the universe.This paper sketches the forming and property of the black hole.Black hole,absolutely can't explain the affairs in this world.

In General Relativity, the spacetimes of black holes have three fundamental properties: (i) they are the same, to lowest order in spin, as the metrics of stellar objects; (ii) they are independent of mass, when expressed in geometric units; and (iii) they are described by the Kerr metric. In this paper, we quantify the upper bounds on potential black-hole metric deviations imposed by observations of black-hole shadows and of binary black-hole inspirals in order to explore the current experimental limits on possible violations of the last two predictions. We find that both types of experiments ...

Can we determine spin parameters of black holes by observations of black hole shadows in accretion disks? In order to answer this question, we have investigated shapes and positions of black hole shadows in optically thick accretion disks around Kerr black holes. In conclusion, in order to measure black hole spin parameters from shapes and positions of black hole shadows, it is crucially important to determine a position of a mass centers of a black hole in a region of a black hole shadow.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A Schwarzschild Black Hole (BH) is the gravitational field due to a neutral point mass, and it turns out that the gravitational mass of a neutral point mass: $M=0$ (Arnowitt, Deser, Misner, PRL 4, 375, 1960). The same result is also suggested by Janis, Newman, and Winicour (PRL 20, 878, 1968). In 1969, Bel gave an explicit proof that for a Schwarzschild BH, $M=0$ (Bel, JMP 10, 1051, 1969). The same result follows from the fact the timelike geodesic of a test particle would turn null if it would ever arrive at an event horizon (Mitra, FPL, 2000, 2002). Non-occurrrence of trapped surfaces in con...

A brief overview of the methods commonly used to determine or estimate the black hole mass in quiescent or active galaxies is presented and it is argued that the use of mass-scaling relations is both a reliable and the preferred method to apply to large samples of distant quasars. The method uses spectroscopic measurements of a broad emission-line width and continuum luminosity and currently has a statistical 1 sigma uncertainty in the absolute mass values of about a factor of 4. Potentially, this accuracy can be improved in the future. When applied to large samples of distant quasars it is ev...

The entropy formula of the black hole is proposed, which is constructed by the intersecting D1-brane and D5-branes with no momentum, whose compactification radii are constrained by the surface gravities in ten-dimensions.

The first chapter gives a brief introduction to the subject of blackhole thermodynamics and highlights the motivation behind our work. The second chapter basically provides a brief review of the general theory of relativity and goes on to discuss the different types of "standard" blackholes. The third chapter gives a review of the four laws of thermodynamics and discusses the corresponding laws of blackhole mechanics and their analogy with the thermodynamic laws. It also provides an introduction to the Generalised second law and shows how it resolved the glaring aws in the thermodynam...

We propose a method for measuring the black hole charge by imaging a black hole shadow in a galactic center by future interferometers. Even when the black hole is uncharged, it is possible to confirm the charge neutrality by this method. We first derive the analytic formulae of the black hole shadow in an optically thin medium around a charged spinning black hole, and then investigate how contours of the black hole shadow depend on the spin and the charge of the black hole for several inclination angles between the rotation axis of the black hole and the observer. This method only assumes stat...

We present a model for high-energy emission sources generated by a standing magnetohydrodynamical (MHD) shock in a black hole magnetosphere. The black hole magnetosphere would be constructed around a black hole with an accretion disk, where a global magnetic field could be originated by currents in the accretion disk and its corona. Such a black hole magnetosphere may be considered as a model for the central engine of active galactic nuclei, some compact X-ray sources, and gamma-ray bursts. The energy sources of the emission from the magnetosphere are the gravitational and electromagnetic ener...

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The presence of supermassive black holes (SMBHs, $M_{\bullet}\sim 10^{6-10}~M_{\odot}$) in the first cosmic Gyr ($z\gtrsim 6$) challenges current models of BH formation and evolution. We propose a novel mechanism for the formation of early SMBH seeds based on primordial black holes (PBHs). We assume a non-Gaussian primordial power spectrum as expected in inflationary models; these scenarios predict that PBHs are initially clustered and preferentially formed in the high-$\sigma$ fluctuations of the large-scale density field, out of which dark matter (DM) halos are originated. Our model accounts...

In this paper we study the qualitative features induces by corrections to GR coming from String Theory, on the shadows of rotating black holes. We deal with the slowly rotating black hole solutions up to order $\mathcal{O}(a^3)$, to first order in $\alpha'$, including also the dilaton. We provide a detailed characterization of the geometry, as well as the innermost stable circular orbit (ISCO) and photon ring, and then we proceed to obtain the black hole images within the relativistic thin-disk model. We characterize the images by computing the diameter, displacement and asymmetry. A compariso...

We present a new class of quantum two dimensional dilaton gravity model, which is described by $SL(2,R)/U(1)$ gauged Wess-Zumino-Witten model deformed by $(1,1)$-operator. We analyze the model by ${1 \over k}$ expansion ($k$ is the level of $SL(2,R)$ Wess-Zumino-Witten model) and we find that the curvature singularity does not appear when $k$ is large and the Bondi mass is bounded from below. Furthermore, the rate of the Hawking radiation in the quantum black hole created by shock wave goes to zero asymptotically and the radiation stops when the Bondi mass vanishes.

The possible formation mechanisms of massive close binary black holes (BHs) that can merge in the Hubble time to produce powerful gravitational wave bursts detected during advanced LIGO O1 and O2 science runs include the evolution from field low-metallicity massive binaries, the dynamical formation in dense stellar clusters and primordial BHs. Different formation channels produce different source distributions of total masses ${M_\mathrm{tot}}$ and effective spins $\chi_\mathrm{eff}$ of coalescing binary BHs. Using a modified \textsc{bse} code, we carry out extensive population synthesis calcu...

In this paper, we present the spherically symmetric Proca star in the presence of a phantom field and obtain a traversable wormhole solution for non-trivial topological spacetime. Using numerical methods, symmetric solutions and asymmetric solutions are obtained in two asymptotically flat regions. We find that when changing the throat size $r_{0}$, both the mass $M$ and the Noether charge $Q$ no longer have the spiral characteristics of an independent Proca star, furthermore, the asymmetric solution can be turned into the symmetric solution at some frequency $\omega$ in certain $r_{0}$. In par...

While the standard point of view is that the ultimate endpoint of black hole evolution is determined by Hawking evaporation, there is a growing evidence that classical and semi-classical instabilities affect both black holes with inner horizons as well as their ultra-compact counterparts. In this essay we start from this evidence pointing towards extremal black holes as stable endpoints of the gravitational collapse, and develop a general class of spherical and axisymmetric solutions with multiple extremal horizons. Excluding more exotic possibilities, entailing regular cores supporting wormho...

As an example of a black hole in a non-flat background a composite static spacetime is constructed. It comprises a vacuum Schwarzschild spacetime for the interior of the black hole across whose horizon it is matched on to the spacetime of Vaidya. The scale length of the exterior sets a maximum to the black hole mass. To obtain a non-singular exterior, the Vaidya metric is matched to an Einstein universe. The behaviour of scalar waves is studied in this composite model.

The dynamics of galactic nuclei reflects the presence of supermassive black holes (SBHs) in many ways. Single SBHs act as sinks, destroying a mass in stars equal to their own mass in roughly one relaxation time and forcing nuclei to expand. Formation of binary SBHs displaces a mass in stars roughly equal to the binary mass, creating low-density cores and ejecting hyper-velocity stars. Gravitational radiation recoil can eject coalescing binary SBHs from nuclei, resulting in offset SBHs and lopsided cores. We review recent work on these mechanisms and discuss the observable consequences.

A black hole is a region in space-time. It’s a region from where nothing can escape not even time. Some physicist believes that this is due to the strong gravitational force exhibited by the black hole. It can also be observed that not even electromagnetic radiation such as light can’t escape from black hole. But I have a different view at this behavior of black hole and will also explain about the existence of more than one cosmos in this paper. Cosmos is very beautiful if we perform thought experiment, look inside it and concentrate we can observe things that can answer lots of our questions...

Physicists have theories about white holes: cosmic monsters that overlap the line between tall tale and actuality. Yet to be seen in the space, white holes might be only mathematical giants. But according to recent research, if a speculative theory known as loop quantum gravity is true, white holes could be not just only real but we might have already observed them. A white whole is, somewhat, the reverse of a black hole. [10] That’s what some physicists have argued for years: That black holes are the ultimate vaults, entities that suck in information and then evaporate without leaving behind ...

2 The Schwarzschild solution 8 2.1 Gravitational redshift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Geodesics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3 Eddington-Finkelstein coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4 Finklestein diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.5 Gravitational collapse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.6 Black hole region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

Who says you can't get anything out of a black hole? In the past two years, astronomers have taken unprecedented aim at the first black hole ever found, Cygnus X-1. Using a vast armada of instruments, they have pinpointed Cygnus X-1's distance, which has let them measure the black hole's mass and even determine how fast it spins. These feats have then motivated two other astronomical teams to decipher the black hole's past and forecast its future. The flurry of recent activity concerning an object astronomers discovered nearly half a century ago has one simple cause: for the first time, we kno...

SU(3) Einstein-Yang-Mills-dilaton theory possesses sequences of static spherically symmetric sphaleron and black hole solutions for the SU(2) and the SO(3) embedding. The solutions depend on the dilaton coupling constant γ, approaching the corresponding Einstein-Yang-Mills solutions for γ → 0, and Yang-Millsdilaton solutions in flat space for γ → ∞. The sequences of solutions tend to Einstein-Maxwell-dilaton solutions with different magnetic charges. The solutions satisfy analogous relations between the dilaton field and the metric for general γ. Thermodynamic properties of the black hole solu...

Black holes are among the most intriguing objects in modern physics. Their influence ranges from powering quasars and other active galactic nuclei, to providing key insights into quantum gravity. We review the observational evidence for black holes, and briefly discuss some of their properties. We also describe some recent developments involving cosmic censorship and the statistical origin of black hole entropy.

The unlucky star that wanders too close to a supermassive black hole faces a catastrophic end. Initially, it bulges slightly due to tidal forces, just as Earth’s oceans bulge in response to the Moon’s gravity. Over the next half-hour or so, increasing gravitational stress rips the star apart. Stellar remains spread in a wide spiral; the gas that isn’t ejected at high speeds circles back to feed the black hole, glowing brighthot before it disappears into its gaping maw. Astronomers first proposed that stars could become victim to tidal shredding by black holes in 1975, but it took two decades f...

Black holes seem like something out of science fiction, but they are real. Now that we understand the relevant properties of gravity we can separate fact from fiction. We start by defining black holes and showing how they differ fromthe simple Newtonian idea of “no escape.” Time and space seem to swap meaning inside the black hole, so that “forward in time” is a direction that points toward the center of the black hole. We then look at the astrophysical evidence that black holes really exists: how we can observe them, as well as the limits to our observations.We then examine facts andmyths abo...

Chapter 3 used the Schwarzschild metric to obtain predictions for the Solar System. In this chapter, that metric is derived as the unique static, spherically symmetric solution of the vacuum Einstein field equations. For the Solar System, this vacuum solution must be joined to an “interior solution” describing the interior of the Sun. Such solutions are discussed briefly. If, on the other hand, one assumes “vacuum all the way down,” the solution describes a black hole. The chapter analyzes the geometry and physics of the nonrotating black hole: the event horizon, the Kruskal-Szekeres extension...

They are out there in the sky in huge numbers. They are the most astonishing objects in the universe. Their existence was predicted and understood before we detected them. They behave precisely as the theory predicted. Yet, we do not know what happens at their center, nor in their future. But this confusion is our key towards what we most lack in fundamental physics: understanding quantum gravity.

The choice is between a humane caring for the chronically ill and disabled on the one hand and public-health interventions on the other, and the voracious competitor to them both is high-cost technology, centered on the doctor-hospital complex.

The following is a cue rundown descriptive analysis of John Barry's score to Walt Disney's The Black Hole. When I studied the score at Disney Studio in the spring of 1990, I did not have time to focus on each and every cue. In fact, my primary focus was on several favorite cues. I felt irresistibly drawn towards The Black Hole! This applies to the musical score, not so much to the movie itself that is an odd mixture of science fiction and Disney! When you see those Disney-cartoonish robots "Vincent" (voiced by Roddy McDowell) and "Bob" (voiced by Slim Pickens), you'll know what I mean. Anthony...

Abstract This reading of Charles Burns’s graphic novel Black Hole, and of its four principle characters, Keith, Chris, Rob and Eliza, relies heavily upon ideas drawn from Lacanian psychoanalysis: fantasy and symptom, desire and object a, Symbolic and Real as well as the notion of subjective destitution. Freud’s understanding of melancholy will aid the last of those discussions. Rumination on the book’s title and the mysterious infection, the “bug,” which drives the narrative, finds a suggestive analogy in relation to the theme of abjection so abundantly pictured in the text. Building upon the ...

The observational evidence for black holes is reviewed, some recent developments involving cosmic censorship and the statistical origin of black hole entropy are described, and some of their properties are described.

The metric of Gibbons-Maeda black hole in the presence of a cosmological constant is constructed and verified. The dilaton potential with respect to the cosmological constant is obtained. It is found that the cosmological constant is coupled to the dilaton field. PACS number(s): 04.20.Ha, 04.50.+h, 04.70.Bw Typeset using REVTEX E-mail: gaocj@mail.tsinghua.edu.cn E-mail: zhangsn@mail.tsinghua.edu.cn 1

In the second part of the book, I argue that the four biggest mysteries of modern physics and astronomy—dark matter, dark energy, black holes, and the Big Bang—sink their roots into the physics of the infinitely small. And I argue that gravitational waves may shed new light on, and possibly solve, each of these four mysteries. I start here by introducing the problem of dark matter, the mysterious substance that permeates the Universe at all scales and describe the gravitational waves observations that might soon elucidate its nature. The next time you see the Sun shining in the sky, consider t...

In 2015, a huge scientific collaboration called LIGO discovered gravitational waves. Gravitational waves are huge ripples in spacetime that occur as a result of astrophysical events, like collisions between massive things in outer space. In 2015, the LIGO scientists found a signal that came from two black holes merging. This was huge scientific news, and resulted in the 2017 Nobel Prize in Physics for Rai Weiss, Kip Thorne, and Barry Barish.