scholarly journals Decline of the Current Quadrupole Moment during the Merger Phase of Binary Black Hole Coalescence

Universe ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 3
Author(s):  
Fan Zhang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Quadrupole Moment ◽  
Total Angular Momentum ◽  
Quasinormal Modes ◽  
Binary Black Hole ◽  
Mass Quadrupole

Utilizing the tools of tendex and vortex, we study the highly dynamic plunge and merger phases of several π -symmetric binary black hole coalescences. In particular, we observe a decline of the strength of the current quadrupole moment compared to that of the mass quadrupole moment during the merger phase, contrary to a naive estimate according to the dependence of these moments on the separation between the black holes. We further show that this decline of the current quadrupole moment is achieved through the remnants of the two individual spins becoming nearly aligned or anti-aligned with the total angular momentum. We also speculate on the ability to achieve a consistency between the electric and magnetic parity quasinormal modes.

scholarly journals Greybody factor and quasinormal modes of Regular Black Holes

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Ángel Rincón ◽  
Victor Santos
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Classical Solution ◽  
Quantum Number ◽  
Quasinormal Modes ◽  
Wkb Method ◽  
Regular Black Hole ◽  
Gravitational Perturbations ◽  
Black Hole Solutions

AbstractIn this work, we investigate the quasinormal frequencies of a class of regular black hole solutions which generalize Bardeen and Hayward spacetimes. In particular, we analyze scalar, vector and gravitational perturbations of the black hole with the semianalytic WKB method. We analyze in detail the behaviour of the spectrum depending on the parameter p/q of the black hole, the quantum number of angular momentum and the s number. In addition, we compare our results with the classical solution valid for $$p = q = 1$$ p = q = 1 .

scholarly journals QUASINORMAL MODES AND LATE-TIME TAILS OF CANONICAL ACOUSTIC BLACK HOLES

2007 ◽  
Vol 16 (07) ◽  
pp. 1211-1218 ◽  
Author(s):  
PING XI ◽  
XIN-ZHOU LI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Wave Propagation ◽  
Angular Momentum ◽  
Numerical Method ◽  
Time Scale ◽  
Quasinormal Modes ◽  
Late Time ◽  
Classical Wave ◽  
Acoustic Black Holes

In this paper, we investigate the evolution of classical wave propagation in the canonical acoustic black hole by a numerical method and discuss the details of the tail phenomenon. The oscillating frequency and damping time scale both increase with the angular momentum l. For lower l, numerical results show the lowest WKB approximation gives the most reliable result. We also find that the time scale of the interim region from ringing to tail is not affected obviously by changing l.

scholarly journals Coalescence of Kerr Black Holes—Binary Systems from GW150914 to GW170814

Entropy ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 1017
Author(s):  
Bogeun Gwak
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Gravitational Wave ◽  
Orbital Angular Momentum ◽  
Binary Systems ◽  
Analytical Form ◽  
Angular Momenta ◽  
Binary Black Hole ◽  
Kerr Black Holes

We investigate the energy of the gravitational wave from a binary black hole merger by the coalescence of two Kerr black holes with an orbital angular momentum. The coalescence is constructed to be consistent with particle absorption in the limit in which the primary black hole is sufficiently large compared with the secondary black hole. In this limit, we analytically obtain an effective gravitational spin–orbit interaction dependent on the alignments of the angular momenta. Then, binary systems with various parameters including equal masses are numerically analyzed. According to the numerical analysis, the energy of the gravitational wave still depends on the effective interactions, as expected from the analytical form. In particular, we ensure that the final black hole obtains a large portion of its spin angular momentum from the orbital angular momentum of the initial binary black hole. To estimate the angular momentum released by the gravitational wave in the actual binary black hole, we apply our results to observations at the Laser Interferometer Gravitational-Wave Observatory: GW150914, GW151226, GW170104, GW170608 and GW170814.

scholarly journals Gravitational and electromagnetic radiation from binary black holes with electric and magnetic charges: elliptical orbits on a cone

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Lang Liu ◽  
Øyvind Christiansen ◽  
Wen-Hong Ruan ◽  
Zong-Kuan Guo ◽  
Rong-Gen Cai ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Gravitational Waves ◽  
Emission Rates ◽  
Total Emission ◽  
Binary Black Holes ◽  
Binary Black Hole ◽  
Elliptical Orbits ◽  
Electromagnetic Radiations

AbstractExtending the electromagnetic and gravitational radiations from binary black holes with electric and magnetic charges in circular orbits in Liu et al. (Phys. Rev. D 102:103520, 2020), we calculate the total emission rates of energy and angular momentum due to gravitational and electromagnetic radiations from dyonic binary black holes in precessing elliptical orbits. It is shown that the emission rates of energy and angular momentum due to gravitational and electromagnetic radiations have the same dependence on the conic angle for different orbits. Moreover, we obtain the evolutions of orbits and find that a circular orbit remains circular while an elliptic orbit becomes quasi-circular due to electromagnetic and gravitational radiations. Using the evolution of orbits, we derive the waveform models for dyonic binary black hole inspirals and show the amplitudes of the gravitational waves for dyonic binary black hole inspirals differ from those for Schwarzschild binary black hole inspirals, which can be used to test electric and magnetic charges of black holes.

SPIN EXPANSION FOR HEAD-ON COLLISION OF TWO BLACK HOLES

2011 ◽  
Vol 20 (01) ◽  
pp. 43-57 ◽  
Author(s):  
ZHOUJIAN CAO ◽  
CHENZHOU LIU
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
New Method ◽  
Initial State ◽  
Final State ◽  
The Third ◽  
Binary Black Hole ◽  
Expansion Technique

The spin expansion technique proposed in [L. Boyel, M. Kesden and S. Nissanke, Phys. Rev. Lett.100 (2008) 151101] is very powerful to analyze the relation between the initial state of binary black hole and the final state of the merged black hole. But this technique needs orbital angular momentum to determine the third direction of a triad. Without this triad we cannot get the decomposed components of the involved quantities, and the spin expansion breaks down. The head-on collision of two black holes, whose orbital angular momentum vanishes, falls into this case. In this paper we propose a new method to construct a triad for spin expansion technique. With this new method, we get the same set of equations as in the above-mentioned paper. Furthermore, we use numerical simulations to illustrate the validity of our new method for the head-on collision of two black holes.

scholarly journals Gaseous Disks in the Nuclei of Elliptical Galaxies

1997 ◽  
Vol 163 ◽  
pp. 620-625 ◽  
Author(s):  
H. Ford ◽  
Z. Tsvetanov ◽  
L. Ferrarese ◽  
G. Kriss ◽  
W. Jaffe ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Accretion Disks ◽  
Large Scale ◽  
Elliptical Galaxies ◽  
Central Mass ◽  
Massive Black Holes ◽  
Radio Jets

AbstractHST images have led to the discovery that small (r ~ 1″ r ~ 100 – 200 pc), well-defined, gaseous disks are common in the nuclei of elliptical galaxies. Measurements of rotational velocities in the disks provide a means to measure the central mass and search for massive black holes in the parent galaxies. The minor axes of these disks are closely aligned with the directions of the large–scale radio jets, suggesting that it is angular momentum of the disk rather than that of the black hole that determines the direction of the radio jets. Because the disks are directly observable, we can study the disks themselves, and investigate important questions which cannot be directly addressed with observations of the smaller and unresolved central accretion disks. In this paper we summarize what has been learned to date in this rapidly unfolding new field.

scholarly journals Energy and angular momentum radiated for non-head-on binary black hole collisions

2002 ◽  
Vol 66 (10) ◽  
Author(s):  
Osvaldo Moreschi ◽  
Alejandro Perez ◽  
Luis Lehner
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Binary Black Hole

QUANTIZATION OF ENTROPY SPECTRA OF BLACK HOLES

2013 ◽  
Vol 22 (02) ◽  
pp. 1330001 ◽  
Author(s):  
YONGJOON KWON ◽  
SOONKEON NAM
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Correspondence Principle ◽  
Scattering Problem ◽  
Classical System ◽  
Quasinormal Modes ◽  
Entropy Spectrum ◽  
Total Transmission ◽  
Transmission Modes ◽  
Characteristic Modes

From the quasinormal modes (QNM) of black holes, we obtain the quantizations of the entropy and horizon area of black holes via Bohr–Sommerfeld quantization, based on Bohr's correspondence principle. For this, we identify the appropriate action variable of the classical system corresponding to a black hole. By considering the BTZ black holes in topologically massive gravity as well as Einstein gravity, it is found that the spectra of not the horizon areas but the entropies of black holes are equally spaced. We also propose that other characteristic modes of black holes, which are non-QNM or holographic QNM, can be used in quantization of entropy spectra just like QNM. From these modes, it is found that only the entropy spectrum of the warped AdS3 black hole is equally spaced as well. Furthermore, by considering a scattering problem in a black hole, we propose that the total transmission modes and total reflection modes of black holes can be regarded as characteristic modes of black holes and result in the equally spaced entropy of the Kerr and Reissner–Nordström black holes. Finally, we conclude that there is a universal behavior that the entropy spectra of various black holes are equally spaced.

Bound orbits around modified Hayward black holes

2021 ◽  
Author(s):  
Bo Gao ◽  
Xue-Mei Deng
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Gravitational Field ◽  
Periodic Orbits ◽  
Kerr Black Hole ◽  
Periodic Oscillations ◽  
Test Particles ◽  
Spin Parameter ◽  
Bound Orbits

The neutral time-like particle’s bound orbits around modified Hayward black holes have been investigated. We find that both in the marginally bound orbits (MBO) and the innermost stable circular orbits (ISCO), the test particle’s radius and its angular momentum are all more sensitive to one of the parameters [Formula: see text]. Especially, modified Hayward black holes with [Formula: see text] could mimic the same ISCO radius around the Kerr black hole with the spin parameter up to [Formula: see text]. Small [Formula: see text] could mimic the ISCO of small-spinning test particles around Schwarzschild black holes. Meanwhile, rational (periodic) orbits around modified Hayward black holes have also been studied. The epicyclic frequencies of the quasi-circular motion around modified Hayward black holes are calculated and discussed with respect to the observed Quasi-periodic oscillations (QPOs) frequencies. Our results show that rational orbits around modified Hayward black holes have different values of the energy from the ones of Schwarzschild black holes. The epicyclic frequencies in modified Hayward black holes have different frequencies from Schwarzschild and Kerr ones. These might provide hints for distinguishing modified Hayward black holes from Schwarzschild and Kerr ones by using the dynamics of time-like particles around the strong gravitational field.

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