scholarly journals Quasi-normal modes of static spherically symmetric black holes in f(R) theory

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Sayak Datta ◽  
Sukanta Bose
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Gravitational Wave ◽  
Normal Modes ◽  
Einstein Frame ◽  
Spherically Symmetric ◽  
Inhomogeneous Term ◽  
Binary Black Hole ◽  
Special Case

AbstractWe study the quasi-normal modes (QNMs) of static, spherically symmetric black holes in f(R) theories. We show how these modes in theories with non-trivial f(R) are fundamentally different from those in general relativity. In the special case of $$f(R) = \alpha R^2$$f(R)=αR2 theories, it has been recently argued that iso-spectrality between scalar and vector modes breaks down. Here, we show that such a break down is quite general across all f(R) theories, as long as they satisfy $$f''(0)/(1+f''(0)) \ne 0$$f′′(0)/(1+f′′(0))≠0, where a prime denotes derivative of the function with respect to its argument. We specifically discuss the origin of the breaking of isospectrality. We also show that along with this breaking the QNMs receive a correction that arises when $$f''(0)/(1+f'(0)) \ne 0$$f′′(0)/(1+f′(0))≠0 owing to the inhomogeneous term that it introduces in the mode equation. We discuss how these differences affect the “ringdown” phase of binary black hole mergers and the possibility of constraining f(R) models with gravitational-wave observations. We also find that even though the iso-spectrality is broken in f(R) theories, in general, nevertheless in the corresponding scalar-tensor theories in the Einstein frame it is unbroken.

scholarly journals The astrophysical odds of GW151216

2020 ◽  
Vol 498 (2) ◽  
pp. 1905-1910 ◽  
Author(s):  
Gregory Ashton ◽  
Eric Thrane
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Wave ◽  
Bayesian Method ◽  
Massive Stars ◽  
Stellar Mass ◽  
Population Analyses ◽  
Wave Detection ◽  
Binary Black Hole ◽  
Bona Fide

ABSTRACT The gravitational-wave candidate GW151216 is a proposed binary black hole event from the first observing run of the Advanced LIGO detectors. Not identified as a bona fide signal by the LIGO–Virgo collaboration, there is disagreement as to its authenticity, which is quantified by pastro, the probability that the event is astrophysical in origin. Previous estimates of pastro from different groups range from 0.18 to 0.71, making it unclear whether this event should be included in population analyses, which typically require pastro > 0.5. Whether GW151216 is an astrophysical signal or not has implications for the population properties of stellar-mass black holes and hence the evolution of massive stars. Using the astrophysical odds, a Bayesian method that uses the signal coherence between detectors and a parametrized model of non-astrophysical detector noise, we find that pastro = 0.03, suggesting that GW151216 is unlikely to be a genuine signal. We also analyse GW150914 (the first gravitational-wave detection) and GW151012 (initially considered to be an ambiguous detection) and find pastro values of 1 and 0.997, respectively. We argue that the astrophysical odds presented here improve upon traditional methods for distinguishing signals from noise.

scholarly journals Upper limits on the temperature of inspiraling astrophysical black holes

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Adrian Ka-Wai Chung ◽  
Mairi Sakellariadou
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Wave ◽  
Binary Black Hole ◽  
Upper Limits ◽  
Gravity Effects ◽  
Wave Event ◽  
Orbital Phase ◽  
Intrinsic Radiation ◽  
Peak Luminosity

AbstractWe present a method to constrain the temperature of astrophysical black holes through detecting the inspiral phase of binary black hole coalescences. At sufficient separation, inspiraling black holes can be regarded as isolated objects, hence their temperature can still be defined. Due to their intrinsic radiation, inspiraling black holes lose part of their masses during the inspiral phase. As a result, coalescence speeds up, introducing a correction to the orbital phase. We show that this dephasing may allow us to constrain the temperature of inspiraling black holes through gravitational-wave detection. Using the binary black-hole coalescences of the first two observing runs of the Advanced LIGO and Virgo detectors, we constrain the temperature of parental black holes to be less than about $$ 10^9 $$ 10 9  K. Such a constraint corresponds to luminosity of about $$ 10^{-16} M_{\odot }~\mathrm{s}^{-1} $$ 10 - 16 M ⊙ s - 1 for a black hole of $$ 20 M_{\odot } $$ 20 M ⊙ , which is about 20 orders of magnitude below the peak luminosity of the corresponding gravitational-wave event, indicating no evidence for strong quantum-gravity effects through the detection of the inspiral phase.

AN ANSWER TO THE MAIN BLACK HOLE PATHOLOGY: FORMING NONSINGULAR BLACK HOLES FROM DUST COLLAPSE

2009 ◽  
Vol 18 (14) ◽  
pp. 2221-2229 ◽  
Author(s):  
R. MAIER ◽  
I. DAMIÃO SOARES
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Event Horizon ◽  
Nonlinear Resonance ◽  
Space Time ◽  
Low Energy ◽  
Spherically Symmetric ◽  
Energy Limit ◽  
Exterior Space

The dynamics of gravitational collapse is examined in the realm of string-based formalism of D-branes which encompasses general relativity as a low energy limit. A complete analytical solution is given to the spherically symmetric collapse of a pure dust star, including its matching with a corrected Schwarzschild exterior space–time. The collapse forms a black hole (an exterior event horizon) enclosing not a singularity but perpetually bouncing matter in the infinite chain of space–time maximal analytical extensions inside the outer event horizon. This chain of analytical extensions has a structure analogous to that of the Reissner–Nordstrom solution. The interior trapped bouncing matter has the possibility of being expelled by disruptive nonlinear resonance mechanisms.

scholarly journals Searching for eccentricity: signatures of dynamical formation in the first gravitational-wave transient catalogue of LIGO and Virgo

2019 ◽  
Vol 490 (4) ◽  
pp. 5210-5216 ◽  
Author(s):  
Isobel M Romero-Shaw ◽  
Paul D Lasky ◽  
Eric Thrane
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Bayesian Inference ◽  
Gravitational Wave ◽  
Globular Clusters ◽  
Reference Frequency ◽  
Binary Black Holes ◽  
Binary Black Hole ◽  
Upper Limits ◽  
Formation History

ABSTRACT Binary black holes are thought to form primarily via two channels: isolated evolution and dynamical formation. The component masses, spins, and eccentricity of a binary black hole system provide clues to its formation history. We focus on eccentricity, which can be a signature of dynamical formation. Employing the spin-aligned eccentric waveform model seobnre, we perform Bayesian inference to measure the eccentricity of binary black hole merger events in the first gravitational-wave transient catalogue of LIGO and Virgo. We find that all of these events are consistent with zero eccentricity. We set upper limits on eccentricity ranging from 0.02 to 0.05 with 90  per cent confidence at a reference frequency of $10\, {\rm Hz}$. These upper limits do not significantly constrain the fraction of LIGO–Virgo events formed dynamically in globular clusters, because only $\sim 5{{\ \rm per\ cent}}$ are expected to merge with measurable eccentricity. However, with the gravitational-wave transient catalogue set to expand dramatically over the coming months, it may soon be possible to significantly constrain the fraction of mergers taking place in globular clusters using eccentricity measurements.

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 Quantum Black Holes in the Sky

Universe ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 43 ◽  
Author(s):  
Jahed Abedi ◽  
Niayesh Afshordi ◽  
Naritaka Oshita ◽  
Qingwen Wang
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Review Article ◽  
Compact Objects ◽  
Theoretical Underpinning ◽  
The Past ◽  
Einstein’S General Relativity

Black Holes are possibly the most enigmatic objects in our universe. From their detection in gravitational waves upon their mergers, to their snapshot eating at the centres of galaxies, black hole astrophysics has undergone an observational renaissance in the past four years. Nevertheless, they remain active playgrounds for strong gravity and quantum effects, where novel aspects of the elusive theory of quantum gravity may be hard at work. In this review article, we provide an overview of the strong motivations for why “Quantum Black Holes” may be radically different from their classical counterparts in Einstein’s General Relativity. We then discuss the observational signatures of quantum black holes, focusing on gravitational wave echoes as smoking guns for quantum horizons (or exotic compact objects), which have led to significant recent excitement and activity. We review the theoretical underpinning of gravitational wave echoes and critically examine the seemingly contradictory observational claims regarding their (non-)existence. Finally, we discuss the future theoretical and observational landscape for unraveling the “Quantum Black Holes in the Sky”.

scholarly journals Quasi-normal modes of near-extremal black holes in generalized spherically symmetric spacetime and strong cosmic censorship conjecture

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Piyabut Burikham ◽  
Supakchai Ponglertsakul ◽  
Taum Wuthicharn
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Normal Modes ◽  
Cosmic Censorship ◽  
Analytic Formula ◽  
Spherically Symmetric ◽  
Black Hole Background ◽  
Strong Cosmic Censorship ◽  
Black Hole Spacetime ◽  
Symmetric Black Hole

AbstractA number of near-extremal conditions are utilized to simplify the equation of motion of the neutral scalar perturbations in generalized spherically symmetric black hole background into a differential equation with the Pöschl–Teller potential. An analytic formula for quasinormal frequencies is obtained. The analytic formula is then used to investigate strong cosmic censorship conjectures (SCC) of the generalized black hole spacetime for the smooth initial data. The Christodoulou version of the SCC is found to be violated for certain regions of the black hole parameter space including the black holes in general relativity while the $$C^{1}$$ C 1 version of the SCC is always valid.

scholarly journals Probingintermediate-mass black holes in M87 through multiwavelength gravitational wave observations

2020 ◽  
Vol 495 (1) ◽  
pp. 536-543 ◽  
Author(s):  
Razieh Emami ◽  
Abraham Loeb
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Wave ◽  
Parameter Space ◽  
Intermediate Mass ◽  
Triple Systems ◽  
Supermassive Black Hole ◽  
Binary Black Hole ◽  
Wide Range

ABSTRACT We analyse triple systems composed of the supermassive black hole (SMBH) near the centre of M87 and a pair of black holes (BHs) with masses in the range of $10{-}10^3\, {\rm M}_{\odot }$. We consider the post Newtonian precession as well as the Kozai–Lidov interactions at the quadruple and octupole levels in modelling the evolution of binary black hole (BBH) under the influence of the SMBH. Kozai–Lidov oscillations enhance the gravitational wave (GW) signal in some portions of the parameter space. We identify frequency peaks and examine the detectability of GWs with LISA as well as future observatories such as μAres and DECIGO. We show examples in which GW signal can be observed with a few or all of these detectors. Multiwavelength GW spectroscopy holds the potential to discover stellar to intermediate mass BHs near the centre of M87. We estimate the rate, Γ, of collisions between the BBHs and fly-by stars at the centre of M87. Our calculation suggest $\Gamma \lt 10\, \rm {Gyr}^{-1}$ for a wide range of the mass and semimajor axes of the inner binary.

scholarly journals ARE BLACK HOLES IN BRANS-DICKE THEORY PRECISELY THE SAME AS IN GENERAL RELATIVITY?

1993 ◽  
Vol 02 (04) ◽  
pp. 451-462 ◽  
Author(s):  
M. CAMPANELLI ◽  
C.O. LOUSTO
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Solar System ◽  
Parameter Family ◽  
Spherically Symmetric ◽  
Field Equations

We study a three-parameter family of solutions of the Brans-Dicke field equations. They are static and spherically symmetric. We find the range of parameters for which this solution represents a black hole different from the Schwarzschild one. We find a subfamily of solutions which agrees with experiments and observations in the solar system. We discuss some astrophysical applications and the consequences on the “no hair” theorems for black holes.

Geometrodynamics of Lovelock black holes

2013 ◽  
Vol 91 (6) ◽  
pp. 461-462
Author(s):  
Gabor Kunstatter
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Fast Track ◽  
Mass Function ◽  
Spherically Symmetric ◽  
Hole Formation ◽  
Lovelock Gravity ◽  
Higher Dimensional ◽  
Classical Quantum

Lovelock gravity is arguably the most natural higher curvature, higher dimensional generalization of Einstein's theory of gravity. As shown in a previous paper (Kunstatter et al. arXiv:1210.1566; Kunstatter et al. Classical Quantum Gravity, 29, 092001 (2012) (Fast Track); arXiv:1201.4904.), the Hamiltonian for spherically symmetric Lovelock gravity is as simple as that of general relativity when written in terms of geometrodynamical variables (i.e., the areal radius and mass function). This result paves the way to the study of critical phenomena in black hole formation and the quantum mechanics of Lovelock black holes.

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