Article
Physics, Particles & Fields
Adrian Ka-Wai Chung, Mairi Sakellariadou
Summary: A method is proposed to constrain the temperature of astrophysical black holes by detecting the inspiral phase of binary black hole coalescences. It is found that inspiraling black holes lose part of their masses during the inspiral phase, leading to faster coalescence and a correction to the orbital phase. Through gravitational wave detection, the temperature of inspiraling black holes is constrained to be less than about 10^(9) K, indicating no evidence for strong quantum-gravity effects during the detection of the inspiral phase.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Manuel Ettengruber
Summary: This paper investigates the general features of the neutrino sector in TeV scale quantum gravity theories, such as the Arkani-Hamed-Dimopoulos-Dvali (ADD) model and many species theory. It explores the mechanism of generating small neutrino masses and extends it to the realistic three-flavor case. It also presents a procedure for diagonalizing a mass matrix generated by these theories and finding the Standard Model flavor eigenstates. The general approach developed in this paper is applied to specific scenarios within ADD and many species theory to calculate their effects on neutrino oscillations and the unitarity of the lepton mixing matrix. Finally, it provides a brief overview of phenomenology that can be potentially tested by current neutrino experiments.
Article
Physics, Nuclear
Wei Zeng, Yi Ling, Qing-Quan Jiang
Summary: We investigate the photon sphere and marginally stable circular orbit of regular black holes with sub-Planckian curvature and a Minkowskian core. The stability and location of these orbits are analyzed, and a comparison with other black holes is made. We also discuss the potential of distinguishing between different types of black holes through astronomical observations. Furthermore, we present observational constraints on the deviation parameter for such regular black holes using observed data from the black hole M87*.
Review
Multidisciplinary Sciences
Bakhtiyor Narzilloev, Bobomurat Ahmedov
Summary: This work reviews the investigation of electromagnetic, optical, and energetic properties of astrophysical and galactic black holes and surrounding matter. Astrophysical applications of theoretical models to describe observed phenomena are discussed. It has been shown that observational data strongly depends on the structure and evolution of the accretion disk surrounding the black hole. The simulated images of supermassive black holes obtained are in agreement with the observations, and the high energetic activity from supermassive black holes is consistent with observed cosmic rays.
Article
Astronomy & Astrophysics
Georgios Antoniou, Caio F. B. Macedo, Ryan McManus, Thomas P. Sotiriou
Summary: The study investigates the radial stability of scalarized black-hole solutions and shows that Ricci coupling has a positive impact on their stability. In addition, it is found that Ricci coupling significantly reduces the region where hyperbolicity is lost in the equation governing linear, radial perturbations.
Article
Astronomy & Astrophysics
V De Luca, G. Franciolini, P. Pani, A. Riotto
Summary: The study suggests that black hole merger events may be explained by a combination of astrophysical and primordial black holes, with the mixed model having strong statistical evidence in support. It is found that astrophysical mergers account for roughly four times the amount of primordial black hole events, and predicts that future third-generation detectors will detect hundreds of mergers from primordial black hole binaries at higher redshifts.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Simone S. Bavera, Gabriele Franciolini, Giulia Cusin, Antonio Riotto, Michael Zevin, Tassos Fragos
Summary: This study demonstrates how to add an additional and independent constraint to model selection by using the stochastic gravitational-wave background. The predicted results are consistent with current background limits and can be detectable by third-generation detectors.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
A. V. Plavin, Y. Y. Kovalev, Yu. A. Kovalev, S. V. Troitsky
Summary: Recent research suggests that high-energy neutrinos detected by IceCube may be produced in the central regions of radio-bright blazars, interacting with X-ray self-Compton photons. Independent analysis of blazars and IceCube data shows significance, potentially explaining the source of the entire IceCube astrophysical neutrino flux.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Lam Hui, Austin Joyce, Riccardo Penco, Luca Santoni, Adam R. Solomon
Summary: This article investigates the tidal response of asymptotically flat black holes in general relativity and finds that the response is zero due to the linear symmetries governing static perturbations around the black holes. These symmetries have a geometric origin and a ladder structure that can be used to construct the complete set of solutions and derive their general properties. It is shown that solutions spontaneously break the symmetries when they decay with radius and respect the symmetries when they are regular at the horizon. These properties imply that tidal response coefficients, including Love numbers, vanish, which is consistent with the absence of black holes with linear hair. Furthermore, the manifestation of these symmetries in the effective point particle description of a black hole is discussed, demonstrating that couplings associated with non-trivial tidal response and scalar hair must vanish for the symmetries to be preserved.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Daniel G. Figueroa, Sami Raatikainen, Syksy Rasanen, Eemeli Tomberg
Summary: This study investigates the impact of stochastic noise on the generation of primordial black hole seeds in ultra-slow-roll inflation. By considering the non-linearity of the system and the dependence of noise on inflaton perturbations, the study captures the non-Markovian nature of the dynamics. The results show that stochastic effects can significantly enhance the abundance of primordial black holes.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Cosimo Bambi, Dejan Stojkovic
Summary: Wormholes are hypothetical structures in spacetime with non-trivial topology that challenge the possibility of their existence. This article provides a concise review of past and current efforts to search for astrophysical wormholes in the Universe.
Article
Astronomy & Astrophysics
Gabriele Bozzola, Vasileios Paschalidis
Summary: Unlike energy and angular momentum, electric charge is conserved in mergers of charged black holes. This paper investigates the formation of naked singularities in quasicircular mergers of charged binary black holes. The theoretical model is extended to estimate the properties of the remnant left by these mergers, and numerical-relativity simulations validate the model's accuracy. The theoretical model suggests that while naked singularities cannot form following these mergers, remnants that are arbitrarily close to the extremal limit can be produced.
Article
Astronomy & Astrophysics
Diptimoy Ghosh, Arun Thalapillil, Farman Ullah
Summary: We discuss various potential astrophysical signatures and constraints on magnetically charged black holes of different masses, highlighting their immense electromagnetic fields and their potential as windows to fundamental physics. The investigation includes limits on charges, stable orbits, horizons, galactic magnetic fields and dark matter measurements, electromagnetic fluxes, and gravitational wave emissions during binary inspirals. The distinct features of electromagnetic emissions and gravitational waveform evolution during binary inspirals are also considered.
Article
Physics, Multidisciplinary
Marcus A. Khuri, Jordan F. Rainone
Summary: We present the first examples of formally asymptotically flat black hole solutions with horizons of general lens space topology L(p, q). These solutions are five-dimensional static or stationary spacetimes that are regular on and outside the event horizon, and supported by Kaluza-Klein matter fields. Additionally, we obtain new examples of regular gravitational instantons in higher dimensions.
PHYSICAL REVIEW LETTERS
(2023)
Article
Astronomy & Astrophysics
Di Wu
Summary: In this paper, the topological numbers for singly rotating Kerr black holes in all dimensions and the four-dimensional Kerr-Newman black hole are investigated. It is found that the rotation parameter has a significant effect on the topological number for uncharged black holes, and the dimension of spacetimes also has a remarkable effect on the topological number for rotating black holes. Additionally, it is discovered that the topological numbers of the four-dimensional Kerr and Kerr-Newman black holes are the same, suggesting that the electric charge parameter does not affect the topological number of rotating black holes. The research provides more evidence for the conjecture proposed in Wei et al. [Phys. Rev. Lett., 129, 191101(2022)] that all black hole solutions should be separated into three different topological classes, at least in the pure Einstein-Maxwell gravity theory.
Article
Astronomy & Astrophysics
Steven B. Giddings
CLASSICAL AND QUANTUM GRAVITY
(2011)
Article
Astronomy & Astrophysics
Vitor Cardoso, Leonardo Gualtieri, Carlos Herdeiro, Ulrich Sperhake, Paul M. Chesler, Luis Lehner, Seong Chan Park, Harvey S. Reall, Carlos F. Sopuerta, Daniela Alic, Oscar J. C. Dias, Roberto Emparan, Valeria Ferrari, Steven B. Giddings, Mahdi Godazgar, Ruth Gregory, Veronika E. Hubeny, Akihiro Ishibashi, Greg Landsberg, Carlos O. Lousto, David Mateos, Vicki Moeller, Hirotada Okawa, Paolo Pani, M. Andy Parker, Frans Pretorius, Masaru Shibata, Hajime Sotani, Toby Wiseman, Helvi Witek, Nicolas Yunes, Miguel Zilhao
CLASSICAL AND QUANTUM GRAVITY
(2012)
Article
Physics, Multidisciplinary
Steven B. Giddings
FOUNDATIONS OF PHYSICS
(2013)
Article
Astronomy & Astrophysics
Steven B. Giddings, Martin S. Sloth
Article
Astronomy & Astrophysics
Steven B. Giddings
Article
Astronomy & Astrophysics
Steven B. Giddings
Article
Astronomy & Astrophysics
Steven B. Giddings, Yinbo Shi
Article
Physics, Multidisciplinary
Steven B. Giddings
FOUNDATIONS OF PHYSICS
(2019)
Review
Multidisciplinary Sciences
Steven B. Giddings
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2019)
Article
Astronomy & Astrophysics
Steven B. Giddings, Julie Perkins
Summary: In this article, a general description of the evolving quantum state of a Schwarzschild black hole is given using the quantum field theory approximation. The description depends on the choice of time slices, coordinates on the slices and mode bases. The evolving state can simplify the analysis and has connections to information-theoretic investigation of black hole evolution.
Article
Astronomy & Astrophysics
Steven B. Giddings
Article
Astronomy & Astrophysics
Steven B. Giddings, Sean Weinberg
Article
Astronomy & Astrophysics
William Donnelly, Steven B. Giddings
Article
Astronomy & Astrophysics
Mirah Gary, Steven B. Giddings
Article
Astronomy & Astrophysics
William Donnelly, Steven B. Giddings