Article
Astronomy & Astrophysics
Moises Bravo-Gaete, Maria Montserrat Juarez-Aubry, Gerardo Velazquez Rodriguez
Summary: In this work, we study the existence of asymptotically Lifshitz black holes in four dimensions with a negative cosmological constant. We consider two scenarios, including dilatonic fields and a nonminimally coupled scalar field. We find solutions for specific values of the dynamical exponent, as well as additional solutions in the limiting case. We also study the thermodynamics of these new solutions and find that they satisfy the first law of thermodynamics and the Smarr relation.
Article
Astronomy & Astrophysics
Jonathan Cheyne, David Mattingly
Summary: Numerical solutions were found for 2 + 1 asymptotically Lifshitz universal horizon solutions in Hofava-Lifshitz gravity for dynamical exponents z = 2 through z = 16. It was discovered that there exists a thermodynamical first law for all z, and that the energy-entropy relation or Smarr formula is satisfied for universal horizons with the correct z scaling.
Article
Physics, Particles & Fields
Alfredo Herrera-Aguilar, Jhony A. Herrera-Mendoza, Daniel F. Higuita-Borja
Summary: In this study, we introduce a spinning black hole solution in d dimensions with the maximal number of rotation parameters in the context of the Einstein-Maxwell-Dilaton theory. The rotating nature of the black hole solution is verified through quasi-local analysis of conserved charges and thermodynamical analysis. The thermodynamic stability of the solution is further studied from both local and global perspectives, revealing some interesting properties of the obtained rotating black hole spacetime.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Edgardo Franzin, Stefano Liberati, Jacopo Mazza, Alex Simpson, Matt Visser
Summary: The recent development of rotating black-bounce-Kerr spacetimes has sparked interest in exploring black-bounce variants of the entire Kerr-Newman family. Specifically focusing on black-bounce-Reissner-Nordstrom and black-bounce-Kerr-Newman spacetimes, researchers have considered their deviation from the Kerr-Newman family in a controlled manner, discussing the existence of Killing tensor and the theoretical impact of non-zero electric charge on astrophysical black holes. Additionally, they have examined the interesting matter/energy content required by the black-bounce-Kerr-Newman solution within the framework of general relativity.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Martin Enriquez Rojo, Till Heckelbacher
Summary: This paper extends the study of asymptotically decelerating spatially flat FLRW spacetimes, showing that a certain class of metrics in this context is governed by the asymptotic algebra bms(s), a one-parameter deformation of bms. By introducing a holographic flow, the holographic algebras in FLRW can be related to their flat counterparts. Additionally, a logarithmic ansatz is introduced to account for cosmological black holes, which do not generally satisfy the peeling property but preserve the asymptotic algebra.
Article
Physics, Particles & Fields
Deniz O. Devecioglu
Summary: In this work, the holographic stress tensor of colored Lifshitz spacetimes was computed using the Einstein-Yang-Mills model, showing that the stress tensor is finite and obeys scaling and diffeomorphism Ward identities. The energy density and spatial stress tensor of numerical black hole solutions were evaluated to demonstrate the validity of the alternative Smarr relation and the first law of thermodynamics for hairy black holes without a global Yang-Mills charge.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Yi Yang, Dong Liu, Zhaoyi Xu, Yujia Xing, Shurui Wu, Zheng-Wen Long
Summary: The study discusses the importance of echo signals in understanding the characteristics of novel black-bounce spacetimes and analyzes the features of echo signals in detail. The research found that in novel black-bounce spacetimes, echo signals only appear when the parameter a > 2M, and they will transform into the quasinormal ringdown of two-way traversable wormholes as the parameter a increases.
Article
Astronomy & Astrophysics
Fatemeh Naeimipour, Behrouz Mirza, Soudabe Nasirimoghadam
Summary: In this study, two types of Yang-Mills-dilaton black hole solutions were obtained in both Lifshitz and hyperscaling violation spacetimes, with differences in thermodynamic properties and stability. It was found that for negative values of the hyperscaling violation parameter, the thermal stability of the solutions exhibited some special cases.
Article
Astronomy & Astrophysics
Zeus S. Moreira, Rafael P. Bernar, Luis C. B. Crispino
Summary: The study analyzes the power radiated by a scalar particle in circular geodesic orbits around a Schwarzschild black hole using confluent Heun functions to represent radial scalar field modes. The emitted power is obtained using Quantum Field Theory in Curved Spacetimes at tree level, with excellent agreement found when comparing analytical and numerical results. The method of using confluent Heun functions to describe radial modes can also be extended to fields of different spins in other black hole spacetimes.
Article
Astronomy & Astrophysics
Nuno M. Santos, Carlos A. R. Herdeiro, Eugen Radu
Summary: This study finds that in some models, scalarized BHs bifurcating from Reissner-Nordstrom and spinning BHs with synchronized hair bifurcating from Kerr do not have local thermodynamic stability.
Article
Astronomy & Astrophysics
Okan Gunel, Ulf Lindstrom, Ozgur Sarioglu
Summary: We construct an asymptotic conserved charge for a current defined by Killing-Yano tensors, and calculate the corresponding charges for Kerr, AdS-Kerr, Myers-Perry, and Gibbons-Lu-Page-Pope black holes. The new charges are all proportional to the angular momenta of their parent black holes.
Article
Astronomy & Astrophysics
Lucas G. Collodel, Daniela D. Doneva, Stoytcho S. Yazadjiev
Summary: In this work, we analyze the solutions of Kerr black holes with scalar hair that are of special interest for extreme mass ratio inspirals (EMRIs) in gravitational wave events. The off-center distribution of energy density in these spacetimes causes nonmonotonic behavior in the metric functions, which has a significant impact on the orbital parameters and signals from EMRIs. By investigating circular orbit parameters, we identify qualitative features in the signals that are distinct from Kerr black holes, and we simulate inspirals using the quadrupole formula approximation. We find that the emitted signal frequencies exhibit nonmonotonic behavior, including backward chirp, and can fall below the sensitivity range of LISA in some cases. Additionally, we present waveforms of a noncircular EMRI where the compact object follows a geodesic motion typically associated with spacetimes containing a static ring.
Article
Astronomy & Astrophysics
Naritaka Oshita, Niayesh Afshordi, Shinji Mukohyama
Summary: This study investigates the ringdown waveform and reflectivity of a Lifshitz scalar field around a fixed Schwarzschild black hole, finding that Lifshitz waves scattered by the black hole exhibit superradiance due to Lorentz breaking terms leading to superluminal propagation. This can allow Lifshitz waves to carry additional positive energy to infinity while leaving negative energy inside the Killing horizon, similar to the Penrose process in Kerr spacetime. The study also observes the emergence of long-lived quasinormal modes and drastic modifications to the greybody factor of a microscopic black hole with Hawking temperature comparable to the Lifshitz energy scale.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Mathematical
Athanasios Chatzikaleas, Arick Shao
Summary: We reconsider the unique continuation property for a general class of tensorial Klein-Gordon equations on asymptotically anti-de-Sitter spacetimes. We generalize previous results by replacing the geometric assumption on the conformal boundary with a more general and gauge invariant criterion, applying the new unique continuation property to a larger class of domains, and connecting the failure of our criterion to the existence of certain null geodesics near the conformal boundary.
COMMUNICATIONS IN MATHEMATICAL PHYSICS
(2022)
Article
Astronomy & Astrophysics
Michael T. N. Imseis, Abdulrahim Al Balushi, Robert B. Mann
Summary: This paper studies the light-like foliation of the Kerr-Newman-AdS black hole geometry and compares it with other black holes. It is found that caustics develop inside the inner horizon of the Kerr-Newman-AdS black hole, in contrast to the Kerr-AdS case. The study also explores the properties of ultra-spinning black holes and constructs Kruskal coordinates for them.
CLASSICAL AND QUANTUM GRAVITY
(2021)