Article
Astronomy & Astrophysics
Philip Beltracchi, Paolo Gondolo
Summary: The article introduces a method to generate rotating solutions from nonrotating spherically-symmetric solutions using the Newman-Janis algorithm, compares the structures of the energy-momentum tensors of the two types of solutions, and looks for equations of state relating energy density and principal pressures. It ultimately identifies a unique family of stationary axisymmetric Kerr-Schild systems that obey the same equation of state in both rotating and nonrotating configurations.
Article
Astronomy & Astrophysics
Alexander Kamenshchik, Polina Petriakova
Summary: We investigate the application of the Newman-Janis algorithm to a specific regular static solution supported by a scalar field with a nonstandard kinetic term. While coordinate complexification leads to the appearance of a regular Kerr-like black hole, we encounter discrepancies in Einstein's equations within a narrow domain, primarily due to the regularization parameter. Beyond this intriguing region, the geometry corresponds to the familiar Kerr spacetime.
Article
Astronomy & Astrophysics
Di Wu, Puxun Wu, Hongwei Yu
Summary: The Kerr-(Newman)-AdS(4) black hole will be shadowless if its rotation parameter exceeds a critical value, possibly due to the appearance of null hypersurface caustics. The presence of null hypersurface caustics is irrelevant to whether an ultraspinning black hole is superentropic or not.
Article
Physics, Multidisciplinary
Yuchen Huang, Jun Tao, Peng Wang, Shuxuan Ying
Summary: Being placed in a cavity is an effective method for black holes to reach thermodynamic equilibrium. In this study, we investigate a Kerr-Newman black hole in a cavity and compare it with two simplified cases. We derive the quasi-local energy and construct the first law of thermodynamics accordingly. These black holes can undergo a van der Waals-like phase transition in a canonical ensemble, similar to that in AdS space. Furthermore, we explore the thermodynamic geometry of these black holes, revealing their sensitivity to microstructures and showing dissimilarities in a cavity.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Astronomy & Astrophysics
Ming Zhang, Jie Jiang
Summary: In the extended scalar-tensor-Gauss-Bonnet (ESTGB) field theory, a specific nonminimal coupling between a massless scalar field and the Gauss-Bonnet curvature invariant promotes the tachyonic instability of the Kerr-Newman (KN) black hole. The critical spin and charge for the onset of the spontaneous scalarization phenomenon in the KN black hole are calculated under the infinitely large coupling limit. Furthermore, an analytical formula for the coupling-strength-dependent critical existence line is obtained for the black-hole-scalar-field configuration in the finite large coupling regime. Numerical methods are used to plot threshold curves between bald KN black holes and their hairy counterparts. Interestingly, scalarization of the KN black hole is found to occur in the vanishing spin limit in the ESTGB theory.
Article
Physics, Particles & Fields
Bogeun Gwak, Naoto Kan, Bum-Hoon Lee, Hocheol Lee
Summary: This study investigates the conjectured bound on the Lyapunov exponent for a charged particle with angular motion in the Kerr-Newman-AdS black hole. The findings show that the negative cosmological constant reduces the chaotic behavior of the particle, resulting in a decrease in the Lyapunov exponent. However, the bound can be violated when the angular momenta of the black hole are turned on, particularly in an extremal black hole.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Multidisciplinary
Ran Li, Zi-Han Yu, Shu-Zheng Yang
Summary: In this paper, the scalar particle dynamics equation is modified in consideration of Lorentz symmetry breaking in the curved space-time of Kerr-Newman-Ads black hole. Based on this, the quantum tunneling radiation of the black hole is precisely modified, and the modified expressions of Hawking temperature and entropy of the black hole are obtained. In order to further obtain the correction effect of the Planck scale, this paper considers a more accurate correction method beyond the semi-classical theory, and further obtains a new expression of the black hole temperature and entropy. The physical significance of a series of new results obtained is also discussed.
INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS
(2023)
Article
Astronomy & Astrophysics
Chen-Yu Wang, Da-Shin Lee, Chi-Yong Lin
Summary: We study the null and timelike geodesics of light and the neutral particles in the exterior of Kerr-Newman black holes. We obtain the solutions of the trajectories in terms of the elliptical integrals and the Jacobian elliptic functions, and discuss the effect of the black hole's charge on the radius and the angular change of the orbits. The results have implications for observations.
Article
Astronomy & Astrophysics
Shou-Shan Bao, Qi-Xuan Xu, Hong Zhang
Summary: This paper analytically calculates the superradiant instabilities of Kerr-Newman black holes with charged or uncharged massive spin-0 fields to the next-to-leading order in the limit of alpha''rgmue1. A missing factor of 1/2 in the previous leading-order result is identified. The next-to-leading order result has a compact form and is in good agreement with existing numerical calculations. The percentage error increases with alpha, from a few percent for alpha''0.1 to about 50% for alpha''0.4. Massive neutral scalars too heavy to be produced with Kerr black hole superradiance may exist in the superradiant region of Kerr-Newman black holes.
Article
Astronomy & Astrophysics
Joshua Foo, Michael R. R. Good
Summary: This paper examines a simplified model for Hawking radiation produced by Kerr-Newman black holes, deriving the particle spectrum of the outgoing massless, scalar field and its thermal distribution. It also calculates the particle spectrum of the extremal Kerr-Newman system, demonstrating that the total emitted energy is finite.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Oscar J. C. Dias, Mahdi Godazgar, Jorge E. Santos, Gregorio Carullo, Walter Del Pozzo, Danny Laghi
Summary: The study focused on gravitational and electromagnetic perturbations of the Kerr-Newman black hole, identifying unique phenomena in the Quasinormal Mode families. The derived QNM spectra are crucial for understanding gravitational emissions in astrophysical environments and extracting observational implications of new physics scenarios.
Article
Physics, Particles & Fields
Farruh Atamurotov, Ibrar Hussain, G. Mustafa, Kimet Jusufi
Summary: We investigate the effects of different parameters on the null geodesics and shadow cast by the Kerr-Newman-Kiselev-Letelier (KNKL) black hole. We find that increasing the values of certain parameters leads to an increase in the size of the shadow and the strength of the gravitational field of the black hole. Additionally, we explore the relationship between the shadow radius and quasinormal modes for the KNKL black hole and study the emission energy rate. We also examine the effects of plasma on the shadow size and gravitational field intensity of the KNKL black hole. These findings provide valuable insights into the nature and properties of black holes.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Niyaz Uddin Molla, Ujjal Debnath
Summary: In this paper, the possibility of destroying the Kerr-Newman-Nut-Quintessence (KNNQ) black hole surrounded by the quintessence field is investigated. It is found that a near extremal KNNQ black hole can turn into a naked singularity through the interaction with test particles in both the electric and magnetic fields. However, the allowed parameter range for the particle is very narrow, suggesting that the effects of radiation, self-energy, and self-force need to be considered to prevent violation of the cosmic censorship.
MODERN PHYSICS LETTERS A
(2022)
Article
Astronomy & Astrophysics
Hai-Tian Wang, Shao-Peng Tang, Peng-Cheng Li, Yi-Zhong Fan
Summary: An analytical ringdown waveform model has been developed for charged black holes, which was precise enough to analyze gravitational wave data such as GW150914. The study constrained the charge to mass ratio of the remnant black hole and the deviation parameter of scalar-tensor vector gravity with the ringdown gravitational wave data for the first time. This approach can be applied to other binary black hole mergers with loud ringdown radiation.
Article
Physics, Multidisciplinary
Rimsha Babar, Muhammad Asgher, Riasat Ali
Summary: In this paper, the rotating Einstein-non-linear-Maxwell-Yukawa black hole solution is analyzed using the Janis-Newman algorithmic rule and complex calculations. The basic properties and the effects of spin parameter on the black hole's temperature are investigated. The corrected temperature and entropy for the black hole are also studied using vector particles tunneling strategy and checked for the effects of charge, rotation, and gravity.
Article
Astronomy & Astrophysics
Zhaoyi Xu, Xian Hou, Xiaobo Gong, Jiancheng Wang
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2018)
Article
Astronomy & Astrophysics
Zhaoyi Xu, Xian Hou, Jiancheng Wang
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2018)
Article
Astronomy & Astrophysics
Xian Hou, Zhaoyi Xu, Jiancheng Wang
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2018)
Article
Physics, Particles & Fields
Zhaoyi Xu, Xian Hou, Jiancheng Wang, Yi Liao
ADVANCES IN HIGH ENERGY PHYSICS
(2019)
Article
Astronomy & Astrophysics
Rui Li, Jiancheng Wang, Zhaoyi Xu, Xiaotong Guo
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
J. Takata, X. F. Wang, A. K. H. Kong, J. Mao, X. Hou, C. P. Hu, L. C. -C. Lin, K. L. Li, C. Y. Hui
Summary: We conducted a photometric search and identified eight potential cataclysmic variable star candidates, including six new identifications, two eclipsing systems associated with unidentified X-ray sources, and one promising candidate for polar association.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
X. Hou, M. Y. Ge, L. Ji, S. N. Zhang, Y. You, L. Tao, S. Zhang, R. Soria, H. Feng, M. Zhou, Y. L. Tuo, L. M. Song, J. C. Wang
Summary: This study conducted detailed timing and spectral analyses of the transient X-ray pulsar RX J0209.6-7427 in the Small Magellanic Cloud during its 2019 giant outburst, revealing it as a genuine PULX. The main pulsed X-ray emission of the star is determined to be from the fan beam of the accretion column, with intrinsic luminosity; its magnetic field strength is estimated from its spin evolution or transition in the accretion column structure during the outburst.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
X. Hou, Y. You, L. Ji, R. Soria, S. N. Zhang, M. Y. Ge, L. Tao, S. Zhang, H. Feng, M. Zhou, Y. L. Tuo, L. M. Song, J. C. Wang
Summary: Monte Carlo simulations reveal that the main pulsed emission of PULXs is not strongly collimated even in the presence of strong outflows. This suggests that the observed high luminosity of PULXs is indeed intrinsic, possibly indicating the existence of very strong surface magnetic fields.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
X. Hou, W. Zhang, D. F. Torres, L. Ji, J. Li
Summary: In this study, a deep search for gamma-ray emission and pulsations from 1A 0535+262 was conducted using over 13 years of Fermi-LAT data. However, no steady or pulsed gamma-ray emission was detected during the entire Fermi-LAT mission or its X-ray outbursts. As a result, the deepest gamma-ray luminosity upper limits to date were derived to be around (2.3-4.7) x 10(32) erg s(-1) at the 95% confidence level, with a ratio of L(γ) to L(X) (2-150 keV) of (1.9-3.9) x 10(-6), depending on different spectral indices assumed.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Lei Zhang, Paulo C. C. Freire, Alessandro Ridolfi, Zhichen Pan, Jiaqi Zhao, Craig O. Heinke, Jianxing Chen, Mario Cadelano, Cristina Pallanca, Xian Hou, Xiaoting Fu, Shi Dai, Erbil Guegercinoglu, Meng Guo, Jason Hessels, Jiale Hu, Guodong Li, Mengmeng Ni, Jingshan Pan, Scott M. Ransom, Qitong Ruan, Ingrid Stairs, Chao-Wei Tsai, Pei Wang, Long Wang, Na Wang, Qingdong Wu, Jianping Yuan, Jie Zhang, Weiwei Zhu, Yongkun Zhang, Di Li
Summary: We report on a comprehensive multiwavelength study of the pulsars in the globular cluster (GC) M5 and make several important discoveries, including a new compact noneclipsing black widow pulsar. The analysis of long-term radio data provides new timing solutions for the pulsars, resulting in improved measurements of proper motions, detections of Shapiro delays, and the periastron advance of certain pulsars. The binary nature of the pulsars is confirmed, with low-eccentricity binary systems and He white dwarfs as their companions. These characteristics suggest a small rate of stellar encounters per binary system in the cluster.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
Zhaoyi Xu, Xiaobo Gong, Shuang-Nan Zhang
Article
Astronomy & Astrophysics
Christopher Eckner, Xian Hou, Pasquale D. Serpico, Miles Winter, Gabrijela Zaharijas, Pierrick Martin, Mattia di Mauro, Nestor Mirabal, Jovana Petrovic, Tijana Prodanovic, Justin Vandenbroucke
ASTROPHYSICAL JOURNAL
(2018)
Article
Astronomy & Astrophysics
Kwan-Lok Li, Xian Hou, Jay Strader, Jumpei Takata, Albert K. H. Kong, Laura Chomiuk, Samuel J. Swihart, Chung Yue Hui, K. S. Cheng
ASTROPHYSICAL JOURNAL
(2018)