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Dynamical Chern-Simons (DCS) theory is an extension of General Relativity in which the gravitational field is coupled to a scalar field through a parity violating term. We study perturbations of anti-de Sitter black holes and branes in such…

High Energy Physics - Theory · Physics 2011-06-20 Terence Delsate , Vitor Cardoso , Paolo Pani

In this manuscript, we provide a comprehensive study of gravitational lensing by dark compact objects predicted by a Modified Gravity (MOG) based on the Scalar-Vector-Tensor action, and the aim is to analyze new insights into the nature of…

General Relativity and Quantum Cosmology · Physics 2025-03-07 Nagina Rehman , Zoe C. S. Chan , Mubasher Jamil , Mustapha Azreg-Aïnou

Motivated by string theory scenarios, we study the optical aspect of AdS black holes in Einstein-Maxwell-dilaton theory. Concretely, we investigate and examine the shadows and the deflection angle of light rays by such cosmological black…

High Energy Physics - Theory · Physics 2025-01-27 Hajar Belmahi , Amin Mohamed Rbah

Recent observational data from the Event Horizon Telescope (EHT) collaboration provide convincing realistic evidence for the existence of black hole rotation. From a phenomenological perspective, a recently proposed stable rotating regular…

General Relativity and Quantum Cosmology · Physics 2025-01-15 Chen-Hao Xie , Yu Zhang , Qi Sun , Qi-Quan Li , Peng-Fei Duan

In this paper, we present a detailed analysis of an asymptotic, magnetically-charged, non-singular (AMCNS) black hole. By utilizing the Gauss-bonnet theorem, we aim to unravel the intricate astrophysics associated with this unique black…

General Relativity and Quantum Cosmology · Physics 2023-09-13 Yashmitha Kumaran , Ali Övgün

We study gravitational lensing by a recently proposed black hole solution in Loop Quantum Gravity. We highlight the fact that the quantum gravity corrections to the Schwarzschild metric in this model evade the `mass suppression' effects…

General Relativity and Quantum Cosmology · Physics 2015-03-16 Satyabrata Sahu , Kinjalk Lochan , D. Narasimha

Motivated by recent Event Horizon Telescope findings, we investigate constrained optics of rotating black holes in Einstein-Maxwell-scalar gravity theory. Precisely, we mainly study the parameter effects on two relevant optical concepts…

High Energy Physics - Theory · Physics 2024-11-19 Hajar Belmahi

Dynamical Chern-Simons gravity cannot be strongly constrained with current experiments because it reduces to General Relativity in the weak-field limit. This theory, however, introduces modifications in the non-linear, dynamical regime, and…

General Relativity and Quantum Cosmology · Physics 2020-01-03 Kent Yagi , Nicolas Yunes , Takahiro Tanaka

Solutions pertaining to a Kerr black hole with a flat horizon undergoing gradual rotation are explored in the context of gravitational theories modified by dynamical Chern-Simons terms with cylindrical metrics, which approach asymptotically…

General Relativity and Quantum Cosmology · Physics 2023-11-16 G. G. L. Nashed , Kazuharu Bamba

The study of astrophysical phenomena like black hole shadows is an effective approach to properly understand the modified gravity and explore its validity. Motivated by recent astrophysical observations, we consider a black hole (BH) in…

General Relativity and Quantum Cosmology · Physics 2025-03-20 Khadije Jafarzade , Zeynab Bazyar , Mubasher Jamil

In this paper, we investigate light bending in the spacetime of regular black holes with cosmic strings in weak field limits. To do so, we apply the Gauss-Bonnet theorem to the optical geometry of the black hole; and, using the…

General Relativity and Quantum Cosmology · Physics 2019-05-29 A. Övgün

We study the shadows of disformal black holes in vector-tensor Galileons modified gravity. Our analysis shows that the apparent image of the black hole in the observer's sky is non-spherical and cuspy, which is in contrast to the Kerr and…

General Relativity and Quantum Cosmology · Physics 2018-01-25 Tsvetan Vetsov , Galin Gyulchev , Stoytcho Yazadjiev

In the present work, we investigate the gravitational lensing effects of two quantum-modified black hole models recently proposed in effective quantum gravity. The light deflection angles are calculated for both the weak-field and…

General Relativity and Quantum Cosmology · Physics 2024-11-20 Hao Liu , Meng-Yun Lai , Xiao-Yin Pan , Hyat Huang , De-Cheng Zou

This study investigates the impact of the quantum-gravity correction at the third-order curvature ($c_6$) on the black hole's shadow and deflection angle on the weak field regime, both involving finite distances of observers. While the…

General Relativity and Quantum Cosmology · Physics 2024-08-20 Gaetano Lambiase , Reggie C. Pantig , Ali Övgün

Chern-Simons modified gravity is an effective extension of general relativity that captures leading-order, gravitational parity violation. Such an effective theory is motivated by anomaly cancelation in particle physics and string theory.…

High Energy Physics - Theory · Physics 2015-05-13 Stephon Alexander , Nicolas Yunes

The recent Event Horizon Telescope (EHT) observations of the M87* have led to a surge of interest in studying the shadow of black holes. Besides, investigation of time evolution and lifetime of black holes helps us to veto/restrict some…

General Relativity and Quantum Cosmology · Physics 2023-02-14 S. H. Hendi , Kh. Jafarzade , B. Eslam Panah

We study the dynamical Chern-Simons gravity as an effective quantum field theory, and discuss a broad range of its parameter space where the theory is valid. Within that validity range, we show that slowly rotating black holes acquire novel…

High Energy Physics - Theory · Physics 2022-01-12 Stephon Alexander , Gregory Gabadadze , Leah Jenks , Nicolás Yunes

In this paper, we investigate the properties of black holes within the framework of multi-fractional theories of gravity, focusing on the effects of q-derivatives and weighted derivatives. These modifications, which introduce…

General Relativity and Quantum Cosmology · Physics 2025-06-03 Reggie C. Pantig

The five dimensional Einstein-Gauss-Bonnet gravity with a negative cosmological constant becomes, for a special value of the Gauss-Bonnet coupling constant, a Chern-Simons (CS) theory of gravity. In this work we discuss the properties of…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Yves Brihaye , Eugen Radu

In this paper, we investigate the optical properties of a charged black hole in Einstein-Maxwell-scalar (EMS) theory. We evaluate the shadow cast by the black hole and obtain analytical solutions for both the radius of the photon sphere and…

General Relativity and Quantum Cosmology · Physics 2024-07-29 Ahmad Al-Badawi , Mirzabek Alloqulov , Sanjar Shaymatov , Bobomurat Ahmedov