Strong gravitational lensing, quasi-periodic oscillations and constraints from EHT observations for quantum-improved charged black hole

Niyaz Uddin Molla; Himanshu Chaudhary; G. Mustafa; Ujjal Debnath; S. K. Maurya

doi:10.1140/epjc/s10052-024-12679-9

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2024) 84: 390
https://doi.org/10.1140/epjc/s10052-024-12679-9

Regular Article - Theoretical Physics

Strong gravitational lensing, quasi-periodic oscillations and constraints from EHT observations for quantum-improved charged black hole

Niyaz Uddin Molla¹, Himanshu Chaudhary²^,3^,4, G. Mustafa⁵^,6^c, Ujjal Debnath¹ and S. K. Maurya⁷^e

¹ Department of Mathematics, Indian Institute of Engineering Science and Technology, Shibpur, 711 103, Howrah, India
² Pacif Institute of Cosmology and Selfology (PICS), 768224, Sagara, Sambalpur, Odisha, India
³ Department of Applied Mathematics, Delhi Technological University, 110042, Delhi, India
⁴ Department of Mathematics, Shyamlal College, University of Delhi, 110032, Delhi, India
⁵ Department of Physics, Zhejiang Normal University, 321004, Jinhua, People’s Republic of China
⁶ New Uzbekistan University, Movarounnahr street 1, 100000, Tashkent, Uzbekistan
⁷ Department of Mathematical and Physical Sciences, College of Arts and Sciences, University of Nizwa, 616, Nizwa, Sultanate of Oman

^c gmustafa3828@gmail.com
^e sunil@unizwa.edu.om

Received: 5 February 2024
Accepted: 13 March 2024
Published online: 12 April 2024

Abstract

We investigate strong gravitational lensing by quantum-improved charged black holes characterized by an additional parameter denoted as $ω$ $\omega$ , in addition to the mass M and charge Q. Our findings reveal that when both the parameters Q/2M and $ω / 4 M^{2}$ $\omega /4M^2$ increase simultaneously, various astrophysical consequences, such as the deflection angle $α_{D} (u)$ $\alpha _D(u)$ and angular image separation increase. Concurrently, the angular position $θ_{\infty}$ $\theta _{\infty }$ , relative magnification $r_{mag}$ $r_{mag}$ , and the time delay $Δ T_{2, 1}$ $\Delta T_{2,1}$ between the first and second relativistic images also decrease with the growing values of the parameters Q/2M and $ω / 4 M^{2}$ $\omega /4M^2$ . It is also observed that the Einstein ring $θ_{1}^{E}$ $\theta _1^E$ for the quantum-improved charged black hole is more significant than those for Schwarzschild, quantum-improved Schwarzschild, and Reisner–Nordström black holes. As with supermassive black holes such as $M 87^{*}$ $$M87^*$$ and $S g r A^{*}$ $$SgrA^*$$ , it is observed that to be a viable astrophysical black hole, the EHT results constrain the parameter space ( $ω / 4 M^{2}$ $\omega /4M^2$ , Q/2M). Remarkably, the EHT results for $S g r A^{*}$ impose more stringent limits on the parameter space of quantum-improved charged black holes compared to those established by the EHT results for $M 87^{*}$ $$M87^*$$ . We investigate the radial profiles of orbital and radial harmonic oscillation frequencies as a function of the dimensionless coupling constants and black hole mass. The main characteristics of test particle quasi-periodic oscillations close to stable circular orbits in the black hole equatorial plane are also examined. We study the positioning of resonant radii in the background of quantum-improved charged black holes for high-frequency quasi-periodic oscillations models: warped disc (WD) models, relativistic precession (RP) and its types, and epicyclic resonance (ER) and its variants.

© The Author(s) 2024

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