Strong gravitational lensing by Bardeen black holes in 4D EGB gravity: Constraints from supermassive black holes

被引:0
作者
Ul Islam, Shafqat [1 ,2 ]
Ghosh, Sushant G. [1 ,2 ]
Maharaj, Sunil D. [2 ]
机构
[1] Jamia Millia Islamia, Ctr Theoret Phys, New Delhi 110025, India
[2] Univ KwaZulu Natal, Sch Math Stat & Comp Sci, Astrophys & Cosmol Res Unit, Private Bag 54001, ZA-4000 Durban, South Africa
基金
新加坡国家研究基金会;
关键词
Gravitational lensing; Regular black hole; Event Horizon Telescope; TELESCOPE RESULTS. VI; PARAMETER-ESTIMATION; SHADOW; TENSOR; FIELD; I;
D O I
暂无
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Observation indicates that many nearby galaxies host supermassive central black holes. We use the Bardeen black holes in four-dimensional Einstein-Gauss-Bonnet (4D EGB) gravity, with additional parameters-the coupling constant (alpha) over tilde and q, charge , as central black holes in various galaxies to investigate gravitational lensing properties in strong field regime. Taking the supermassive black holes Sgr A* and M87* as the lens, we compare observable signatures of 4D EGB Bardeen black holes with those of the Schwarzschild black holes. In the case of 4D EGB Bardeen black holes we observed that he angular position theta(infinity) for Sgr A* is an element of (23.19, 25.56) mu as, whereas for M87* it is is an element of ( 17.94, 19.78) mu as. Further, the angular separation s, which is an increasing function of (alpha) over tilde and q and for Sgr A* and M87* differs significantly, respectively, in (0.032, 0.15) mu as and (0.025, 0.115) mu as. The deviations of the lensing observables Delta theta(infinity) and Delta s for 4D EGB Bardeen black hole ((alpha) over tilde = 0.9, = 0.09) from the Schwarzschild black hole, respectively, can reach up to 2.38 mu as and 0.12 mu as for Sgr A*, 1.84 mu as and 0.09 mu as for M87*. On the other hand, the relative magnification is an element of (4.66, 6.82). Considering twenty-one massive central black holes as lens, we also estimate the time delay Delta T-2,1(s) between the first and second relativistic image to find that, e.g., the time delay for Sgr A* and M87*, respectively, can reach similar to 9.86 min and similar to 16023.93 min. We also show that the existing shadow size measurements place strong constraints on the parameters considered Bardeen model. This combination of gravitational lensing and EHT results may complement comprehensive restrictions on modifications of the general relativity.
引用
收藏
页码:1710 / 1724
页数:15
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