Shadows and gravitational weak lensing by the Schwarzschild black hole in the string cloud background with quintessential field  

作　　者：G.Mustafa Farruh Atamurotov Ibrar Hussain Sanjar Shaymatov Ali Övgün 

机构地区：[1]Department of Physics,Zhejiang Normal University,Jinhua 321004,China [2]Inha University in Tashkent,Ziyolilar 9,Tashkent 100170,Uzbekistan [3]Akfa University,Milliy Bog Street 264,Tashkent 111221,Uzbekistan [4]National University of Uzbekistan,Tashkent 100174,Uzbekistan [5]Tashkent State Technical University,Tashkent 100095,Uzbekistan [6]School of Electrical Engineering and Computer Science,National University of Sciences and Technology,H-12,Islamabad,Pakistan [7]Samarkand State University,University Avenue 15,Samarkand 140104,Uzbekistan [8]Ulugh Beg Astronomical Institute,Astronomicheskaya 33,Tashkent 100052,Uzbekistan [9]Institute of Fundamental and Applied Research,National Research University TIIAME,Kori Niyoziy 39,Tashkent 100000,Uzbekistan [10]Physics Department,Eastern Mediterranean University,Famagusta,99628 North Cyprus via Mersin 10,Turkey

出　　处：《Chinese Physics C》2022年第12期321-332,共12页中国物理C（英文版）

基　　金：the Grant No.ZC304022919 to support his Postdoctoral Fellowship at Zhejiang Normal University;the support of Inha University in Tashkent and research work has been supported by the Visitor Research Fellowship at Zhejiang Normal University;supported by Research Grant FZ-20200929344,F-FA-2021-510 and F-FA-2021-432 of the Uzbekistan Ministry for Innovative Development。

摘　　要：In this study,we observe that,in the presence of the string cloud parameter a and the quintessence parameterγ,with the equation of state parameter,ω_(q) = -2/3the radius of the shadow of the Schwarzschild black hole increases as compared with that in the pure Schwarzschild black hole case.The existence of both quintessential dark energy and the cloud of strings increases the shadow size;hence,the strength of the gravitational field around the Schwarzschild black hole increases.Using the data collected by the Event Horizon Telescope(EHT)collaboration for M87*and Sgr A*,we obtain upper bounds on the values of a andγ.Further,we see the effects of a andγon the rate of emission energy for the Schwarzschild black hole.We notice that the rate of emission energy is higher in the presence of clouds of strings and quintessence.Moreover,we study the weak deflection angle using the Gauss-Bonnet theorem.We show the influence of a andγon the weak deflection angle.We notice that both a andγincrease the deflection angleα.

关 键 词：shadow gravitational Lensing string cloud QUINTESSENCE Schwarzschild black hole 

分 类 号：P145.8[天文地球—天体物理]