Microlensing bias on the detection of strong lensing gravitational wave  

作　　者：Xikai Shan Xuechun Chen Bin Hu Guoliang Li 

机构地区：[1]Institute for Frontier in Astronomy and Astrophysics,Beijing Normal University,Beijing 102206,China [2]Department of Astronomy,Beijing Normal University,Beijing 100875,China [3]Purple Mountain Observatory,Chinese Academy of Sciences,Nanjing 210023,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第6期156-165,共10页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Key R&D Program of China(Grant No.2021YFC2203001);support from Project funded by China Postdoctoral Science Foundation(Grant No.2023M730298)。

摘　　要：Identifying strong lensing gravitational wave(SLGW)events is of utmost importance in astrophysics as we approach the historic first detection of SLGW amidst the growing number of gravitational wave(GW)events.Currently,one crucial method for identifying SLGW signals involves assessing the overlap of parameters between two GWs.However,the distribution of discrete matter,such as stars and sub-halos,within the strong lensing galaxy can imprint a wave optical(WO)effect on the SLGW waveform.These frequency dependent imprints introduce biases in parameter estimation and impact SLGW identification.In this study,we assess the influence of the stellar microlensing field embedded in a strong lensing galaxy.Our findings demonstrate that the WO effect reduces the detection efficiency of SLGW by 5%-50%for various false alarm probabilities per pair(FAPper pair).Specifically,at an FAPper pairof 10^(-5),the detection efficiency decreases from~10%to~5%.Consequently,the presence of the microlensing field can result in missing half of the strong lensing candidates.Additionally,the microlensing WO effect introduces a noticeable bias in intrinsic parameters,particularly for chirp mass and mass ratio.However,it has tiny influence on extrinsic parameters.Considering all parameters,~30%of events exhibit a 1σparameter bias,~12%exhibit a 2σparameter bias,and~5%exhibit a 3σparameter bias.

关 键 词：gravitational wave gravitational strong lensing gravitational micro lensing wave optical effect 

分 类 号：P142.84[天文地球—天体物理]