The elliptical power-law model of the mass in a galaxy is widely used in strong gravitational lensing analyses.However,the distribution of mass in real galaxies is more complex.We quantify the biases due to this model mismatch by simulating and then analyzing mock Hubble Space Telescope imaging of lenses with mass distributions inferred from SDSS-MaNGA stellar dynamics data.We find accurate recovery of source galaxy morphology,except for a slight tendency to infer sources to be more compact than their true size.The Einstein radius of the lens is also robustly recovered with 0.1％accuracy,as is the global density slope,with 2.5％relative systematic error,compared to the 3.4％intrinsic dispersion.However,asymmetry in real lenses also leads to a spurious fitted"external shear"with typical strength γext=0.015.Furthermore,time delays inferred from lens modeling without measurements of stellar dynamics are typically underestimated by～5％.Using such measurements from a sub-sample of 37 lenses would bias measurements of the Hubble constant Ho by～9％.Although this work is based on a particular set of MaNGA galaxies,and the specific value of the detected biases may change for another set of strong lenses,our results strongly suggest the next generation cosmography needs to use more complex lens mass models.

Xiaoyue Cao;Ran Li;J.W.Nightingale;Richard Massey;Andrew Robertson;Carlos S.Frenk;Aristeidis Amvrosiadis;Nicola C.Amorisco;Qiuhan He;Amy Etherington;Shaun Cole;Kai Zhu

National Astronomical Observatories,Chinese Academy of Sciences,20A Datun Road,Chaoyang District,Beijing 100012,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China;Institute for Computational Cosmology,Physics Department,Durham University,South Road,Durham,DH1 3LE,United Kingdom

天文和天体物理学研究

[1]Xiaoyue Cao;Ran Li;J.W.Nightingale;Richard Massey;Andrew Robertson;Carlos S.Frenk;Aristeidis Amvrosiadis;Nicola C.Amorisco;Qiuhan He;Amy Etherington;Shaun Cole;Kai Zhu-.Systematic Errors Induced by the Elliptical Power-law model in Galaxy-Galaxy Strong Lens Modeling)[J].天文和天体物理学研究,2022(02):143-172

Elliptical,MaNGA,cosmography

Systematic,Errors,Induced,by,Power,law,Galaxy,Strong,Lens,Modeling,elliptical,power,mass,galaxy,widely,used,gravitational,lensing,analyses,However,real,galaxies,complex,We,quantify,biases,due,this,mismatch,simulating,then,analyzing,mock,Hubble,Space,Telescope,imaging,lenses,distributions,inferred,from,SDSS,stellar,dynamics,data,find,accurate,recovery,morphology,except,slight,tendency,sources,be,compact,than,their,true,size,Einstein,radius,also,robustly,recovered,accuracy,global,density,slope,relative,systematic,error,compared,intrinsic,dispersion,asymmetry,leads,spurious,fitted,external,shear,strength,Furthermore,delays,modeling,without,measurements,typically,underestimated,Using,such,sub,sample,would,constant,Although,work,particular,set,specific,value,detected,may,change,another,results,strongly,suggest,next,generation,needs,models

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