摘要
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-Ma NGA 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 strengthγext=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 H0 by~9%.Although this work is based on a particular set of Ma NGA 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.
基金
the support of the National Natural Science Foundation of China(Nos.11988101,11773032,12022306)
the science research grants from the China Manned Space Project(Nos.CMS-CSST-2021-B01,CMS-CSST-2021-A01)
the support from K.C.Wong Education Foundation
funding from the UK Space Agency through award ST/W002612/1
from STFC through award ST/T002565/1
support by the European Research Council(ERC)through Advanced Investigator grant to CSF,DMIDAS(GA 786910)
supported by the European Research Council Horizon 2020 grant“EWC”(award AMD-776247-6)
supported by an STFC/UKRI Ernest Rutherford Fellowship,Project Reference:ST/S004998/1。
