We consider a wide range of parametric mass models for B 1933+503 , a ten-image radio lens , and identify shared properties of the models with the best fits .
The approximate rotation curves varies by less than 8.5 % from the average value between the innermost and the outermost image ( 1.5 h ^ { -1 } kpc to 4.1 h ^ { -1 } kpc ) for models within 1 \sigma of the best fit , and the radial dependence of the shear strength and angle also have common behavior for the best models .
The time delay between images 1 and 6 , the longest delay between the radio cores , is \Delta t = ( 10.6 ^ { +2.4 } _ { -1.1 } ) h ^ { -1 } days ( \Omega _ { 0 } = 0.3 , \lambda _ { 0 } = 0.7 ) including all the modeling uncertainties .
Deeper infrared observations , to more precisely register the lens galaxy with the radio images and to measure the properties of the Einstein ring image of the radio source ’ s host galaxy , would significantly improve the model constraints and further reduce the uncertainties in the mass distribution and time delay .