A lensed radio jet at milli-arcsecond resolution I: Bayesian comparison of parametric lens models

Understand

We investigate the mass structure of a strong gravitational lens galaxy at $z=0.350$, taking advantage of the milli-arcsecond (mas) angular resolution of very long baseline interferometric (VLBI) observations.

• In the first analysis of its kind at this resolution, we jointly infer the lens model parameters and pixellated radio source surface brightness.
• We consider several lens models of increasing complexity, starting from an elliptical power-law density profile.
• We extend this model to include angular multipole structures, a separate stellar mass component, additional nearby field galaxies, and/or a generic external potential.