Modelling ALMA observations of strong gravitational lenses detected by Herschel

We have modelled ALMA imaging of six strong gravitationally lensed galaxies detected by the Herschel Space Observatory. Both the cleaned image plane data and the directly observed interferometric visibilities have been modelled, enabling comparison of both approaches. In the majority of cases, the recovered lens models are consistent between modelling methods, although a few systems show some small differences, particularly those with more poorly resolved Einstein rings. Our modelling recovers mass properties of the lensing galaxies and, by determining magnification factors, intrinsic properties of the lensed sub-millimetre sources. The mass density profiles of all six lenses are close to isothermal. We find that the lensed sources all have high ratios of star formation rate to dust mass, consistent with or higher than the mean ratio for high redshift sub-millimetre galaxies and low redshift ultra-luminous infra-red galaxies. Most reconstructed sources show disturbed morphologies.