Abstract
In the past two decades, smooth lens models constructed for multiply-lensed quasar systems have been known not to be able to reproduce the brightnesses of the quasar images – known as flux-ratio anomalies. Studies have been using these anomalous systems to search for signals of Dark Matter substructures. However, to what extent are these lensing anomalies truly generated by substructures rather than inaccuracies in smooth lens models? Addressing this question is essential for differentiating the type and abundance of the DM substructures around massive galaxies. To address this question, we have created mock multiply-lensed quasar images lensed by simulated galaxies (substructures removed) extracted from the TNG50 simulation. From these images, we construct smooth lens models using the same approach as for real multiply-lensed quasars. In this way, we can assess the levels of lensing anomalies left by inaccuracies in smooth lens models for the simulated galaxies, providing an instructive comparison with lensing anomalies left by smooth lens models for real multiply-lensed quasars. Our early results show that smooth lens models failing in capturing the angular complexities of the mass profile of the lensing galaxies give rise to appreciable lensing anomalies. For a lens image, such incapacity of smooth lens models yields a position anomaly of ~4.2—21.5 mas and a magnification anomaly of ~0.6—10.7. We present the results from our work thus far and look ahead to further explore the level of lensing anomalies left by DM substructures around lensing galaxies.
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