Strong gravitational lensing is one of the most accurate methods to measure the mass of galaxies and haloes and one of the most promising to investigate the nature of dark matter. It allows us to probe one of the key signatures of warm dark matter models: the lack of small-mass dark clumps with respect to CDM. Low-mass haloes and subhaloes can be detected through their effect on the surface...
The cold dark matter (CDM) paradigm makes a prediction of ubiquitous clumps of DM with masses <10^9Msun, which do not form in alternative models of warm or self-interacting DM. Using galaxy-scale strong gravitational lenses, the presence (or lack thereof) of these DM clumps can be inferred by looking for distortions in the lensed source’s emission. I present results scanning for DM clumps in...
large scale structure numerical simulations do not have the resolution to accurately describe all the structure on small scale relevant for strong gravitational lensing. I describe recent progress in combining N-body simulations describing the large scale structure with semi-analytical enhanced structure ray-tracing bridging the gap between week and strong lensing.
I will present a few original aspects of the small scale properties of the lensing deflection field that arise from the full multiple plane ray-tracing.
Constraining the distribution of small-scale structure in our universe allows us to probe alternatives to the cold dark matter paradigm. Strong gravitational lensing offers a unique window into small dark matter halos ($<10^{10} M_\odot$) because these halos impart a gravitational lensing signal even if they do not host luminous galaxies. We create large datasets of strong lensing images with...
I will discuss the theoretical modelling of line-of-sight perturbations in strong gravitational lensing. Two points will be highlighted:
1. There exists a notion of line-of-sight shear that is, in principle, distinguishable from properties of the main lens.
2. Distortions beyond convergence and shear (flexion, etc.) could play an important role.
