Most of my work has to do with dark matter: measuring the amount, and, more importantly, its spatial distribution on a wide range of astrophysical scales, from sub-galactic to super-cluster. Detailed knowledge of dark matter distribution will enable us to place constraints on the physical properties of dark matter particles. Since dark matter is invisible, mapping out its distribution must rely on indirect methods. While a few mass reconstruction methods exist, gravitational lensing is the optimal one, as it does not rely on any assumptions about the physical state of the dark matter or the light emitting matter. Another interesting aspect of dark matter is the study of its dynamics in galaxies and clusters of galaxies. In the last decade we have learned much about the properties of relaxed dark matter halos from numerical computer simulations, however, understanding the physics behind these results is still an open issue. This is the other major direction of my research.
In Lens Models Under the Microscope: Comparison of Hubble Frontier Field Cluster Magnification Maps
(Priewe et al. 2017) we showed that the uncertainties quoted by most cluster-lens reconstruction methods often do not overlap (blue sets of 2 lines are 1-sigma errors). Gray thick lines are uncertainties from our free-form Grale reconstructions. The horizontal axis presents many locations in the lens plane; the points have been arranged in increasing order of median magnification. The left and right panels above show two Hubble Frontier Cluster Lenses Abell 2744 and MACSJ 0416.
