From cosmic lasagna to space-
time spaghetti – obtaining the
least-model-dependent strong
gravitational lensing probe
Abstract: Strong gravitational lensing has advanced as a standard probe to map mass
densities of cosmic structures or to try and infer parameters of the cosmological
concordance model, like the Hubble Constant. In this talk, I will introduce those
properties of a light-deflecting cosmic structure that can be uniquely and directly
determined from observables without any lens model assumptions. These properties
constitute the maximum information common to all model-based mass maps and require
less than a second of computing time. The derivation of these characteristics also
reveals the most general class of lensing degeneracies and a simple physical
interpretation of their origins. I will showcase the power of this approach in two galaxy
clusters: we can infer a least-model-dependent smoothness scale for dark matter,
reconstruct the morphology of the lensed source galaxy, and even infer global properties
of the lensing cluster in combination with complementary data. Thus, with an increasing
amount of data, this approach will allow us to gain a deeper understanding of the
necessary amount and properties of dark matter in cosmic structures.