Least model-dependent strong lensing properties of galaxy clusters

Strong gravitational lenses are massive cosmic objects, like galaxies or galaxy clusters, which can map an extended background source, like a galaxy, into several highly distorted and magnified images. Analysing the properties of those images yields important information about the distribution of the deflecting mass and the background source. Common approaches to reconstruct the source or the deflecting mass distribution model the global properties of the source and the lens. They obtain a consistent description of the entire configuration by refining the model until it matches the observation to a predefined precision. In contrast, this talk shows a different approach to infer local properties of the gravitational lens and to reconstruct the source only using the properties of the multiple images without assuming a lens or a source model. The approach can be applied to galaxy or galaxy-cluster lenses in the same way and yields the maximum information all lens models agree upon. Showcasing two example lenses, I highlight 1) how to obtain a smoothness scale for dark matter with it from only three multiple images in a newly discovered cluster and 2) how to identify and resolve limits of lens models that may lead to highly unrealistic dark matter properties. References: - Lens method overview: https://arxiv.org/abs/1906.05285 - Examples: https://arxiv.org/abs/2207.01630 and https://arxiv.org/abs/2306.11779 More information about me: Dr. Jenny Wagner Bahamas Advanced Study Institute & Conferences https://thegravitygrinch.blogspot.com https://en.wikipedia.org/wiki/Jenny_Wagner Strong electromagnetic and gravitational field physics: From laboratories to early Universe / 379 Pair Production in Charged Black Holes: Monodromy Approach National Central University, Taiwan In this talk I will firstly review the Schwinger effect in charged black holes and then introduce a remarkable alternative approach by using the monodromy. The explicit elaboration of monodromy and the model calculations seem to reveal evidences that the monodromy can provide a practical technique to study the spontaneous pair production in general black holes and electromagnetic fields.