Math-Astro Seminar

Speaker: Marcus Werner (IPMU)
Title: Gravitational Lensing VI: "Magnification invariants and Lefschetz fixed point theory"
Date (JST): Thu, Jan 19, 2012, 10:00 - 11:30
Place: Balcony B
Abstract: Certain strong lensing models are predicted to have the property of a constant sum of image magnifications. The fact that astronomical observations often show a violation of these invariants has been an important aspect in the debate about substructure in dark matter halos. Moreover, the mathematical origin of these invariants is still not completely understood. Picking up from Akihiro's talk in December, I will summarize the relevant theory from the previous seminars in this series and show how Lefschetz fixed point theory provides insight into the geometry of some of these invariants.