Astro Seminar Series - VIA ZOOM

Kazuya Koyama is a Professor of Cosmology at the University of Portsmouth.  His research interests lie in theoretical cosmology, particularly the origin of structure in our Universe and the late time acceleration of the Universe. He was awarded his PhD from Kyoto University. Prof. Koyama's research is supported by the UK Science and Technology Facilities Council and the European Research Council’s consolidator grant “Cosmological Tests of Gravity”.

Talk Title and Abstract:

General relativistic weak-field limit and Newtonian N-body simulations

Future galaxy surveys such as Euclid, LSST and SKA will cover larger and larger scales where general relativistic effects become important. On the other hand, our study of large scale structure still relies on Newtonian N-body simulations. I show how standard Newtonian N-body simulations can be interpreted in terms of the weak-field limit of general relativity. Our framework allows the inclusion of radiation perturbations and the non-linear evolution of matter. I show how to construct the weak-field metric by combining Newtonian simulations with results from Einstein-Boltzmann codes. I discuss observational effects on weak lensing and ray tracing, identifying important relativistic corrections. Finally, I show that this framework can be extended to gravitational theories beyond general relativity.

Would you like to join this Zoom seminar?  Please email Donna Hayes.