Colloquium on Apr. 18th, 2019

Testing general relativity using X-ray reflection spectroscopy

Speaker: Cosimo Bambi (Fudan University)

Venue: Room 2317, SWIFAR Building

Time: 10:00 AM, Thursday, 18th April, 2019

Abstract: Einstein's theory of general relativity was proposed over 100 years ago and has successfully passed a large number of observational tests in weak gravitational fields. However, the strong field regime is still largely unexplored, and there are many modified and alternative theories that have the same predictions as Einstein's gravity for weak fields and present deviations only when gravity becomes strong. X-ray reflection spectroscopy is potentially a powerful tool for testing the strong gravity region around astrophysical black holes with electromagnetic radiation. In this talk, I will present the reflection model RELXILL_NK designed for testing the metric around black holes and the current constraints on possible new physics from the analysis of a few sources.