PROBING STRONG GRAVITY WITH FAST X-RAY TIMING: FROM THE ROSSI X-RAY TIMING EXPLORER TO XEUS

摘要

With its ability to look at bright galactic X-ray sources with sub-millisecond time resolution, the Rossi X-ray Timing Explorer (RXTE) discovered that the X-ray emission from accreting compact stars shows quasi-periodic oscillations on the dynamical timescales of the strong field region. This breakthrough suddenly opened up a new window on fundamental physics, by providing new insights on strong gravity. Building upon the RXTE legacy, along the Cosmic Vision exercise, testing General Relativity in the strong field limit was recognized recently as a key goal to be pursued in the ESA science program for the years 2015- 2025. This in turn identified the need for a large (10 m{sup}2 class) aperture X-ray observatory. In parallel, the XEUS mission concept has also evolved into a single launch L2 formation flying mission, with a focal plane instrumentation that includes a fast timing instrument. In this paper I will outline the strong gravity science that will be addressed with fast X-ray timing on XEUS.