Gravitational wave detection in space—a new window in astronomy

Abstract

The article is divided into two parts. Part one aims to explain the physical concept of gravitational waves in terms of the Weyl curvature of a spacetime and present a basic theoretical framework to describe detection of gravitational waves on ground as well as in space. In part two, based on two phases of feasibility study commissioned by the Chinese Academy of Sciences and under the auspices of the Pioneer Explorer (Xiandao) Program, we further elaborate on the astrophysical significance of detection of gravitational wave in space, especially as a new window to probe and address certain key problems in astronomy and cosmology, such as stellar evolution, galaxy formation in the early Universe, co-evolution of black holes and galaxies, etc. The mission design of the Taiji mission put forward by the Chinese Academy of Sciences is then outlined. The primary science driver of the mission as well as the differences with the (e)LISA mission are further explained. A preliminary analysis of the key payloads of the Taiji mission is also given.