Numerical relativity and gravitational wave astronomy

Abstract

The first direct detection of gravitational wave has been realized by LIGO 100 years after Einstein’s theoretical prediction. It opens a new window for human to observe our Universe and initiates the age of Gravitational Wave Astronomy. The data analysis of gravitational wave detection is a typically signal extraction problem and the matched filtering technique has shown to be an optimal method in extracting weak signal buried in strong Gaussian noises. Matched filtering requires the accurate gravitational waveforms. It is also essential for the parameter estimation of the gravitational wave source, with which the GW150914 was recognized as a binary of 29 and 36 solar masses black holes merging about 1.3 billion light years away. Nowadays, other laser interferometric gravitational wave detectors such as Virgo, KAGRA and the third LIGO in the India, IndIGO, are under construction. The space-borne detection projects including eLISA, Taiji and TianQin are also in progress. The pulsar timing approach with FAST, SKA and other radio telescope arrays to detect gravitational wave are also in the rapid development. It is foreseeable the gravitational wave astronomy in the wide frequency band from 10–10 to 1000 Hz will be realized in the near future. As such, the matched filtering plays an important role, and correspondingly the theoretical research of gravitational wave source models becomes urgent and important. For astrophysical realistic objects without symmetries in general, the analytical treatment of Einstein equation becomes nearly intractable. The numerical relativity then becomes an essential method and tool for solving the Einstein equation. We briefly introduce the state of art research of numerical relativity in the viewpoint of gravitational wave astronomy.