Gravitational-Wave Signal Simulation for LIGO

The Laser Interferometer Gravitational-wave Observatory (LIGO) has been constructed to directly measure the distortion of spacetime due to an impinging gravitational-wave (GW). LIGO’s biggest challenge is that the size of the signal is tremendously weak, and there are various kinds of noises that need to be suppressed to make the tiny signal visible. In order to assist in tackling this issue, an end-to-end time domain simulation program for LIGO (E2E) has been developed to simulate the detector response to a signal caused by a GW and to various kinds of noises under a realistic operational condition. The latter can be simulated already in the existing E2E. In order to simulate the response of LIGO to the signal of GW sources, a new software program has been developed for E2E. In this paper, the details of this software are discussed. This program calculates the time-series variation of the strain for coalescing compact binaries and spin-down supernovae. The program is flexible in choice of source and detector location and orientation and generates signals with proper correlations due to spatial separations and detector orientations. The program also visualizes the time-series of the result for one interferometer's detection or for multiple, correlated detections.