Torsion-Bar Antenna (TOBA) is a ground-based gravitational-wave detector for low frequency.
TOBA can detect intermediate-mass black hole binary mergers, gravitational wave stochastic background, and Newtonian noise.
TOBA is also useful for earthquake early warning.
TOBA consists of two 10-m test masses suspended horizontally and we aim to detect the torsional rotation of pendulums caused by tidal forces.
The resonant frequency of torsional motion is ,
therefore TOBA has good design sensitivity of between and .
We are currently developing the third prototype detector Phase-III TOBA with 35 cm-scale pendulums at cryogenic temperature to demonstrate noise reduction.
The target sensitivity is set to .
In this paper, we will present the principle and science of TOBA and the status of the development of Phase-III TOBA.
