Abstract
We propose a new antenna configuration of a torsion-bar antenna (TOBA) and study its performance. A TOBA is a novel type of an antenna for low-frequency gravitational waves (GWs) which consists of two bar-shaped orthogonal test masses. Previously only the rotation of the bars on the horizontal plane had been considered as an output signal. In this paper, we introduce a new antenna configuration for a TOBA to incorporate two additional outputs by measuring the rotation of the bars on the vertical planes. Such a triple-output TOBA can be regarded as a network of three coincident but misaligned interferometric detectors. The target sensitivity we consider in this paper is about at 1 Hz. Since the triple-output TOBA is sensitive to all directions of GWs, event detection rates are improved by a factor of 1.7. It also increases the parameter resolution drastically for short-duration observations because the triple-output TOBA has three independent output signals and can discriminate two polarization modes of a short-duration GW signal even with single antenna. For instance, in the case of a IMBH merger at 100 Mpc, the source location is typically measurable with an accuracy of steradians which is roughly two order of magnitude better than the conventional single-output TOBA.
- Received 4 July 2014
DOI:https://doi.org/10.1103/PhysRevD.90.064039
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