Coincidence analysis to search for inspiraling compact binaries using TAMA300 and LISM data

TL;DR

This paper describes a coincidence analysis of data from TAMA300 and LISM gravitational wave detectors, setting upper limits on inspiraling binary event rates and demonstrating a method to reduce false positives.

Contribution

It introduces a coincidence analysis method that significantly reduces false events and can be applied to multiple detectors for gravitational wave searches.

Findings

No gravitational wave signals detected.

Established an upper limit of 0.046 events/hour within 1kpc.

Method effectively reduces fake events by a factor of 10^-4.

Abstract

Japanese laser interferometric gravitational wave detectors, TAMA300 and LISM, performed a coincident observation during 2001. We perform a coincidence analysis to search for inspiraling compact binaries. The length of data used for the coincidence analysis is 275 hours when both TAMA300 and LISM detectors are operated simultaneously. TAMA300 and LISM data are analyzed by matched filtering, and candidates for gravitational wave events are obtained. If there is a true gravitational wave signal, it should appear in both data of detectors with consistent waveforms characterized by masses of stars, amplitude of the signal, the coalescence time and so on. We introduce a set of coincidence conditions of the parameters, and search for coincident events. This procedure reduces the number of fake events considerably, by a factor $\sim 10^{-4}$ compared with the number of fake events in single detector analysis. We find that the number of events after imposing the coincidence conditions is consistent with the number of accidental coincidences produced purely by noise. We thus find no evidence of gravitational wave signals. We obtain an upper limit of 0.046 /hours (CL $= 90 %$) to the Galactic event rate within 1kpc from the Earth. The method used in this paper can be applied straightforwardly to the case of coincidence observations with more than two detectors with arbitrary arm directions.