Events trigger generator for resonant spherical detectors of gravitational waves

TL;DR

This paper presents a data processing pipeline for a spherical gravitational wave detector, combining multiple analysis methods to improve event detection accuracy and reduce false alarms, with validation through simulation of the miniGRAIL detector.

Contribution

The paper introduces a novel pipeline that converts detector outputs into spherical modes, uses combined algorithms for event detection and direction reconstruction, and demonstrates effectiveness through simulations.

Findings

Effective reduction of false event detections to less than 10%

Successful simulation of miniGRAIL detector operation at planned sensitivity

Combined geometrical and probabilistic methods enhance detection reliability

Abstract

We have set up and tested a pipeline for processing the data from a spherical gravitational wave detector with six transducers. The algorithm exploits the multichannel capability of the system and provides a list of candidate events with their arrival direction. The analysis starts with the conversion of the six detector outputs into the scalar and the five quadrupolar modes of the sphere, which are proportional to the corresponding gravitational wave spherical components. Event triggers are then generated by an adaptation of the WaveBurst algorithm. Event validation and direction reconstruction are made by cross-checking two methods of different inspiration: geometrical (lowest eigenvalue) and probabilistic (maximum likelihood). The combination of the two methods is able to keep substantially unaltered the efficiency and can reduce drastically the detections of fake events (to less than ten per cent). We show a quantitative test of these ideas by simulating the operation of the resonant spherical detector miniGRAIL, whose planned sensitivity in its frequency band (few hundred Hertz's around 3 kHz) is comparable with the present LIGO one.