Chi-square test on candidate events from CW signal coherent searches

In a blind search for continuous gravitational wave signals scanning a wide frequency band one looks for candidate events with significantly large values of the detection statistic. Unfortunately, a noise line in the data may also produce a moderately large detection statistic. In this paper, we describe how we can distinguish between noise line events and actual continuous wave (CW) signals, based on the shape of the detection statistic as a function of the signal’s frequency. We will analyse the case of a particular detection statistic, the F statistic, proposed by Jaranowski, Królak and Schutz. We will show that for a broad-band 10 h search, with a false dismissal rate smaller than 10−6, our method rejects about 70% of the large candidate events found in a typical data set from the second science run of the Hanford LIGO interferometer. PACS numbers: 04.80.Nn, 95.75.−z (Some figures in this article are in colour only in the electronic version)