Abstract:
The interferometric data from gravitational wave detectors is neither Gaussian nor stationary
and contains noise transients or glitches. These glitches interfere with the search algorithms
by producing high SNR triggers. In particular, for the compact coalescing binary search
which is carried out by a bank of templates, the glitches in spite of their small overlap with
the templates, because of their high amplitude, can produce detectable triggers thus giving
false alarms. Usually, the Allen chi-square test is then used to distinguish between the signal and the
glitch. In a recent paper [1], a uni ed description of all possible chi-square discriminators is given,
and also a constructive procedure is described to construct an optimal chi-square discriminator
especially if the glitch can be modeled. One such type of glitch that often occurs in the
data can be modeled as a sine-Gaussian with parameters (Q; f0). An important property
of sine-Gaussian glitch is that there is a time-lag between the trigger and the occurrence of
the glitch. Therefore the time-lag is considered separately and we construct the parameter
space using uniformly distributed points on it. The total number of points on the parameter
space is associated with the degrees of freedom (d.o.f) of the chi-square. To reduce the d.o.f, we
describe a method which uses Singular Value Decomposition that helps us to reduce and nd
the optimal number of d.o.f for the chi-square. Finally, we present a way to construct an optimal
chi-square discriminator for sine-Gaussian glitches using the procedure in the paper
