Improving the detection sensitivity of gravitational wave searches in non-stationary data

A key factor influencing detection sensitivity is ``non-stationarity" of the gravitational wave detector data, where the noise power spectral density (PSD) varies over time. Previous work has addressed the leading-order effects of PSD variation on the search background, assuming the drifts in PSD are independent of frequency bins. In this paper, we extend these methods to incorporate the frequency dependence of PSD drifts. Applying this extended method to LIGO data, we show that accounting for this frequency dependence can improve the detection volume of gravitational wave search pipelines additionally by 2%~8% depending on the false alarm rate chosen.