Leveraging time-dependent instrumental noise for the LISA stochastic gravitational wave background analysis

Variations in the instrumental noise of the Laser Interferometer Space Antenna (LISA) over time are expected as a result of, e.g., scheduled satellite operations or unscheduled glitches. We demonstrate that these fluctuations can be leveraged to improve the sensitivity to stochastic gravitational wave backgrounds (SGWBs) compared to the stationary noise scenario. This requires optimal use of data segments with downward noise fluctuations, and thus a data analysis pipeline capable of analyzing and combining shorter time segments of mission data. We propose that simulation based inference is well suited for this challenge. In an approximate, but state-of-the-art, modeling setup, we show by comparison with Fisher information matrix estimates that the optimal information gain can be achieved in practice.