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DOI: 10.1088/1475-7516/2023/04/066
¤ OpenAccess: Hybrid
This work has “Hybrid” OA status. This means it is free under an open license in a toll-access journal.

Uncovering gravitational-wave backgrounds from noises of unknown shape with LISA

Quentin Baghi,Nikolaos Karnesis,Jean-Baptiste Bayle,Marc Besançon,H. Inchauspé

Physics
Gravitational wave
Spectral density
2023
Abstract Detecting stochastic background radiation of cosmological origin is an exciting possibility for current and future gravitational-wave (GW) detectors. However, distinguishing it from other stochastic processes, such as instrumental noise and astrophysical backgrounds, is challenging. It is even more delicate for the space-based GW observatory LISA since it cannot correlate its observations with other detectors, unlike today's terrestrial network. Nonetheless, with multiple measurements across the constellation and high accuracy in the noise level, detection is still possible. In the context of GW background detection, previous studies have assumed that instrumental noise has a known, possibly parameterized, spectral shape. To make our analysis robust against imperfect knowledge of the instrumental noise, we challenge this crucial assumption and assume that the single-link interferometric noises have an arbitrary and unknown spectrum. We investigate possible ways of separating instrumental and GW contributions by using realistic LISA data simulations with time-varying arms and second-generation time-delay interferometry. By fitting a generic spline model to the interferometer noise and a power-law template to the signal, we can detect GW stochastic backgrounds up to energy density levels comparable with fixed-shape models. We also demonstrate that we can probe a region of the GW background parameter space that today's detectors cannot access.
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    Uncovering gravitational-wave backgrounds from noises of unknown shape with LISA” is a paper by Quentin Baghi Nikolaos Karnesis Jean-Baptiste Bayle Marc Besançon H. Inchauspé published in 2023. It has an Open Access status of “hybrid”. You can read and download a PDF Full Text of this paper here.