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arXiv · 2011.05055

Spectral separation of the stochastic gravitational-wave background for LISA: observing both cosmological and astrophysical backgrounds

Guillaume Boileau·Nelson Christensen·Renate Meyer·Neil J. Cornish
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Abstract

With the goal of attempting to observe a stochastic gravitational wave background (SGWB) with LISA, the spectral separability of the cosmological and astrophysical backgrounds is important to estimate. We attempt to determine the level with which a cosmological background can be observed given the predicted astrophysical background level. We predict detectable limits for the future LISA measurement of the SGWB. Adaptive Markov chain Monte-Carlo methods are used to produce estimates with the simulated data from the LISA Data challenge (LDC). We also calculate the Cramer-Rao lower bound on the variance of the SGWB parameter uncertainties based on the inverse Fisher Information using the Whittle Likelihood. The estimation of the parameters is done with the 3 LISA channels $A$, $E$, and $T$. We simultaneously estimate the noise using a LISA noise model. Assuming the expected astrophysical background, a cosmological background energy density of around $\Omega_{GW,Cosmo} \approx 1 \times 10^{-12}$ to $1 \times 10^{-13}$ can be detected by LISA.

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Guillaume Boileau, Nelson Christensen, Renate Meyer, Neil J. Cornish. 2020-11-10. Spectral separation of the stochastic gravitational-wave background for LISA: observing both cosmological and astrophysical backgrounds. https://doi.org/10.1103/physrevd.103.103529

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