Noise angular power spectrum of gravitational wave background experiments

Abstract

We construct a model for the angular power spectrum of the instrumental noise in interferometer networks mapping gravitational wave backgrounds (GWBs) as a function of detector noise properties, network configuration, and scan strategy. We use the model to calculate the noise power spectrum for current and future ground-based experiments, as well as for planned space missions. We present our results in a language similar to that used in cosmic microwave background and intensity mapping experiments, and connect the formalism with the sensitivity curves that are common lore in GWB analyses.

Stochastic gravitational-wave background as a tool to investigate multi-channel astrophysical and primordial black-hole mergers

“…For triangular detectors we take into account the fact that the three nested inteferometers have correlated noise. All PI sensitivity curves are computed using the public code schNell (Alonso et al 2020). We choose a (optimistic) SNR threshold of ρ = 2 to claim a detection, as commonly done in the literature on the subject (see e.g., Périgois et al 2021).…”

“…A level of correlation of 20% is therefore quite conservative. As the site for ET has not yet been chosen, we arbitrarily choose a location in Sardinia, close to one of the surveyed sites (see Alonso et al (2020) for the specific coordinates and orientation angle of the triangular network). We use the sensitivity curve of the instrument in the so-called D-configuration (Hild et al 2011).…”

“…These functions are already defined in schNell (Alonso et al 2020) for different detector classes. We define the average antenna patter function, often referred to in the literature as average overlap function (i.e.…”

The Gravitational-wave physics II: Progress

“…Instead of the energy spectrum of GWs from topological defects, we also find the anisotropies of those stochastic GW backgrounds carry unique information about inflation. The anisotropies in stochastic GW backgrounds could be generated by the sources [196,[207][208][209] and the processes during propagation [210][211][212][213], which in most cases are still challenging to observe [214][215][216][217][218][219]. We explore the SGWB produced from unstable cosmic domain walls, which annihilates before dominating the Universe [220,221].…”

Cross-correlating Astrophysical and Cosmological Gravitational Wave Backgrounds with the Cosmic Microwave Background

“…In our analysis we have neglected the instrumental noise of CMB experiment, since it is well known that at the multipoles we are interested in ( 100), available CMB data are completely cosmic variance dominated. On the interferometer side, we have instead considered the expected noise levels of LISA and BBO, following [24,56]; for BBO, we have only considered the two units of aligned detectors in the star-of-David [57,58]. The corresponding noise angular power-spectra are plotted in Figure 6 in Appendix B.…”