# Gravitational wave source counts at high redshift and in models with extra dimensions [CEA]

Gravitational wave (GW) source counts have been recently shown to be able to test how gravitational radiation propagates with the distance from the source. Here, we extend this formalism to cosmological scales, i.e. the high redshift regime, and we also allow for models with large or compactified extra dimensions like in the Kaluza-Klein (KK) model. We found that in the high redshift regime one would potentially expect two windows where observations above the minimum signal-to-noise threshold can be made, assuming there are no higher order corrections in the redshift dependence of the signal-to-noise $S/N(z)$ for the expected prediction. Furthermore, we also considered the case of intermediate redshifts, i.e. $0<z\lesssim1$, where we show it is possible to find an analytical approximation for the source counts $\frac{dN}{S/N}$ in terms of the cosmological parameters, like the matter density $\Omega_{m,0}$ in the cosmological constant model and also the cosmographic parameters $(q_0,j_0,s_0)$ for a general dark energy mode. We then forecast the sensitivity of future observations in constraining GW physics but also the underlying cosmology by simulating sources distributed over a finite range of signal-to-noise with a number of sources ranging from 10 to as many as 500 sources as expected from future detectors. We find that with 500 events it will be possible to provide constraints on $\Omega_{m,0}$ on the order of a few percent and with the precision growing fast with the number of events. In the case of extra dimensions we find that depending on the degeneracies of the model, with 500 events it maybe possible to provide stringent limits on the existence of the extra dimensions if the aforementioned degeneracies can be broken.

J. Garcia-Bellido, S. Nesseris and M. Trashorras
Fri, 18 Mar 16
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