http://arxiv.org/abs/1602.03883

We show that the gravitational wave source counts distribution can test how gravitational radiation propagates on cosmological scales. This test does not require obtaining redshifts for the sources. If the signal-to-noise from a gravitational wave source is proportional to the strain then it falls as $R^{-1}$, thus we expect the source counts to follow $dN/dS \propto S^{-4}$. However, if gravitational waves decay as they propagate or can propagate into other dimensions, then there can be deviations from this generic prediction. We consider the possibility that the signal-to-noise falls as $R^{-\gamma}$, where $\gamma=1$ recovers the expected predictions in a Euclidean uniformly-filled universe. We forecast the sensitivity of future observations in constraining gravitational wave physics using this method by simulating sources distributed over a finite range of signal-to-noise. We first consider the case of few objects, 7 sources, with a signal-to-noise from 8 to 24, and impose a lower limit on $\gamma$, finding $\gamma>0.33$ at 95% confidence level. The distribution of our simulated sample is very consistent with the distribution of the candidate black holes binary systems observed by Advanced LIGO. We then consider the improvement coming from further detections, simulating 100 observations spanning a wider range of signal-to-noise and measure $\gamma$ with $\sigma(\gamma)\sim 0.15$, percent level precision will be possible with 10000 objects. We generalize the formalism to account for a range of chirp masses and the possibility that the signal falls as $\exp(-R/R_0)/R^\gamma$.

Read this paper on arXiv…

E. Calabrese, N. Battaglia and D. Spergel
Fri, 12 Feb 16
7/48

Comments: Comments welcome, congratulations to the LIGO team