Gravitational-wave luminosity distance in modified gravity theories

By E. Belgacem, Yves Dirian, S. Foffa, M. Maggiore. Physical Review D, 2017

142 citations recorded by the source corpus.

In modified gravity theories, the luminosity distance for gravitational waves (GWs) is in general different from that for electromagnetic signals. This opens the possibility of model-independent tests of GR, by comparing the results from standard candles with those from standard sirens. We illustrate this fact using a nonlocal modification of gravity, that has been shown to fit remarkably well CMB, SNe, BAO and structure formation data. We find that, for rather general reasons, the relative difference between the GW luminosity distance of the modified gravity model and the luminosity distance of $\Lambda$CDM is larger by one order of magnitude than the relative difference of electromagnetic luminosity distances. This effect would be missed in phenomenological studies that parametrize dark energy using only an equation of state $w_{\rm DE}(z)$. We discuss the prospects for distinguishing nonlocal gravity from $\Lambda$CDM at third-generation GW detectors such as the Einstein Telescope and we find that, depending on the exact sensitivity, a few tens of standard sirens with measured redshift at $z\sim 0.4$, or a few hundreds at $1< z < 2$, could suffice.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5027901d051f693fe21fde1d9416496fc2163b27

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Citations in the corpus

Horndeski theory and beyond: a review (2019, background): “This results in a modification of the amplitude of gravitational waves, which can be measurable [210, 211, 212].”
Science case for the Einstein telescope (2019, background): “In fact, the situation for 3G detectors is even more interesting due to a phenomenon of modified GW propagation [195, 198–203].”
Nonlocal gravity. Conceptual aspects and cosmological predictions (2017, background): “In a companion paper [94] we will elaborate on this point and discuss the possibility of using standard sirens to distinguish ΛCDM from the (minimal) RR model with third-generation GW interferometers such as the Einstein Telescope.”
Testing modified gravity at cosmological distances with LISA standard sirens (2019, background): “On top of this, it was realized in [15, 16] that, in a generic modified gravity theory, in which the deviation of d gw L (z)/d em L (z) from 1 is of the same order as the deviation of wDE(z) from −1, the effect of d gw L (z)/d em L (z) on standard sirens dominates over the effect of wDE(z).”
Dark Energy in Light of Multi-Messenger Gravitational-Wave Astronomy (2018, result): “In order to connect this result with the previously discussed theories recall that for scalar-tensor gravity ν = αM and for the non-local, RR-model ν = −2δ (Belgacem et al., 2018a).”