Consistency between cosmological and standard siren observations in evolving dark energy
Abstract
A scalar field non-minimally coupled to gravity can be the driver of cosmic acceleration. Such a non-minimal coupling (NMC) can produce a non-zero gravitational-wave (GW) friction function αM(z), which modifies the luminosity distance inferred from GW sources relative to its electromagnetic counterpart. We use a particular NMC scalar-tensor model, that explains time-varying dark energy in good alignment with DESI, to predict αM(z) and the expected GW/EM luminosity-distance ratio DLGW/DLEM, and map it onto two common parametrizations---the cM and the (Ξ0,n) models. We find cM = −0.5± 0.2 and Ξ0 = 0.88± 0.05, n=3.2± 0.3, both consistent with GWTC-5 constraints at the ≲ 1σ level. This consistency is mostly driven by current large uncertainties in GW data, which lead to measurements consistent with both ΛCDM and the NMC model. By contrast, the dark energy constraints derived from analyzing cosmological data, under the common parametric scalar-tensor model using αM(z)=cMΩΛ(z)/ΩΛ0 and the CPL parametrized equation of state w0wa, are in 2.2σ (3.6σ) tension with the NMC predictions for the cM (w0wa) parameter. We confirm that, in order to avoid cosmological instabilities, this parametrized model imposes strong implicit priors that are incompatible with physically-motivated scalar-tensor models when dark energy is dynamical.
Related
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BibTeX
@misc{lagos2026consistency,
title = {{Consistency between cosmological and standard siren observations in evolving dark energy}},
author = {Macarena Lagos and William J. Wolf},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.04112},
eprint = {2609.04112},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.04112},
}
RIS
TY - UNPB
TI - Consistency between cosmological and standard siren observations in evolving dark energy
AU - Macarena Lagos
AU - William J. Wolf
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.04112
UR - https://arxiv.org/abs/2609.04112
AB - A scalar field non-minimally coupled to gravity can be the driver of cosmic acceleration. Such a non-minimal coupling (NMC) can produce a non-zero gravitational-wave (GW) friction function α_M(z), which modifies the luminosity distance inferred from GW sources relative to its electromagnetic counterpart. We use a particular NMC scalar-tensor model, that explains time-varying dark energy in good alignment with DESI, to predict α_M(z) and the expected GW/EM luminosity-distance ratio D_L^GW/D_L^EM, and map it onto two common parametrizations---the c_M and the (Ξ_0,n) models. We find c_M = −0.5± 0.2 and Ξ_0 = 0.88± 0.05, n=3.2± 0.3, both consistent with GWTC-5 constraints at the ≲ 1σ level. This consistency is mostly driven by current large uncertainties in GW data, which lead to measurements consistent with both ΛCDM and the NMC model. By contrast, the dark energy constraints derived from analyzing cosmological data, under the common parametric scalar-tensor model using α_M(z)=c_MΩ_Λ(z)/Ω_Λ0 and the CPL parametrized equation of state w_0w_a, are in 2.2σ (3.6σ) tension with the NMC predictions for the c_M (w_0w_a) parameter. We confirm that, in order to avoid cosmological instabilities, this parametrized model imposes strong implicit priors that are incompatible with physically-motivated scalar-tensor models when dark energy is dynamical.
ER -