$\nu$Galileon: modified gravity with massive neutrinos as a testable alternative to $\Lambda$CDM

Abstract

We show that, in the presence of massive neutrinos, the Galileon gravity model provides a very good fit to the current CMB temperature, CMB lensing and BAO data. This model, which we dub $\nu \mathrm{Galileon}$, when assuming its stable attractor background solution, contains the same set of free parameters as $\Lambda \mathrm{CDM}$, although it leads to different expansion dynamics and nontrivial gravitational interactions. The data provide compelling evidence ($\gtrsim 6\sigma$) for nonzero neutrino masses, with $\Sigma m_{\nu }\gtrsim 0.4\mathrm{eV}$ at the $2\sigma$ level. Upcoming precision terrestrial measurements of the absolute neutrino mass scale therefore have the potential to test this model. We show that CMB lensing measurements at multipoles $l\lesssim 40$ will be able to discriminate between the $\nu \mathrm{Galileon}$ and $\Lambda \mathrm{CDM}$ models. Unlike $\Lambda \mathrm{CDM}$, the $\nu \mathrm{Galileon}$ model is consistent with local determinations of the Hubble parameter. The presence of massive neutrinos lowers the value of ${\sigma }_8$ substantially, despite of the enhanced gravitational strength on large scales. Unlike $\Lambda \mathrm{CDM}$, the $\nu \mathrm{Galileon}$ model predicts a negative ISW effect, which is difficult to reconcile with current observational limits.

4 pages, 2 figures, 1 table. Version 3: matches published version

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Cited by in corpus (8)

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• Cosmology-marginalized approaches in Bayesian model comparison: the neutrino mass as a case study
• Observational Constraints in Nonlocal Gravity: the Deser-Woodard Case
• Linear perturbations in K-mouflage cosmologies with massive neutrinos