Sixteenth Marcel Grossmann Meeting

The Tale of H0 Crisis and the Gravitational Transition

8 Jul 2021, 18:11

19m

Talk in the parallel session Status of the H_0 and sigma_8 tensions: theoretical models and model-independent constraints Status of the H_0 and Sigma_8 Tensions: Theoretical Models and Model-Independent Constraints

Speaker

George Alestas (University of Ioannina)

Description

We propose a late time gravitational transition at low redshifts $z_t<0.1$ as a possible solution of both the Hubble and growth tensions. Such a transition would naturally lead to a transition of the intrinsic SnIa luminosity and absolute magnitude $M$ at $z_t$ and could also be accompanied by a transition in the dark energy equation of state parameter $w$. Thus we would have a late $w-M$ phantom transition ($LwMPT$). Such a model does not belong to the category of dark energy models with late time smooth deformations of the Hubble expansion rate $H(z)$, that as we have shown fail to address the growth tension. Therefore, the $LwMPT$ model has the potential of resolving the growth tension by reducing the growth of density perturbations without affecting the Planck/$\mathrm{\Lambda }$CDM background expansion. Finally, we offer observational hints for a gravitational transition that would support the $LwMPT$ hypothesis via the study of the evolution of the baryonic Tully-Fisher relation. Specifically, we use a recently published data compilation, finding hints at $\approx 3\sigma$ level for a transition at critical distances $D_c\simeq 9Mpc$ and $D_c\simeq 17Mpc$.

Presentation materials

G_Alestas_MG16.pdf