http://arxiv.org/abs/2101.08641
A dark-energy which behaves as the cosmological constant until a sudden phantom transition at very-low redshift ($z<0.1$) seems to solve the >4$\sigma$ disagreement between the local and high-redshift determinations of the Hubble constant, while maintaining the phenomenological success of the $\Lambda$CDM model with respect to the other observables. Here, we show that such a hockey-stick dark energy cannot solve the $H_0$ crisis. The basic reason is that the supernova absolute magnitude $M_B$ that is used to derive the local $H_0$ constraint is not compatible with the $M_B$ that is necessary to fit supernova, BAO and CMB data, and this disagreement is not solved by a sudden phantom transition at very-low redshift. Finally, we encourage the community to adopt in the statistical analyses the prior on the supernova absolute magnitude $M_B$ as an alternative to the prior on $H_0$. The three reasons are: i) one avoids double counting of low-redshift supernovae, ii) one avoids fixing the deceleration parameter to the standard model value $q_0=-0.55$, iii) one includes in the analysis the fact that $M_B$ is constrained by local calibration, an information which would otherwise be neglected in the analysis, biasing both model selection and parameter constraints.
D. Camarena and V. Marra
Fri, 22 Jan 21
59/69
Comments: 7 pages, 5 figures, 1 tables. CalPriorSNIa is available at this http URL