Model selection with the Pantheon+ Type Ia supernova sample

Context. Recent discoveries, for example by JWST and DESI, have elevated the level of tension with inflationary Λ cold dark matter (ΛCDM). For example, the empirical evidence now suggests that the standard model violates at least one of the energy conditions from general relativity, which were designed to ensure that systems have positive energy, attractive gravity, and non-superluminal energy flows. Aims. We used a recently compiled Type Ia supernova sample to examine whether ΛCDM violates the energy conditions in the local Universe, and carried out model selection with its principal competitor, the R h = ct universe. Methods. We derived model-independent constraints on the distance modulus based on the energy conditions and compared them with the Hubble diagram predicted by both ΛCDM and R h = ct , using the Pantheon+ Type Ia supernova catalogue. Results. We find that ΛCDM violates the strong energy condition over the redshift range z ⊂ (0, 2), whereas R h = ct satisfies all four energy constraints. At the same time, R h = ct is favoured by these data over ΛCDM with a likelihood of ∼89.8% versus ∼10.2%. Conclusions. The R h = ct model without inflation is strongly favoured by the Type Ia supernova data over the current standard model, while simultaneously adhering to the general relativistic energy conditions at both high and low redshifts.