Isotropic vs. Anisotropic components of BAO data: a tool for model selection

Understand

We conduct a selective analysis of the isotropic ($D_V$) and anisotropic ($AP$) components of the most recent Baryon Acoustic Oscillations (BAO) data.

• We find that these components provide significantly different constraints and could provide strong diagnostics for model selection, also in view of more precise data to arrive.
• For instance, in the $\Lambda$CDM model, we find a mild tension of $\sim 2 \sigma$ for the $\Omega_m$ estimates obtained using $D_V$ and $AP$ separately.
• Considering both $\Omega_k$ and $w$ as free parameters, we find that the concordance model is in tension with the best-fit values provided by the BAO data alone at 2.2$\sigma$.