This work determines the degree to which a traditional analysis of the standard model of cosmology ($\mathrm{\Lambda }\mathrm{CDM}$) based on type Ia supernovae can identify deviations from a cosmological constant in the form of a redshift-dependent dark energy equation of state $w(z)$. We introduce and apply a novel random curve generator to simulate instances of $w(z)$ from constraint families with increasing distinction from a cosmological constant. After producing a series of mock catalogs of binned type Ia supernovae corresponding to each $w(z)$ curve, we perform a standard $\mathrm{\Lambda }\mathrm{CDM}$ analysis to estimate the corresponding posterior densities of the absolute magnitude of type Ia supernovae, the present-day matter density, and the equation of state parameter. Using the Kullback-Leibler divergence between posterior densities as a difference measure, we demonstrate that a standard type Ia supernova cosmology analysis has limited sensitivity to extensive redshift dependencies of the dark energy equation of state. In addition, we report that larger redshift-dependent departures from a cosmological constant do not necessarily manifest easier-detectable incompatibilities with the $\mathrm{\Lambda }\mathrm{CDM}$ model. Our results suggest that physics beyond the standard model may simply be hidden in plain sight.

• Received 23 December 2018

DOI:https://doi.org/10.1103/PhysRevD.99.123529