Stress testing the dark energy equation of state imprint on supernova data

• Published in: Physical review. D 2019-06, Vol.99 (12), p.1, Article 123529
• Main Authors: Moews, Ben, de Souza, Rafael S., Ishida, Emille E. O., Malz, Alex I., Heneka, Caroline, Vilalta, Ricardo, Zuntz, Joe
• Format: Article
• Language: English
• Subjects: Astronomical models; Astrophysics; Computer simulation; Cosmological constant; Cosmology; Dark energy; Divergence; Equations of state; Instrumentation and Detectors; Physics; Red shift; Sensitivity analysis; Standard model (particle physics); Supernovae
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.99.123529

This work determines the degree to which a traditional analysis of the standard model of cosmology (ΛCDM) 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 ΛCDM 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 ΛCDM model. Our results suggest that physics beyond the standard model may simply be hidden in plain sight.