Testing nonstandard cosmological models with SNLS3 supernova data and other cosmological probes

TL;DR

This study evaluates various nonstandard cosmological models using SNLS3 supernova data combined with other cosmological probes, finding that model preferences depend on the data sets and constraints used.

Contribution

It compares constraints from multiple supernova samples and cosmological data sets on nonstandard models, highlighting the impact of different light-curve fitters and data combinations.

Findings

SN Ia with SALT2, SALT, or SIFTO yield consistent results.

Tensions exist between data sets and fitters for fewer-parameter models.

SNLS3 data alone favors the flat DGP model, but combined data prefers flat ΛCDM.

Abstract

We investigate the implications for some nonstandard cosmological models using data from the first three years of the Supernova Legacy Survey (SNLS3), assuming a spatially flat universe. A comparison between the constraints from the SNLS3 and those from other SN Ia samples, such as the ESSENCE, Union2, SDSS-II and Constitution samples, is given and the effects of different light-curve fitters are considered. We find that SN Ia with SALT2 or SALT or SIFTO can give consistent results and the tensions between different data sets and different light-curve fitters are obvious for fewer-free-parameters models. At the same time, we also study the constraints from the SNLS3 along with data from the cosmic microwave background and the baryonic acoustic oscillations (CMB/BAO), and the latest Hubble parameter versus redshift (H(z)). Using model selection criteria such as $\chi^2$/dof, GoF, AIC and BIC, we find that, among all the cosmological models considered here ($\Lambda$CDM, constant $w$, varying $w$, DGP, modified polytropic Cardassian, and the generalized Chaplygin gas), the flat DGP is favored by the SNLS3 alone. However, when additional CMB/BAO or H(z) constraints are included, this is no longer the case, and the flat $\Lambda$CDM becomes preferred.