Probing Cosmic Acceleration by Using the SNLS3 SNIa Dataset

TL;DR

This study uses the SNLS3 supernova dataset combined with other cosmological data to investigate the nature of dark energy and cosmic acceleration, finding results consistent with a cosmological constant and no evidence for slowing acceleration.

Contribution

It provides updated constraints on dark energy parameters using the latest supernova data combined with multiple cosmological observations, confirming compatibility with the $\\Lambda$CDM model.

Findings

Results are consistent with a cosmological constant at 1σ confidence level.

No evidence found for recent slowing down of cosmic acceleration.

The $\\Lambda$CDM model remains compatible with current data.

Abstract

We probe the cosmic acceleration by using the recently released SNLS3 sample of 472 type Ia supernovae. Combining this type Ia supernovae dataset with the cosmic microwave background anisotropy data from the Wilkinson Microwave Anisotropy Probe 7-yr observations, the baryon acoustic oscillation results from the Sloan Digital Sky Survey data release 7, and the Hubble constant measurement from the Wide Field Camera 3 on the Hubble Space Telescope, we measure the dark energy equation of state $w$ and the deceleration parameter $q$ as functions of redshift by using the Chevallier-Polarski-Linder parametrization. Our result is consistent with a cosmological constant at 1$\sigma$ confidence level, without evidence for the recent slowing down of the cosmic acceleration. Furthermore, we consider three binned parametrizations ($w$ is piecewise constant in redshift $z$) based on different binning methods. The similar results are obtained, i.e., the $\Lambda$CDM model is still nicely compatible with current observations.