Detecting Features in the Dark Energy Equation of State: A Wavelet Approach

Abstract

We study the utility of wavelets for detecting the redshift evolution of the dark energy equation of state w(z) from the combination of supernovae, CMB and BAO data. We show that local features in w, such as bumps, can be detected efficiently using wavelets. To demonstrate, we first generate a mock supernovae (SNe) data sample for a SNAP-like survey with a bump feature in w(z) hidden in, then successfully discover it by performing a blind wavelet analysis. We also apply our method to analyze the recently released "Constitution" SNe data, combined with WMAP and BAO from SDSS, and find weak hints of dark energy dynamics. Namely, we find that models with w(z) < -1 for 0.2 < z < 0.5, and w(z)> -1 for 0.5 < z <1, are mildly favored at 95% confidence level. This is in good agreement with several recent studies using other methods, such as redshift binning with principal component analysis (PCA) (e.g. Zhao and Zhang, arXiv:0908.1568)

8 pages, 6 figures. Minor changes from v1, matches the version published in JCAP.

Cited by in corpus (16)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Nonparametric Dark Energy Reconstruction from Supernova Data
• Nonparametric Reconstruction of the Dark Energy Equation of State
• Omnipotent dark energy: A phenomenological answer to the Hubble tension
• A New Equation of State for Dark Energy Model
• Metric $f(R)$ gravity with dynamical dark energy as a scenario for the Hubble tension
• Inevitable manifestation of wiggles in the expansion of the late Universe
• Will the tachyonic Universe survive the Big Brake?
• Probing the dynamical behavior of dark energy
• Principal components of dark energy with SNLS supernovae: the effects of systematic errors
• The complementarity of the redshift drift
• Figure of Merit and Different Combinations of Observational Data Sets
• Direct reconstruction of dynamical dark energy from observational Hubble parameter data
• Freezing Out Early Dark Energy
• Dark Energy in the DESI Era: A Brief Review of Evidence, Beyond-$\Lambda$CDM Interpretations, and Tensions
• Analysis of recent type Ia supernova data based on evolving dark energy models