Some remarks on the observational constraints on the self-interacting scalar field model for dark energy

TL;DR

This paper investigates a self-interacting scalar field model for dark energy, allowing null energy condition violations and phantom behavior, tested against supernova and matter power spectrum data, revealing degeneracies and preferences for phantom-like states.

Contribution

It introduces observational constraints on a scalar field dark energy model that permits phantom behavior and null energy condition violations, analyzing supernova and matter power spectrum data.

Findings

Supernova data favor phantom-like configurations.

Matter power spectrum constraints are highly degenerate.

Phantom equation of state parameters are widely admitted without priors.

Abstract

The dark energy component of the cosmic budget is represented by a self-interacting scalar field. The violation of the null energy condition is allowed. Hence, such component can also represent a phantom fluid. The model is tested using supernova type Ia and matter power spectrum data. The supernova test leads to preferred values for configurations representing the phantom fluid. The matter power spectrum constraints for the dark energy equation of state parameter are highly degenerated. In both cases, values for the equation of state parameter corresponding to the phantom fluid are highly admitted if no particular prior is used.