Deviation from the Cosmological Constant or Systematic Errors?

TL;DR

This paper investigates the apparent deviation from a cosmological constant in dark energy's equation of state at high redshifts, considering potential systematic errors or new physics, emphasizing the need for future data.

Contribution

It provides a careful analysis of high-redshift dark energy behavior, highlighting possible systematic biases or new physics as explanations for deviations from the cosmological constant.

Findings

Deviations from -1 in dark energy EOS at z > 0.5 are significant.

Systematic errors in SNe Ia and GRB data could explain observed deviations.

Future observations are crucial to clarify dark energy nature.

Abstract

Motivated by the fact that both SNe Ia and GRBs seem to prefer a dark energy EOS greater than -1 at redshifts $z \gtrsim 0.5$, we perform a careful investigation on this situation. We find that the deviation of dark energy from the cosmological constant at redshifts $z \gtrsim 0.5$ is large enough that we should pay close attention to it with future observational data. Such a deviation may arise from some biasing systematic errors in the handling of SNe Ia and/or GRBs or more interestingly from the nature of the dark energy itself.