Pantheon+ constraints on dark energy and modified gravity: An evidence of dynamical dark energy

TL;DR

This study uses the latest Pantheon+ supernova data combined with other cosmological observations to constrain dark energy and modified gravity models, finding evidence for dynamical dark energy and momentum transfer in the universe.

Contribution

It provides new constraints on interacting dark energy and Hu-Sawicki f(R) gravity models using Pantheon+ data and model-independent Gaussian processes, revealing potential dynamical dark energy.

Findings

Weak constraints from Pantheon+ alone.

Strong combined constraints indicating momentum transfer in dark sector.

Evidence of dynamical dark energy beyond 2σ confidence level.

Abstract

We use the latest Type Ia supernovae sample Pantheon+ to explore new physics on cosmic scales. Specifically, in light of this new sample, we constrain the interacting dark energy and Hu-Sawicki $f(R)$ gravity models and employ the model-independent Gaussian processes to investigate whether there is an evidence of dark energy evolution. We find that Pantheon+ alone just gives weak constraints. However, a data combination of Pantheon+ with cosmic microwave background, baryon acoustic oscillations and cosmic chronometers gives a strong constraint on the modified matter expansion rate $\epsilon=0.048\pm0.026$, which indicates that the momentum may transfer from dark energy to dark matter in the dark sector of the universe at the $1.85\,\sigma$ confidence level. In the meantime, we obtain a very tight constraint on the deviation from general relativity $\log_{10} f_{R0}< -6.32$ at the $2\,\sigma$ confidence level. Interestingly, when combining Pantheon+ with cosmic chronometers and cosmic microwave background data, we find a quintessence-like dark energy signal beyond the $2\,\sigma$ confidence level in the redshift range $z\in[0.70,1.05]$. This implies the nature of dark energy may actually be dynamical.