Speaker
Description
In light of the evidence for dynamical dark energy (DE) found from the Dark Energy
Spectroscopic Instrument (DESI) baryon acoustic oscillation (BAO) measurements, we perform
a non-parametric, model-independent reconstruction of the DE density evolution. To do so, we
develop and validate a new framework that reconstructs the DE density through a third-degree
piece-wise polynomial interpolation, allowing for direct constraints on its redshift evolution without
assuming any specific functional form. The strength of our approach resides in the choice of directly
reconstructing the DE density, which provides a more straightforward relation to the distances
measured by BAO than the equation of state parameter. We investigate the constraining power
of cosmic microwave background (CMB) observations combined with supernovae (SNe) and BAO
measurements. In agreement with results from other works, we find a preference for deviations
from ΛCDM, with a significance of 2.4σ when using the Dark Energy Survey Year 5 (DESY5) SNe
data, and 1.3σ with PantheonPlus. The pipeline developed in the work I present is ready to be used with future high-precision data to further investigate the evidence for a non-standard background evolution.
