2025/08/21 by Meetei, Elangbam Chingkheinganba, Singh, S. Surendra · 2 citations
#Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc)
paper · doi:10.48550/arxiv.2508.15187
We investigate an interacting polytropic dark energy (PDE) model characterised by the equation of state pd = αρd^ 1+\frac1β, where the interaction between dark energy and pressureless matter is modelled via a linear coupling term Q = 3ηHρd. The background dynamics are formulated by deriving the Hubble parameter in the interacting scenario, and the model parameters are constrained through a Markov Chain Monte Carlo (MCMC) analysis using three joint observational data sets: Hubble77+BAO26, Hubble77+Pantheon+, and Hubble77+BAO26+DESI DR2. The resulting best-fit values of (H0, Ωd0, η) are (69.22+1.27-1.24, 0.73+0.02-0.02, -0.22+0.10-0.12), (69.23+1.27-1.22, 0.73+0.02-0.02, -0.34+0.15-0.17), and (67.77+1.26-1.24, 0.73+0.02-0.02, -0.02+0.10-0.11) respectively for the respective data combinations. Our results indicate a positive energy density and negative pressure over the full redshift range, with the evolution of the equation-of-state parameter and state finder parameters placing the model firmly within the Quintessence regime. The study of the deceleration parameter also reveals a shift from a decelerating to an accelerating cosmic expansion. The estimated present age of the Universe is 14 Gyr, consistent with recent observational data. Furthermore, the sign of Q implies a current energy transfer from dark energy to matter. These findings support the interacting PDE framework as a viable candidate for explaining late-time cosmic acceleration and related large-scale dynamics.