Observational constraints on Barrow holographic dark energy coupled with a non-cold dark matter component from DESI DR2

Abstract

We investigate the cosmological viability of Barrow holographic dark energy in a spatially flat Friedmann--Lema\^ıtre--Robertson--Walker universe in which the dark matter component is allowed to have a non-zero pressure, characterized by a constant equation-of-state parameter $w_{m}$. By considering the future event horizon as the infrared cutoff, we derive the master equation, which describes the cosmological dynamics for the background space. We constrain the model against late-time data, combining the baryon acoustic oscillation from DESI DR2 with three different catalogues for the Type Ia Supernova measurements and the Cosmic Chronometers. The dark matter equation of state is constrained to $w_{m}=0.033_{-0.030}^{+0.045}$, $0.009_{-0.041}^{+0.047}$, and $0.033_{-0.029}^{+0.042}$, for the PantheonPlus, the Union3.0 and the DES-Dovekie supernova datasets respectively. Therefore, the pressureless limit is recovered within the $2σ$ regime. On the other hand, the Barrow exponent is weakly constrained, due to the $Δ-w_{m}$ degeneracy. The dark energy equation of state remains above the phantom divide throughout the redshift range probed. Finally, in the comparison of the statistical parameters with that of $Λ$CDM, it follows $Δ\mathrm{AIC}=+2.23$, $+0.75$, and $+1.38$, $\ $while for the Bayesian evidence we find $Δ\ln Z=-0.63$, $+0.47$, and $-0.13$, which suggest that the datasets considered in this analysis do not have a preferred model. Finally the relation with the corresponding Tsalis holographic dark energy model is discussed.