Ruling Out Dark Energy Model induced by de-Sitter Regions of Non-Singular Black Holes with Planck2018, DESI BAO, and Union3 Supernovae

TL;DR

This work assesses whether dark energy can originate from de-Sitter regions around non-singular Schwarzschild–de Sitter black holes (SdSDE) by tying the DE density to the evolving black-hole population. The authors derive ρ_DE(z) from a simulated BH mass function, implement the background SdSDE evolution into Cobaya/CAMB, and confront Planck 2018 CMB data with DESI DR2 BAO and Union3 SN. The combined data yield a significantly worse fit for SdSDE than ΛCDM (Δχ^2 ≈ 52) despite identical parameter counts, with BAO and SN data driving the tension and DESI w(a) constraints being incompatible. Consequently, the SdSDE hypothesis is strongly disfavored under current cosmological observations, though the approach demonstrates a concrete framework for testing astrophysical DE scenarios using cosmological probes.

Abstract

Dark energy(DE) remains one of the most important subjects in modern cosmology, and its physical origin is still under intensive discussion. While an astrophysical origin of DE is a highly challenging scenario, black holes stand out the most promising candidates as the astrophysical origin. In this paper, we explore a new model of DE induced by black holes, in which cosmic accelerated expansion caused by de-Sitter like space-time regions around the non-singular black holes. It is difficult to examine such a phenomena by measuring black hole mass because the energy density of the cosmological constant is much smaller than the mass density of a black hole near a black hole. On the other hand, this modification becomes dominant on the cosmological scale. Therefore, we focus on the cosmological probes and perform the MCMC analysis using Planck2018+DESI DR2+Supernovae. Since the total amount of DE density depends on the contributions of all black holes, we use the simulated results for the evolution of the number of black holes. As a result, we obtain the best-fitted total chi-squared value, $χ_\mathrm{total}^2 = 2871.13$ compared to $Λ\mathrm{CDM}$ case $χ_\mathrm{total, \, ΛCDM}^2 = 2819.00$, and $Δχ^2 \sim 50$. We conclude that this $Δχ^2$ is enough large to rule out this model, because the number of parameters is same between this model and $Λ\mathrm{CDM}$.

Figures (6)

• Figure 1: Comoving BH mass functions at redshifts $z = 0$, $1$, $2$, $4$, $6$, $8$, and $10$, using the fitting function in Eq. \ref{['schechtergaussian']} with the best-fit parameters from Table \ref{['tab_params2']}.
• Figure 2: Comoving BH mass density as a function of redshift. Red points are computed from Eq. \ref{['rho_from_massfunc']} using the mass functions in Fig. \ref{['fig:massfunc']}. The solid blue line shows the polynomial fit described by Eq. \ref{['rho_polynomial']}.
• Figure 3: Constraints on the cosmological parameters from MCMC analysis. Red and blue contours represent the SdSDE and $\Lambda$CDM models, respectively.
• Figure 4: Constraints in the $H_0$–$\Omega_\mathrm{m}$, $H_0$–$\Omega_\Lambda$, and $H_0$–$\Omega_\mathrm{c} h^2$ planes. The SdSDE model shows larger values of $H_0$, $\Omega_\Lambda$, and $\Omega_\mathrm{c} h^2$, and a smaller value of $\Omega_\mathrm{m}$ compared to the $\Lambda$CDM model.
• Figure 5: Total and component-wise $\chi^2$ values. $\chi^2_\mathrm{CMB}$, $\chi^2_\mathrm{BAO}$, and $\chi^2_\mathrm{SN}$ correspond to Planck+lensing, DESI DR2 BAO, and supernovae, respectively. The SdSDE model exhibits larger $\chi^2$ than $\Lambda$CDM.