Autor(es)

Lima, P. W. R. ; Lima, J. A. S. ; Jesus, J. F.

• Tipo de documento: Artigo Científico
• Fonte: EUROPEAN PHYSICAL JOURNAL C; v. 85, n. 4, p. 12-pg., 2025-04-23.

Resumo

The standard procedure to explain the accelerated expansion of the Universe is to assume the existence of an exotic component with negative pressure, generically called dark energy. Here, we propose a new accelerating flat cosmology without dark energy, driven by the negative creation pressure of a reduced relativistic gas (RRG). When the hybrid dark matter of the RRG is identified with cold dark matter, it describes the so-called CCDM cosmology whose dynamics is equivalent to the standard Lambda\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Lambda $$\end{document}CDM model at both the background and perturbative levels (linear and nonlinear). This effect is quantified by the creation parameter alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document}. However, when the pressure from the RRG slightly changes the dynamics of the universe, as measured by a parameter b, the model departs slightly from the standard Lambda\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Lambda $$\end{document}CDM cosmology. Therefore, this two-parametric model (alpha,b\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha , b$$\end{document}) describes a new scenario whose dynamics is different but close to the late-time scenarios predicted by CCDM and Lambda\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Lambda $$\end{document}CDM models. The free parameters of the RRG model with creation are constrained based on SNe Ia data (Pantheon+SH0ES) and also using H(z) from cosmic clocks. In principle, this mild distinction in comparison with both CCDM or Lambda\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Lambda $$\end{document}CDM may help alleviate some cosmological problems plaguing the current standard cosmology. (AU)

• Processo FAPESP: 11/51676-9 - Llama: um radiotelescopio para ondas mm/sub-mm nos andes, em colaboracao com a argentina.
• Beneficiário: Jacques Raymond Daniel Lépine
• Modalidade de apoio: Auxílio à Pesquisa - Temático