Is $ω_0 ω_a$CDM a good model for the clumpy Universe?
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arXiv
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| Auteurs principaux: | , , , |
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866908429438681088 |
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| author | Oliveira, Fernanda Avila, Felipe Franco, Camila Bernui, Armando |
| author_facet | Oliveira, Fernanda Avila, Felipe Franco, Camila Bernui, Armando |
| contents | The DESI collaboration just obtained a set of precise BAO measurements, that combined with CMB and SNIa datasets show that the $ω_0 ω_a$CDM model is preferred over $Λ$CDM, at more than $4\,σ$, to describe the dynamics of the expanding Universe. This raises the question whether this model also suitably describes the clumpy Universe. Also lately, detailed analyses of diverse cosmic tracers resulted in a new dataset of measurements of an observable from the clumpy Universe: $σ_8(z)$, spanning a high-redshift data $z \in [0.013, 3.8]$. In this work we use this dataset of 15 $σ_8(z_i)$ measurements to study the viability of the $ω_0 ω_a$CDM cosmological model to explain the clustered Universe. Our analyses compare the $ω_0 ω_a$CDM model with the $σ_8(z)$ function reconstructed from the data points using Gaussian Process. Moreover, we perform a similar evaluation of the $Λ$CDM model considering Planck and~DESI best-fit parameters. In addition, we implemented robustness tests regarding Gaussian Process reconstruction to support our results. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_00779 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Is $ω_0 ω_a$CDM a good model for the clumpy Universe? Oliveira, Fernanda Avila, Felipe Franco, Camila Bernui, Armando Cosmology and Nongalactic Astrophysics The DESI collaboration just obtained a set of precise BAO measurements, that combined with CMB and SNIa datasets show that the $ω_0 ω_a$CDM model is preferred over $Λ$CDM, at more than $4\,σ$, to describe the dynamics of the expanding Universe. This raises the question whether this model also suitably describes the clumpy Universe. Also lately, detailed analyses of diverse cosmic tracers resulted in a new dataset of measurements of an observable from the clumpy Universe: $σ_8(z)$, spanning a high-redshift data $z \in [0.013, 3.8]$. In this work we use this dataset of 15 $σ_8(z_i)$ measurements to study the viability of the $ω_0 ω_a$CDM cosmological model to explain the clustered Universe. Our analyses compare the $ω_0 ω_a$CDM model with the $σ_8(z)$ function reconstructed from the data points using Gaussian Process. Moreover, we perform a similar evaluation of the $Λ$CDM model considering Planck and~DESI best-fit parameters. In addition, we implemented robustness tests regarding Gaussian Process reconstruction to support our results. |
| title | Is $ω_0 ω_a$CDM a good model for the clumpy Universe? |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2507.00779 |