Exploring the Growth Index $γ_L$: Insights from Different CMB Dataset Combinations and Approaches
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arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2023
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| _version_ | 1866917595862532096 |
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| author | Specogna, Enrico Di Valentino, Eleonora Said, Jackson Levi Nguyen, Nhat-Minh |
| author_facet | Specogna, Enrico Di Valentino, Eleonora Said, Jackson Levi Nguyen, Nhat-Minh |
| contents | In this study we investigate the growth index $γ_L$, which characterizes the growth of linear matter perturbations, while analysing different cosmological datasets. We compare the approaches implemented by two different patches of the cosmological solver CAMB: MGCAMB and CAMB_GammaPrime_Growth. In our analysis we uncover a deviation of the growth index from its expected $Λ$CDM value of $0.55$ when utilizing the Planck dataset, both in the MGCAMB case and in the CAMB_GammaPrime_Growth case, but in opposite directions. This deviation is accompanied by a change in the direction of correlations with derived cosmological parameters. However, the incorporation of CMB lensing data helps reconcile $γ_L$ with its $Λ$CDM value in both cases. Conversely, the alternative ground-based telescopes ACT and SPT consistently yield growth index values in agreement with $γ_L=0.55$. We conclude that the presence of the A$_{\mathrm{lens}}$ problem in the Planck dataset contributes to the observed deviations, underscoring the importance of additional datasets in resolving these discrepancies. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2305_16865 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Exploring the Growth Index $γ_L$: Insights from Different CMB Dataset Combinations and Approaches Specogna, Enrico Di Valentino, Eleonora Said, Jackson Levi Nguyen, Nhat-Minh Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology In this study we investigate the growth index $γ_L$, which characterizes the growth of linear matter perturbations, while analysing different cosmological datasets. We compare the approaches implemented by two different patches of the cosmological solver CAMB: MGCAMB and CAMB_GammaPrime_Growth. In our analysis we uncover a deviation of the growth index from its expected $Λ$CDM value of $0.55$ when utilizing the Planck dataset, both in the MGCAMB case and in the CAMB_GammaPrime_Growth case, but in opposite directions. This deviation is accompanied by a change in the direction of correlations with derived cosmological parameters. However, the incorporation of CMB lensing data helps reconcile $γ_L$ with its $Λ$CDM value in both cases. Conversely, the alternative ground-based telescopes ACT and SPT consistently yield growth index values in agreement with $γ_L=0.55$. We conclude that the presence of the A$_{\mathrm{lens}}$ problem in the Planck dataset contributes to the observed deviations, underscoring the importance of additional datasets in resolving these discrepancies. |
| title | Exploring the Growth Index $γ_L$: Insights from Different CMB Dataset Combinations and Approaches |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2305.16865 |