Interpreting DESI 2024 BAO: late-time dynamical dark energy or a local effect?
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arXiv
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| Auteurs principaux: | , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866913706924834816 |
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| author | Gialamas, Ioannis D. Hütsi, Gert Kannike, Kristjan Racioppi, Antonio Raidal, Martti Vasar, Martin Veermäe, Hardi |
| author_facet | Gialamas, Ioannis D. Hütsi, Gert Kannike, Kristjan Racioppi, Antonio Raidal, Martti Vasar, Martin Veermäe, Hardi |
| contents | We perform fits to DESI, CMB and supernova data to understand the physical origin of the DESI hint for dynamical dark energy. We find that the linear parametrization of the equation of state $w$ may guide to misleading interpretations, such as the hint for a phantom Universe, which are not preferred by the data. Instead, physical quintessence models fit the data well. Model-independently, present observations prefer deviations from the constant dark energy, $w=-1$, only at very low redshifts, $z < \mathcal{O}(0.1)$. We find that this result is driven by low-$z$ supernova data. Therefore, either the fundamental properties of our Universe, characterised by the equation of state $w$ and the Hubble parameter $H$, underwent dramatic changes very recently or, alternatively, we do not fully understand the systematics of our local Universe in a radius of about $300\,h^{-1}\rm Mpc$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2406_07533 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Interpreting DESI 2024 BAO: late-time dynamical dark energy or a local effect? Gialamas, Ioannis D. Hütsi, Gert Kannike, Kristjan Racioppi, Antonio Raidal, Martti Vasar, Martin Veermäe, Hardi Cosmology and Nongalactic Astrophysics High Energy Physics - Phenomenology We perform fits to DESI, CMB and supernova data to understand the physical origin of the DESI hint for dynamical dark energy. We find that the linear parametrization of the equation of state $w$ may guide to misleading interpretations, such as the hint for a phantom Universe, which are not preferred by the data. Instead, physical quintessence models fit the data well. Model-independently, present observations prefer deviations from the constant dark energy, $w=-1$, only at very low redshifts, $z < \mathcal{O}(0.1)$. We find that this result is driven by low-$z$ supernova data. Therefore, either the fundamental properties of our Universe, characterised by the equation of state $w$ and the Hubble parameter $H$, underwent dramatic changes very recently or, alternatively, we do not fully understand the systematics of our local Universe in a radius of about $300\,h^{-1}\rm Mpc$. |
| title | Interpreting DESI 2024 BAO: late-time dynamical dark energy or a local effect? |
| topic | Cosmology and Nongalactic Astrophysics High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2406.07533 |