The matter with(in) CPL
We introduce a two-parameter phenomenological extension of the $\Lambda$CDM model in which the equation of state parameter of the ``dust'' fluid becomes different from zero for redshifts below a transition value $z_t$. Using data from DESI DR2 BAO, DESY5 Sn~Ia and CMB distance priors ($R,l...
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| Format: | Article |
| Language: | English |
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Maynooth Academic Publishing
2025-07-01
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| Series: | The Open Journal of Astrophysics |
| Online Access: | https://doi.org/10.33232/001c.142699 |
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| _version_ | 1849245722660044800 |
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| author | Leonardo Giani Rodrigo Von Marttens Oliver Fabio Piattella |
| author_facet | Leonardo Giani Rodrigo Von Marttens Oliver Fabio Piattella |
| author_sort | Leonardo Giani |
| collection | DOAJ |
| description | We introduce a two-parameter phenomenological extension of the $\Lambda$CDM model in which the equation of state parameter of the ``dust'' fluid becomes different from zero for redshifts below a transition value $z_t$. Using data from DESI DR2 BAO, DESY5 Sn~Ia and CMB distance priors ($R,l_A,\omega_b$) data, we compare our model with the standard CPL parameterization $w_0-w_a$ for dynamical dark energy. Using the Deviance Information Criteria (DIC), we find that the two models are essentially indistinguishable ($\Delta$DIC $<$ 2) and preferred over $\Lambda$CDM with a significance $\geq 3 \sigma$. We discuss how this parameterization finds a natural interpretation in the context of cosmological backreaction and derive a prediction for the evolution of the growth factor, discussing its impact on low redshift $f\sigma_8$ measurements. |
| format | Article |
| id | doaj-art-1a0c62474d8b44eb96fe67faf7ffeb07 |
| institution | Kabale University |
| issn | 2565-6120 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Maynooth Academic Publishing |
| record_format | Article |
| series | The Open Journal of Astrophysics |
| spelling | doaj-art-1a0c62474d8b44eb96fe67faf7ffeb072025-08-20T03:58:44ZengMaynooth Academic PublishingThe Open Journal of Astrophysics2565-61202025-07-01810.33232/001c.142699The matter with(in) CPLLeonardo GianiRodrigo Von MarttensOliver Fabio PiattellaWe introduce a two-parameter phenomenological extension of the $\Lambda$CDM model in which the equation of state parameter of the ``dust'' fluid becomes different from zero for redshifts below a transition value $z_t$. Using data from DESI DR2 BAO, DESY5 Sn~Ia and CMB distance priors ($R,l_A,\omega_b$) data, we compare our model with the standard CPL parameterization $w_0-w_a$ for dynamical dark energy. Using the Deviance Information Criteria (DIC), we find that the two models are essentially indistinguishable ($\Delta$DIC $<$ 2) and preferred over $\Lambda$CDM with a significance $\geq 3 \sigma$. We discuss how this parameterization finds a natural interpretation in the context of cosmological backreaction and derive a prediction for the evolution of the growth factor, discussing its impact on low redshift $f\sigma_8$ measurements.https://doi.org/10.33232/001c.142699 |
| spellingShingle | Leonardo Giani Rodrigo Von Marttens Oliver Fabio Piattella The matter with(in) CPL The Open Journal of Astrophysics |
| title | The matter with(in) CPL |
| title_full | The matter with(in) CPL |
| title_fullStr | The matter with(in) CPL |
| title_full_unstemmed | The matter with(in) CPL |
| title_short | The matter with(in) CPL |
| title_sort | matter with in cpl |
| url | https://doi.org/10.33232/001c.142699 |
| work_keys_str_mv | AT leonardogiani thematterwithincpl AT rodrigovonmarttens thematterwithincpl AT oliverfabiopiattella thematterwithincpl AT leonardogiani matterwithincpl AT rodrigovonmarttens matterwithincpl AT oliverfabiopiattella matterwithincpl |