Cosmological constraints on time-varying cosmological terms: A study of FLRW universe models with $Λ(t)$CDM cosmology
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arXiv
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| Auteurs principaux: | , , |
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| Format: | Preprint |
| Publié: |
2024
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| _version_ | 1866910443855937536 |
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| author | Koussour, M. Myrzakulov, N. Rayimbaev, J. |
| author_facet | Koussour, M. Myrzakulov, N. Rayimbaev, J. |
| contents | This paper explores models of the FLRW universe that incorporate a time-varying cosmological term $Λ(t)$. Specifically, we assume a power-law form for the cosmological term as a function of the scale factor: $Λ(t)=Λ_{0} a(t)^{-α}$, where $Λ_{0}$ represents the present value of the cosmological term. Then, we derive an exact solution to Einstein's field equations within the framework of $Λ(t)$CDM cosmology and determine the best-fit values of the model parameters using the combined $H(z)$ + SNe Ia dataset and MCMC analysis. Moreover, the deceleration parameter demonstrates the accelerating behavior of the universe, highlighting the transition redshift $z_{tr}$, at which the expansion shifts from deceleration to acceleration, with confidence levels of $1-σ$ and $2-σ$. In addition, we analyze the behavior of the Hubble parameter, jerk parameter, and $Om(z)$ diagnostic. Our analysis leads us to the conclusion that the $Λ(t)$CDM model is consistent with present-day observations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_15982 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Cosmological constraints on time-varying cosmological terms: A study of FLRW universe models with $Λ(t)$CDM cosmology Koussour, M. Myrzakulov, N. Rayimbaev, J. Cosmology and Nongalactic Astrophysics This paper explores models of the FLRW universe that incorporate a time-varying cosmological term $Λ(t)$. Specifically, we assume a power-law form for the cosmological term as a function of the scale factor: $Λ(t)=Λ_{0} a(t)^{-α}$, where $Λ_{0}$ represents the present value of the cosmological term. Then, we derive an exact solution to Einstein's field equations within the framework of $Λ(t)$CDM cosmology and determine the best-fit values of the model parameters using the combined $H(z)$ + SNe Ia dataset and MCMC analysis. Moreover, the deceleration parameter demonstrates the accelerating behavior of the universe, highlighting the transition redshift $z_{tr}$, at which the expansion shifts from deceleration to acceleration, with confidence levels of $1-σ$ and $2-σ$. In addition, we analyze the behavior of the Hubble parameter, jerk parameter, and $Om(z)$ diagnostic. Our analysis leads us to the conclusion that the $Λ(t)$CDM model is consistent with present-day observations. |
| title | Cosmological constraints on time-varying cosmological terms: A study of FLRW universe models with $Λ(t)$CDM cosmology |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2404.15982 |