Cosmological constraints on time-varying cosmological terms: A study of FLRW universe models with Λ(t)CDM cosmology
Koussour M. Myrzakulov N. Rayimbaev J.
1 August 2024Elsevier Ltd
Advances in Space Research
2024#74Issue 31343 - 1351 pp.
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)=Λ0a(t)-α, where Λ0 represents the present value of the cosmological term. Then, we derive an exact solution to Einsteins 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 ztr, 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.
Cosmological constraints , Dark energy , Deceleration parameter , Λ(t)CDM
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University of Hassan II Casablanca, Av Driss El Harti Sidi Othmane, Casablanca, 07955, Morocco
L. N. Gumilyov Eurasian National University, Satpayev 2, Astana, 010008, Kazakhstan
New Uzbekistan University, Mustaqillik Ave. 54, Tashkent, 100007, Uzbekistan
University of Tashkent for Applied Sciences, Gavhar Str. 1, Tashkent, 100149, Uzbekistan
National University of Uzbekistan, University Street 4, Tashkent, 100174, Uzbekistan
University of Hassan II Casablanca
L. N. Gumilyov Eurasian National University
New Uzbekistan University
University of Tashkent for Applied Sciences
National University of Uzbekistan
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