Constraints on Λ(t)CDM cosmology using cosmic chronometers and supernova data
Myrzakulov Y. Koussour M. Bulanbay M. Muminov S. Rayimbaev J.
April 2025Elsevier B.V.
Chinese Journal of Physics
2025#94287 - 297 pp.
In this manuscript, we investigate the constraints on dynamical vacuum models within the framework of Λ(t)CDM cosmology by assuming a parameterization of the vacuum energy density as ρΛ(t)=ρΛ01+α(1−a), where ρΛ0 is the present vacuum density and α is a free parameter. We use 31 cosmic chronometer data points and 1048 Pantheon type Ia supernova samples to constrain the model parameters. Our statistical analysis employs Markov Chain Monte Carlo (MCMC) simulations. We have found that the universe is currently undergoing accelerated expansion, transitioning from a decelerating phase. The transition redshift zt=0.65−0.19+0.03 obtained from the combined CC+SNe dataset is consistent with recent constraints. The total EoS indicates an accelerating phase, with density parameters for matter and vacuum energy exhibiting expected behaviors. The Om(z) diagnostic shows distinct behaviors for different datasets, and the present value of the jerk parameter deviates slightly from the ΛCDM model but remains consistent within uncertainties. These findings support the dynamic nature of dark energy and provide valuable constraints on the evolution of the universe.
Dark energy , Dynamical vacuum models , MCMC , Observational constraints
Text of the article Перейти на текст статьи
Department of General & Theoretical Physics, L.N. Gumilyov Eurasian National University, Astana, 010008, Kazakhstan
Department of Physics, University of Hassan II Casablanca, Morocco
Mamun University, Bolkhovuz Street 2, Khiva, 220900, Uzbekistan
Institute of Fundamental and Applied Research, National Research University TIIAME, Kori Niyoziy 39, Tashkent, 100000, Uzbekistan
University of Tashkent for Applied Sciences, Str. Gavhar 1, Tashkent, 100149, Uzbekistan
Urgench State University, Kh. Alimjan Str. 14, Urgench, 221100, Uzbekistan
Shahrisabz State Pedagogical Institute, Shahrisabz Str. 10, Shahrisabz, 181301, Uzbekistan
Department of General & Theoretical Physics
Department of Physics
Mamun University
Institute of Fundamental and Applied Research
University of Tashkent for Applied Sciences
Urgench State University
Shahrisabz State Pedagogical Institute
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026