caa a22 4500 467887748 CHVBK 20180406152739.0 cr unu---uuuuu 170328e20060501xx s 000 0 eng 10.1007/s10714-006-0265-6 doi (NATIONALLICENCE)springer-10.1007/s10714-006-0265-6 Equation of state for the Universe from similarity symmetries [Elektronische Daten] [Marek Szydłowski, Włodzimierz Godłowski, Radosław Wojtak] In this paper we proposed to use the group of analysis of symmetries of the dynamical system to describe the evolution of the Universe. This method is used in searching for the unknown equation of state. It is shown that group of symmetries enforce the form of the equation of state for noninteracting scaling multifluids. We showed that symmetries give rise to the equation of state in the form p =-Λ + w 1ρ(a) + w 2 a β + 0 and energy density ρ = Λ+ρ01 a -3(1+w) +ρ02 a α +ρ03 a -3, which is commonly used in cosmology. The FRW model filled with scaling fluid (called homological) is confronted with the observations of distant type Ia supernovae. We found the class of model parameters admissible by the statistical analysis of SNIa data.We showed that the model with scaling fluid fits well to supernovae data. We found that Ωm,0 ≃ 0.4 and n ≃ -1 (β = -3n), which can correspond to (hyper) phantom fluid, and to a high density universe. However if we assume prior that Ωm,0 = 0.3 then the favoured model is close to concordance ΛCDM model. Our results predict that in the considered model with scaling fluids distant type Ia supernovae should be brighter than in the ΛCDM model, while intermediate distant SNIa should be fainter than in the ΛCDM model. We also investigate whether the model with scaling fluid is actually preferred by data over ΛCDM model. As a result we find from the Akaike model selection criterion: it prefers the model with noninteracting scaling fluid. Springer-Verlag, 2006 Equation of state nationallicence Scaling fluid nationallicence Szydłowski Marek Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków, Poland aut Godłowski Włodzimierz Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków, Poland aut Wojtak Radosław Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków, Poland aut General Relativity and Gravitation Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 38/5(2006-05-01), 795-821 0001-7701 38:5<795 2006 38 10714 https://doi.org/10.1007/s10714-006-0265-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10714-006-0265-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Szydłowski Marek Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków, Poland aut NATIONALLICENCE 700 1- Godłowski Włodzimierz Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków, Poland aut NATIONALLICENCE 700 1- Wojtak Radosław Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków, Poland aut NATIONALLICENCE 773 0- General Relativity and Gravitation Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 38/5(2006-05-01), 795-821 0001-7701 38:5<795 2006 38 10714 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer