Accelerated cosmological models in modified gravity tested by distant supernovae SNIa data
- Institute of Theoretical Physics, University of Wroclaw, pl. Maksa Borna 9, 50-204 Wroclaw (Poland) (Poland)
- Astronomical Observatory , Jagiellonian University, 30-244 Cracow, ul. Orla 171 (Poland)
- Astronomical Observatory , Jagiellonian University, 30-244 Cracow, ul. Orla 171 (Poland) and Mark Kac International Centre for Complex and Quantum Systems, Institute of Physics, Jagiellonian University, 30-244 Cracow, ul. Orla 171 (Poland)
Recent type Ia supernova measurements and other astronomical observations suggest that our Universe is, at the present epoch, in an accelerating phase of evolution. While a dark energy of unknown form and origin is usually proposed as the most feasible mechanism for the acceleration, there appeared some generalizations of Einstein equations which could mimic dark energy. In this work we investigate observational constraints on a modified Friedmann equation obtained from the generalized Lagrangian L{proportional_to}R{sup n} minimally coupled with matter via the Palatini first-order formalism. We mainly concentrate on such restrictions of model parameters which can be derived from distant supernovae and baryon oscillation tests. We obtain confidence levels for two parameters (n, {omega}{sub m,0}) and find, from combined analysis, that the preferred value of {omega}{sub m,0} equals 0.3. For deeper statistical analysis and for comparison of our model with predictions of the {lambda}CDM concordance model, one applies Akaike and Bayesian information criteria of model selection. Finally, we conclude that the Friedmann-Robertson-Walker model merged with a first-order nonlinear gravity survives SNIa and baryon oscillation tests.
- OSTI ID:
- 20870948
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 74, Issue 4; Other Information: DOI: 10.1103/PhysRevD.74.043502; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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