Features in the dark energy equation of state and modulations in the Hubble diagram
- Institute of High Energy Physics, Chinese Academy of Science, P.O. Box 918-4, Beijing 100049 (China)
- Research Center for the Early Universe (RESCEU), Graduate School of Science, University of Tokyo, Tokyo 113-0033 (Japan)
We probe the time dependence of the dark energy equation of state (EOS) in light of three-year WMAP (WMAP3) and the combination with other tentative cosmological observations from galaxy clustering (SDSS) and Type Ia Supernova (SNIa). We mainly focus on cases where the EOS is oscillating or with local bumps. By performing a global analysis with the Markov Chain Monte Carlo (MCMC) method, we find the current observations, in particular, the WMAP3 + SDSS data combination, allow large oscillations of the EOS which can leave oscillating features on the (residual) Hubble diagram, and such oscillations are potentially detectable by future observations like SNAP, or even by the currently ongoing SNIa observations. Local bumps of dark energy EOS can also leave imprints on CMB, LSS and SNIa. In cases where the bumps take place at low redshifts and the effective EOS is close to -1, CMB and LSS observations cannot give stringent constraints on such possibilities. However, geometrical observations like (future) SNIa can possibly detect such features. On the other hand when the local bumps take place at higher redshifts beyond the detectability of SNIa, future precise observations like Gamma-ray bursts, CMB and LSS may possibly detect such features. In particular, we find that bumplike dark energy EOS on high redshifts might be responsible for the localized features of WMAP on ranges l{approx}20-40, which is interesting and deserves addressing further.
- OSTI ID:
- 20871391
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 74, Issue 8; Other Information: DOI: 10.1103/PhysRevD.74.083521; (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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