WMAP and the generalized Chaplygin gas

• Verfasst von: Amendola, Luca [VerfasserIn]
• Titel: WMAP and the generalized Chaplygin gas
• Verf.angabe: L. Amendola, F. Finelli, C. Burigana and D. Carturan
• E-Jahr: 2003
• Jahr: 8 July 2003
• Umfang: 14 S.
• Fussnoten: Gesehen am 17.11.2017
• Titel Quelle: Enthalten in: Journal of cosmology and astroparticle physics
• Ort Quelle: London : IOP, 2003
• Jahr Quelle: 2003
• Band/Heft Quelle: (2003), 7, Artikel-ID 005, Seite 1-14
• ISSN Quelle: 1475-7516
• DOI: doi:10.1088/1475-7516/2003/07/005
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 156544910X

Abstract

We compare the WMAP temperature power spectrum and SNIa data to models with a generalized Chaplygin gas as dark energy. The generalized Chaplygin gas is a component with an exotic equation of state, p X = − A /ρ α X (a polytropic gas with negative constant and exponent). Our main result is that, restricting to a flat universe and to adiabatic pressure perturbations for the generalized Chaplygin gas, the constraints at 95% CL to the present equation of state w X = p X /ρ X and to the parameter α are−1 ≤ w X < −0.8, 0 ≤ α < 0.2, respectively. Moreover, we show that a Chaplygin gas (α = 1) is ruled out as a candidate for dark energy by our analysis at more than the 99.99% CL. A generalized Chaplygin gas appears much less likely as a unified dark matter candidate (Ω CDM = 0) than as a dark energy model, although its χ 2 is only two sigma away from the expected value.