Analysis of Two Quintessence Models with Type Ia Supernova Data

Pavlov, M.; Rubano, C.; Sazhin, M. V.; Scudellaro, P.

doi:10.1086/338114

Cited by 32 publications

(36 citation statements)

References 35 publications

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“…We want to mention here that, in the context of the usual minimal coupling setting, it is in fact possible to find a general exact solution, which again shows an asymptotic t 4/3 behavior [48]. This solution has been tested with a full set of data [48][49][50].…”

Section: Conclusive Remarksmentioning

confidence: 99%

Variable G and ?: scalar-tensor versus RG-improved cosmology

Rubano

Scudellaro

2005

Gen Relativ Gravit

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We study the consequences due to time varying G and Λ in scalar-tensor theories of gravity for cosmology, inspired by the modifications introduced by the Renormalization Group (RG) equations in the Quantum Einstein Gravity. We assume a power-law scale factor in presence contemporarily of both the scalar field and the matter components of the cosmic fluid, and analyze a special case and its generalization, also showing the possibility of a phantom cosmology. In both such situations we find a negative kinetic term for the scalar field Q and, possibly, an equation-of-state parameter w Q < −1. A violation of dominant energy condition (DEC) for Q is also possible in both of them; but, while in the first special case the Q-energy density then remains positive, in the second one we find it negative.

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Section: Conclusive Remarksmentioning

confidence: 99%

Variable G and ?: scalar-tensor versus RG-improved cosmology

Rubano

Scudellaro

2005

Gen Relativ Gravit

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“…As a matter of fact, some papers have already appeared, successfully comparing this model with present day observations [22][23][24]. In Sec.…”

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confidence: 99%

Exponential potentials for tracker fields

et al. 2004

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We show that a general, exact cosmological solution, where dynamics of scalar field is assigned by an exponential potential, fulfils all the issues of dark energy approach, both from a theoretical point of view and in comparison with available observational data. Moreover, tracking conditions are discussed, with a new treatment of the well known condition Γ > 1. We prove that the 1 currently used expression for Γ is wrong. PACS number(s): 98.80. Jk, 98.80.Cq, 98.80.Hw, 04.20.Jb

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“…1 Despite its simplicity, the examined exact solution reflects many properties of the observed Universe, with the same statistical confidence of a constant Λ term (Di Domenico et al 2002; Pavlov et al 2002; Rubano & Sereno 2002). It is compatible with the supernovae data, whose analysis gives Ω M0 = 0.15 +0.15 −0.03 at the 68.3 per cent confidence level (Pavlov et al 2002). The peculiar velocity field and the perturbation growth of structure can also be accounted for in this scenario (Rubano & Sereno 2002); data from galaxy clustering suggest a value of Ω M0 = 0.18 ± 0.05 at the 68 per cent confidence level.…”

Section: Discussionmentioning

confidence: 89%

Constraints on a quintessence model from gravitational lensing statistics

Sereno

2005

Monthly Notices of the Royal Astronomical Society

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Constraints on an exact quintessence scalar‐field model with an exponential potential are derived from gravitational lens statistics. An exponential potential can account for data from both optical quasar surveys and radio‐selected sources. Based on the Cosmic Lens All‐Sky Survey (CLASS) sample, lensing statistics provides, for the pressureless matter density parameter, an estimate of ΩM0= 0.31+0.12−0.14.

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Analysis of Two Quintessence Models with Type Ia Supernova Data

Abstract: The Type Ia supernovae data are used to analyze two general exact solutions for quintessence models. The best-Ðt values for are smaller than in the "-term model, but still acceptable. With present-day ) m0 data, it is not possible to discriminate among the various situations.

Cited by 32 publications

References 35 publications

Variable G and ?: scalar-tensor versus RG-improved cosmology

Variable G and ?: scalar-tensor versus RG-improved cosmology

Exponential potentials for tracker fields

Constraints on a quintessence model from gravitational lensing statistics

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