Cosmological milestones and energy conditions

Cattoën, Céline; Visser, Matt

doi:10.1088/1742-6596/68/1/012011

Cited by 38 publications

(45 citation statements)

References 9 publications

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“…Analogously, it would be interesting to expand commonly used notions of cosmological distances. Following the prescriptions given in [28], we consider four alternative distances, namely the photon flux distance d F , the photon count distance d P , the deceleration distance d Q and the angular diameter distance d A . To define those distances in a self-consistent way, we construct the following relations:…”

Section: Cosmography With the Hubble Parameter And Beyondmentioning

confidence: 99%

“…(56) may give misleading results since, at arbitrary order n, the case z → ∞ leads to a divergence in the equation of state 28 . A reasonable approach, first proposed by Chevallier-Polarski [57] and immediately afterwards by Linder [58], with two other independent researchers, pointed out that a direct generalisation of Eq.…”

Section: The Chevallier-polarski-linder Parametrizationmentioning

confidence: 99%

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On the theory and applications of modern cosmography

Dunsby

Luongo

2016

Int. J. Geom. Methods Mod. Phys.

160

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Cosmography represents an important branch of cosmology which aims to describe the universe without the need of postulating a priori any particular cosmological model. All quantities of interest are expanded as a Taylor series around here and now, providing in principle, a way of directly matching with cosmological data. In this way, cosmography can be regarded a model-independent technique, able to fix cosmic bounds, although several issues limit its use in various model reconstructions. The main purpose of this review is to focus on the key features of cosmography, emphasising both the strategy for obtaining the observable cosmographic series and pointing out any drawbacks which might plague the standard cosmographic treatment. In doing so, we relate cosmography to the most relevant cosmological quantities and to several dark energy models. We also investigate whether cosmography is able to provide information about the form of the cosmological expansion history, discussing how to reproduce the dark fluid from the cosmographic sound speed. Following this, we discuss limits on cosmographic priors and focus on how to experimentally treat cosmographic expansions. Finally, we present some of the latest developments of the cosmographic method, reviewing the use of rational approximations, based on cosmographic Padé polynomials. Future prospects leading to more accurate cosmographic results, able to better reproduce the expansion history of the universe are also discussed in detail.

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Section: Cosmography With the Hubble Parameter And Beyondmentioning

confidence: 99%

Section: The Chevallier-polarski-linder Parametrizationmentioning

confidence: 99%

On the theory and applications of modern cosmography

Dunsby

Luongo

2016

Int. J. Geom. Methods Mod. Phys.

160

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“…If these errors turn out to be big, the positive aspects of cosmography will vanish. For instance, if the error on q 0 allows for a positive value of the deceleration parameter in the 3σ confidence interval, it will not be so obvious that the Universe is accelerating (see again [2]). Moreover, the ΛCDM model enforces j 0 = 1 (this can be easily derived from the definition of j 0 , which is to be found in § (III)); but if the error bar is as big as reported above (from [4]), it will not be possible to confront this model with competing ones.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive cosmographic analysis by Markov chain method

2011

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We study the possibility to extract model independent information about the dynamics of the universe by using Cosmography. We intend to explore it systematically, to learn about its limitations and its real possibilities. Here we are sticking to the series expansion approach on which Cosmography is based. We apply it to different data sets: Supernovae Type Ia (SNeIa), Hubble parameter extracted from differential galaxy ages, Gamma Ray Bursts (GRBs) and the Baryon Acoustic Oscillations (BAO) data. We go beyond past results in the literature extending the series expansion up to the fourth order in the scale factor, which implies the analysis of the deceleration, q0, the jerk, j0 and the snap, s0. We use the Markov Chain Monte Carlo Method (MCMC) to analyze the data statistically. We also try to relate direct results from Cosmography to dark energy (DE) dynamical models parameterized by the Chevalier-Polarski-Linder (CPL) model, extracting clues about the matter content and the dark energy parameters. The main results are: a. even if relying on a mathematical approximate assumption such as the scale factor series expansion in terms of time, cosmography can be extremely useful in assessing dynamical properties of the Universe; b. the deceleration parameter clearly confirms the present acceleration phase; c. the MCMC method can help giving narrower constraints in parameter estimation, in particular for higher order cosmographic parameters (the jerk and the snap), with respect to the literature; d. both the estimation of the jerk and the DE parameters, reflect the possibility of a deviation from the ΛCDM cosmological model.

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“…The statefinder diagnostic has been extensively used in many models (Gorini et al 2003). But the statefinder pair is difficult to measure with cosmological observations (Visser 2004;Cattoën & Visser 2007).…”

Section: Introductionmentioning

confidence: 99%

Probing the cosmographic parameters to distinguish between dark energy and modified gravity models

Wang

Dai

2009

A&A

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Aims. In this paper we investigate the deceleration, jerk and snap parameters to distinguish between the dark energy and modified gravity models using high redshift gamma-ray bursts (GRBs) and supernovae (SNe). Methods. We first derive the expressions of deceleration, jerk and snap parameters in dark energy and modified gravity models. In order to constrain the cosmographic parameters, we calibrate the GRB luminosity relations without assuming any cosmological models using SNe Ia. Then we constrain the model parameters (including dark energy and modified gravity models) using type Ia supernovae and gamma-ray bursts. Finally we calculate the cosmographic parameters. GRBs can extend the redshift-distance relation up to high redshifts, because they can be detected to high redshifts. Results. We find that the statefinder pair (r, s) could not be used to distinguish between some dark energy and modified gravity models, but these models could be differentiated by the snap parameter. Using the model-independent constraints on cosmographic parameters, we conclude that the ΛCDM model is consistent with current data.

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Cosmological milestones and energy conditions

Cited by 38 publications

References 9 publications

On the theory and applications of modern cosmography

On the theory and applications of modern cosmography

Comprehensive cosmographic analysis by Markov chain method

Probing the cosmographic parameters to distinguish between dark energy and modified gravity models

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