Age constraints on the cosmic equation of state

Dantas, M. A.; Alcaniz, J. S.; Jain, Deepak; Dev, Abha

doi:10.1051/0004-6361:20066632

Cited by 46 publications

(46 citation statements)

References 41 publications

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“…This means that, for d f = 0 Gyr and by considering the Hubble parameter within the current accepted interval, even at very high redshifts, i.e., z 1, when the Universe is expected to be dominated by normal matter, all the lookback time estimates discussed here are at least 1σ higher than the theoretical value derived from Eq. (17). A slightly different conclusion is obtained by considering a delay factor of d f = 0.5 Gyr [ Fig.…”

Section: Secmentioning

confidence: 94%

Lookback time bounds from energy conditions

et al. 2007

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In general relativity, the energy conditions are invoked to restrict general energy-momentum tensors on physical grounds. We show that in the standard Friedmann-Lemaître-Robertson-Walker (FLRW) approach to cosmological modeling, where the energy and matter components of the cosmic fluid are unknown, the energy conditions provide model-independent bounds on the behavior of the lookback time of cosmic sources as a function of the redshift for any value of the spatial curvature. We derive and confront such bounds with a lookback time sample which is built from the age estimates of 32 galaxies lying in the interval 0.11 z 1.84 and by assuming the total expanding age of the Universe to be 13.7 ± 0.2 Gyr, as obtained from current cosmic microwave background experiments. In agreement with previous results, we show that all energy conditions seem to have been violated at some point of the recent past of cosmic evolution.

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Section: Secmentioning

confidence: 94%

Lookback time bounds from energy conditions

et al. 2007

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“…After marginalizing the 'nuisance' parameter df , one can use the following method to constrain a cosmological model by using lookback time [42] …”

Section: Lookback Timementioning

confidence: 99%

Cosmic constraint to DGP brane model: Geometrical and dynamical perspectives

Wang

2010

Phys. Rev. D

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In this paper, the Dvali-Gabadadze-Porrati (DGP) brane model is confronted by current cosmic observational data sets from geometrical and dynamical perspectives. On the geometrical side, the recent released Union2 557 of type Ia supernovae (SN Ia), the baryon acoustic oscillation (BAO) from Sloan Digital Sky Survey and the Two Degree Galaxy Redshift Survey (transverse and radial to line-of-sight data points), the cosmic microwave background (CMB) measurement given by the seven-year Wilkinson Microwave Anisotropy Probe observations (shift parameters R, la(z * ) and redshift at the last scatter surface z * ), ages of high redshifts galaxies, i.e. the lookback time (LT) and the high redshift Gamma Ray Bursts (GRBs) are used. On the dynamical side, data points about the growth function (GF) of matter linear perturbations are used. Using the same data sets combination, we also constrain the flat ΛCDM model as a comparison. The results show that current geometrical and dynamical observational data sets much favor flat ΛCDM model and the departure from it is above 4σ(6σ) for spatially flat DGP model with(without) SN systematic errors. The consistence of growth function data points is checked in terms of relative departure of redshift-distance relation.

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“…Furthermore, in principle, it must be different for each object in the sample. Thus the delay factor becomes a "nuisance" parameter, we use the following method to marginalize over it [31] …”

Section: The Lookback Time-redshift Datamentioning

confidence: 99%

Testing the (generalized) Chaplygin gas model with the lookback time-redshift data

2009

J. Cosmol. Astropart. Phys.

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The Chaplygin gas (CG) and the generalized Chaplygin gas (GCG) models, proposed as candidates of the unified dark matter-dark energy (UDME), are tested with the look-back time (LT) redshift data. We find that the LT data only give a very weak constraint on the model parameter. However, by combing the LT with the baryonic acoustic oscillation peak, we obtain, at the 95.4% confidence level, 0.68 ≤ A c ≤ 0.82 and 0.59 ≤ h ≤ 0.65 for the CG model , and 0.67 ≤ A s ≤ 0.89 and −0.29 ≤ α ≤ 0.61 for the GCG model. This shows that both the CG and the GCG are viable as a candidate of UDME. Within the GCG model, we also find that the Chaplygin gas model (α = 1) is ruled out by these data at the 99.7% confidence level.

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Age constraints on the cosmic equation of state

Cited by 46 publications

References 41 publications

Lookback time bounds from energy conditions

Lookback time bounds from energy conditions

Cosmic constraint to DGP brane model: Geometrical and dynamical perspectives

Testing the (generalized) Chaplygin gas model with the lookback time-redshift data

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