Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at <i>z</i> ∼ 2

Moresco, M.

doi:10.1093/mnrasl/slv037

Cited by 788 publications

(419 citation statements)

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“…One is cosmic chronometers, which are mainly passively evolving galaxies. There are 21 data points compiled by Moresco et al [25,26]. The other is radial baryon acoustic oscillations from galaxy clustering in redshift surveys, which gives seven data points of Hubble parameters from different experiments [27][28][29][30].…”

Section: A Gaussian Processesmentioning

confidence: 99%

Null test of the cosmic curvature usingH(z)and supernovae data

2016

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We introduce a model-independent approach to the null test of the cosmic curvature which is geometrically related to the Hubble parameter H(z) and luminosity distance dL(z). Combining the independent observations of H(z) and dL(z), we use the model-independent smoothing technique, Gaussian processes, to reconstruct them and determine the cosmic curvature Ω (0) K in the null test relation. The null test is totally geometrical and does not assume any cosmological model. We show that the cosmic curvature Ω (0) K = 0 is consistent with current observational data sets, falling within the 1σ limit. To demonstrate the effect on the precision of the null test, we produce a series of simulated data of the models with different Ω 98.80.Es, 98.80Jk

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Section: A Gaussian Processesmentioning

confidence: 99%

Null test of the cosmic curvature usingH(z)and supernovae data

2016

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“…To avoid possible correlations and to assure data independence, we also excluded the three data points from [40], at z = 0.44, z = 0.60 and z = 0.68, since the same data is used in our CMB/BAO analysis [15]. In our compilation we have also included two new measurements from cosmic chronometers at redshifts 1.363 and 1.965 from [24]. In order to constrain the θ parameters of the model we use the following χ 2 H function…”

Section: H(z)mentioning

confidence: 99%

Constraining the cosmic deceleration-acceleration transition with type Ia supernova, BAO/CMB and H(z) data

Santos

Reis

Waga

2016

J. Cosmol. Astropart. Phys.

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Abstract. We revisit the kink-like parametrization of the deceleration parameter q(z) [1], which considers a transition, at redshift z t , from cosmic deceleration to acceleration. In this parametrization the initial, at z z t , value of the q-parameter is q i , its final, z = −1, value is q f and the duration of the transition is parametrized by τ . By assuming a flat space geometry we obtain constraints on the free parameters of the model using recent data from type Ia supernovae (SN Ia), baryon acoustic oscillations (BAO), cosmic microwave background (CMB) and the Hubble parameter H(z). The use of H(z) data introduces an explicit dependence of the combined likelihood on the present value of the Hubble parameter H 0 , allowing us to explore the influence of different priors when marginalizing over this parameter. We also study the importance of the CMB information in the results by considering data from WMAP7, WMAP9 (Wilkinson Microwave Anisotropy Probe -7 and 9 years) and Planck 2015. We show that the contours and best fit do not depend much on the different CMB data used and that the considered new BAO data is responsible for most of the improvement in the results. Assuming a flat space geometry, q i = 1/2 and expressing the present value of the deceleration parameter q 0 as a function of the other three free parameters, we obtain z t = 0.67 +0.10 −0.08 , τ = 0.26 +0.14 −0.10 and q 0 = −0.48 +0.11 −0.13 , at 68% of confidence level, with an uniform prior over H 0 . If in addition we fix q f = −1, as in flat ΛCDM, DGP and Chaplygin quartessence that are special models described by our parametrization, we get z t = 0.66 +0.03 −0.04 , τ = 0.33 +0.04 −0.04 and q 0 = −0.54 +0.05 −0.07 , in excellent agreement with flat ΛCDM for which τ = 1/3. We also obtain for flat wCDM, another dark energy model described by our parametrization, the constraint on the equation of state parameter −1.22 < w < −0.78 at more than 99% confidence level.

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“…In order to constrain the proposed models with recent observational data, we use N SN = 580 data points for Type Ia supernovae from Union 2.1 [59], N H = 39 observed Hubble data points [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75] and N BAO = 17 baryon acoustic oscillation data [66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84], and finally the cosmic microwave background radiation (CMB) in the form [85].…”

Section: Joint Analysismentioning

confidence: 99%

A model with interaction of dark components and recent observational data

Pan

Sharov

2017

Monthly Notices of the Royal Astronomical Society

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In the proposed model with interaction between dark energy and dark matter, we consider cosmological scenarios with different equations of state (w d ) for dark energy. For both constant and variable equation of state, we analyze solutions for dark energy and dark matter in seven variants of the model. We investigate exact analytic solutions for w d = constant equation of state, and several variants of the model for variable w d . These scenarios are tested with the current astronomical data from Type Ia Supernovae, baryon acoustic oscillations, Hubble parameter H(z) and the cosmic microwave background radiation. Finally, we make a statistical comparison of our interacting model with ΛCDM as well as with some other well known non-interacting cosmological models. The current accelerated expansion of the universe ascertained from several astronomical sources [1][2][3][4][5][6][7] is one of the appealing fields of research in modern cosmology. To explain such accelerated expansion, either one needs some hypothetical dark energy fluid in the framework of general relativity or claims direct modifications into the gravitational sector leading to several modified gravity theories. However, a large number of observational data favor the existence of ΛCDM-cosmology where the cosmological constant fluid acts as a hypothetical dark energy fluid occupying almost two third of the total energy density of the universe and the cold dark matter (CDM) fluid is responsible for the structure formation of the universe. Nevertheless, the cosmological constant problem [8] and the cosmic coincidence problem [9] associated with the ΛCDM cosmology lead to several alternative descriptions aiming to decode the dynamics of the universe, such as the dynamical dark energy models, modified gravity models, and some others. For a comprehensive discussions on such models and their effects on the dynamics of the universe, we refer [10].Amongst several dark energy and modified gravity models, interacting dark energy models have gained significant attention due to having a reasonable explanation to the cosmic coincidence problem. A number of investigations in this direction have been performed during last couple of years [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. Recently, a series of analysis shows that the current observational data prefer a nonzero interaction in the dark sector [28][29][30][31][32][33]. On the other hand, the dark sector's interaction may alleviate the current tension on local value of the Hubble constant and on σ 8 as well [31,32,[34][35][36]. Further, it has been discussed that some appropriate choice of an interaction between the dark components can influence effectively on the perturbation analysis which results in quite no- * Electronic address: span@iiserkol.ac.in † Electronic address: Sharov.GS@tversu.ru table differences in the lowest multipoles of the cosmic microwave background spectrum [37,38]. And sometimes it is possible to address the phantom universe [39][40][41][42][43][44] by a non...

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Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at z ∼ 2

Cited by 788 publications

References 32 publications

Null test of the cosmic curvature usingH(z)and supernovae data

Null test of the cosmic curvature usingH(z)and supernovae data

Constraining the cosmic deceleration-acceleration transition with type Ia supernova, BAO/CMB and H(z) data

A model with interaction of dark components and recent observational data

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