Constraining thawing and freezing models with cluster number counts

We show that the number of observed voids in galaxy redshift surveys is a sensitive function of the equation of state of dark energy. Using the Fisher matrix formalism we find the error ellipses in the w0 − wa plane when the equation of state of dark energy is assumed to be of the form wCP L(z) = w0 + waz/(1 + z). We forecast the number of voids to be observed with the ESA Euclid satellite and the NASA WFIRST mission, taking into account updated details of the surveys to reach accurate estimates of their power. The theoretical model for the forecast of the number of voids is based on matches between abundances in simulations and the analytical prediction. To take into account the uncertainties within the model, we marginalize over its free parameters when calculating the Fisher matrices. The addition of the void abundance constraints to the data from Planck, HST and supernova survey data noticeably tighten the w0 − wa parameter space. We thus quantify the improvement in the constraints due to the use of voids and demonstrate that the void abundance is a sensitive new probe for the dark energy equation of state.

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“…[3,[60][61][62][63]). It is worth noticing that the observed void counts promise to give complementary constraints to the cluster method.…”

Section: Discussionmentioning

confidence: 99%

Counting voids to probe dark energy

et al. 2015

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“…Clearly eROSITA is expected to measure a higher number of clusters than the SPT, peaking at z ≈ 0.28 where the differences relative to ΛCDM, at this redshift, are ∆N ≈ 47 000 and ∆N ≈ 110 000 for β = 0.05 and β = 0.08, respectively. These numbers are much higher than the expected eROSITA sensitivity of ∆N ≈ 500 [42,76] suggesting once again a possibility to discriminate between models with eROSITA. The values found for N with β = 0 (ΛCDM) are, as expected, consistent with prior studies [65,81].…”

Section: Observationsmentioning

confidence: 77%

“…In regard to our previous analysis, we follow to compute the predicted number of cluster-sized objects for future surveys and shed some light on their ability to distinguish between theoretical models. Prior studies have implemented a similar analysis for different theoretical models, such as disformally coupled [65], thawing [73] and freezing [76] models of dark energy.…”

Section: Observationsmentioning

confidence: 99%

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Spherical collapse in coupled quintessence with a ΛCDM background

2020

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In this work we study the growth of cold dark matter density perturbations in the nonlinear regime on a conformally coupled quintessence model in which the background is designed to mimic a ΛCDM cosmology. The spherical collapse of overdense regions is analysed. We highlight the role of the coupling on the overall dynamics, trace the evolution of the density contrast throughout the cosmic history and compute perturbative parameters such as the critical density contrast. We find that the coupling has the influence of delaying the collapse due to the slower growth of matter perturbations. We follow to compute the cluster number counts using the Press-Schechter and Sheth-Tormen mass functions. In both cases, the transfer of energy between the dark energy field and dark matter suppresses the number of objects at low redshifts and enhances the number at high redshifts. Finally, we compute the expected cluster number counts for two future surveys -eROSITA and the South Pole Telescope -and shed some light on the possibility of discriminating models with these missions.

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“…It is found that there is hardly any reason to favour any of these two if the complete history of universe in the post radiation-dominated is considered. Thawing and freezing models, in terms of cluster number counts, have been discussed by Devi, Gonzales and Alcaniz [18]. The purpose of the present work is to compare the thawing and freezing models considering their thermodynamic behaviour, particularly their viability against the generalized second law (GSL) of thermodynamics.…”

Section: Introductionmentioning

confidence: 99%

Thawing and freezing quintessence models: a thermodynamic consideration

2019

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Thawing and freezing quintessence models are compared thermodynamically. Both of them are found to disobey the Generalized Second Law of Thermodynamics. However, for freezing models, there is still a scope as this breakdown occurs in the past, deep inside the radiation dominated era, when a standard scalar field model with a pressureless matter is not a correct description of the matter content. The thawing model has a pathological breakdown in terms of thermodynamics in a finite future.

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Constraining thawing and freezing models with cluster number counts

Cited by 13 publications

References 84 publications

Counting voids to probe dark energy

Counting voids to probe dark energy

Spherical collapse in coupled quintessence with a ΛCDM background

Thawing and freezing quintessence models: a thermodynamic consideration

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