Is the Hubble crisis connected with the extinction of dinosaurs?

Perivolaropoulos, Leandros

doi:10.48550/arxiv.2201.08997

Cited by 10 publications

(12 citation statements)

References 49 publications

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“…physically explain an abrupt jump in G, e. g. [68][69][70]105]. 10 See [108] for a potential explanation in f (R) gravity.…”

Section: Classmentioning

confidence: 99%

Is Local $H_0$ At Odds With Dark Energy EFT?

Lee,

Colgáin

et al. 2022

Preprint

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Local H 0 determinations currently fall in a window between H 0 ∼ 70 km/s/Mpc (TRGB) and H 0 ∼ 76 km/s/Mpc (Tully-Fisher). In contrast, BAO data calibrated in an early ΛCDM universe are largely consistent with Planck-ΛCDM, H 0 ∼ 67.5 km/s/Mpc. Employing a generic two parameter family of evolving equations of state (EoS) for dark energy (DE) w DE (z) and mock BAO data, we demonstrate that if i) w DE (z = 0) < −1 and ii) integrated DE density less than ΛCDM, then H 0 increases. EoS that violate these conditions at best lead to modest H 0 increases within 1σ. Tellingly, Quintessence and K-essence satisfy neither condition, whereas coupled Quintessence can only satisfy ii). Beyond these seminal DE Effective Field Theories (EFTs), we turn to explicit examples. Working model agnostically in an expansion in powers of redshift z, we show that Brans-Dicke/ f (R) and Kinetic Gravity Braiding models within the Horndeski class can lead to marginal and modest increases in H 0 , respectively. We confirm that as far as increasing H 0 is concerned, no DE EFT model can outperform the phenomenological two parameter family of the DE models. Evidently, the late universe may no longer be large enough to accommodate H 0 , BAO and DE described by EFT.

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“…physically explain an abrupt jump in G, e. g. [68][69][70]105]. 10 See [108] for a potential explanation in f (R) gravity.…”

Section: Classmentioning

confidence: 99%

Is Local $H_0$ At Odds With Dark Energy EFT?

Lee,

Colgáin

et al. 2022

Preprint

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“…where H 0 = 100h km sec −1 M pc −1 . Even though this degenerate combination is marginalized in most cases [9,76], recent studies [77][78][79][80] argue that this process may lead to physical information loss, since a physical model with an abrupt transition on the absolute magnitude M at a low redshift z t has the potential to alleviate simultaneously the H 0 and growth tensions [81][82][83][84][85][86][87][88]. Hence, we decide to use this degenerate parameter in the minimization process.…”

Section: Iii1 Pantheon Dataset Fitmentioning

confidence: 99%

Observational constraints on the deceleration parameter in a tilted universe

Asvesta,

Kazantzidis,

Perivolaropoulos

et al. 2022

Preprint

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We study a parametrization of the deceleration parameter in a tilted universe, namely a cosmological model equipped with two families of observers. The first family follows the smooth Hubble flow, while the second are the real observers residing in a typical galaxy inside a bulk flow and moving relative to the smooth Hubble expansion with finite peculiar velocity. We use the compilation of Type Ia Supernovae (SnIa) data, as described in the Pantheon dataset, to find the quality of fit to the data and study the redshift evolution of the deceleration parameter. In so doing, we consider two alternative scenarios, assuming that the bulk-flow observers live in the ΛCDM and in the Einstein-de Sitter universe. We show that a tilted Einstein-de Sitter model can reproduce the recent acceleration history of the universe, without the need of a cosmological constant or dark energy, by simply taking into account linear effects of peculiar motions. By means of a Markov Chain Monte Carlo (MCMC) method, we also constrain the magnitude and the uncertainties of the parameters of the two models. From our statistical analysis, we find that the tilted Einstein-de Sitter model, equipped with one or two additional parameters that describe the assumed large-scale velocity flows, performs similar to the standard ΛCDM paradigm in the context of model selection criteria (Akaike Information Criterion and Bayesian Information Criterion).

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“…The answer to the second question is also positive. Hints for such a transition in the values of dynamical parameters connected to the gravitational constant have recently been pointed out in Cepheid SnIa calibrator data [33,34], in Tully-Fisher data [35] and in solar system history data [36] which indicate an increase of the rate of impactors on the Moon and Earth surfaces by about a factor of 2-3 during the past 100Myrs which correspond to z < 0.008 [37][38][39][40][41][42][43]. Such a transition is also consistent with low redshift galaxy surveys data [44].…”

Section: Introductionmentioning

confidence: 99%