A search for the  variation  of speed of light using galaxy cluster gas mass fraction measurements

Mendonça, I. E. C. R.; Bora, Kamal; Holanda, R. F. L.; Desai, S.; Pereira, S. H.

doi:10.1088/1475-7516/2021/11/034

Cited by 17 publications

(11 citation statements)

References 88 publications

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“…We can compare our results with those in Ref. [76]. Therein, the authors considered only c varying, with a φ c (z) function such as that in our case (I); they obtained c 1 = −0.069 ± 0.056 and c 1 = −0.198±0.052 by using analyses involving gas mass fraction plus H(z) data and gas mass fraction plus SNe Ia observations, respectively.…”

Section: Constraining the Minimal Cpc Modelsupporting

confidence: 70%

“…BD theory and other extensions of the current standard model naturally lead to the concept that fundamental couplings are indeed expected to vary. Some examples of varying physical couplings proposals are studies of variation of the fine-structure constant α [49,50,51,52,53,54,55,56,57], of the Newton's gravitational constant G [58,59,60,61,62,63,64,65], and of the speed of light c [66,67,68,69,70,71,72,73,74,75,76,77,78,79]. The common feature of these works is to take only one of the couplings as a function of the cosmological time while disregarding possible variations of the others.…”

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confidence: 99%

“…[79] used type Ia Supernovae (SNe Ia), BAO, H(z), and CMB data to constrain the variation of c as ∼ 10 −2 , a result confirmed by [72] through a combination of SNe Ia and strong gravitational lensing (SGL). In [76] a new method to test the eventual dependence of the speed of light on the redshift was implemented by combining the measurements of galaxy cluster gas mass fraction (GMF), H(z) and SNe Ia; the analyses indicate negligible variation of the speed of light.…”

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confidence: 99%

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Observational constraints on varying fundamental constants in a minimal CPC model

Cuzinatto¹,

Holanda²,

Pereira³

2022

Preprint

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A minimal model based on the Covariant Physical Couplings (CPC) framework for gravity is proposed. The CPC framework is based on the assumptions of a metric-compatible four-dimensional Riemannian manifold where a covariantly conserved stress-energy tensor acts as source of the field equations which are formally the same as Einstein field equations, but where the couplings {G, c, Λ} are allowed to vary simultaneously. The minimal CPC model takes Λ as a genuine constant while c and G vary in an entangled way that is consistent with Bianchi identity and the aforementioned assumptions. The model is constrained using the most recent galaxy cluster gas mass fraction observational data. Our result indicates that the functions c(z) and G (z) = G 0 (c/c 0 ) 4 are compatible with constant couplings for the two different parameterizations of c = c(z) adopted here.

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Section: Constraining the Minimal Cpc Modelsupporting

confidence: 70%

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confidence: 99%

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confidence: 99%

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Observational constraints on varying fundamental constants in a minimal CPC model

Cuzinatto¹,

Holanda²,

Pereira³

2022

Preprint

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“…Lee [24] did a statistical analysis of a galaxy-scale strong gravitational lensing sample that included stellar velocity dispersion measurement on 161 systems and determined effectively no variation in the speed of light. Mendonca et al [25] obtained negative results in their attempt of determining the variation of 𝑐 using mass fraction measurements in galaxy cluster gas.…”

Section: Introductionmentioning

confidence: 99%

Constraining Coupling Constants’ Variation with Supernovae, Quasars, and GRBs

Gupta

2023

Symmetry

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Dirac, in 1937, proposed the potential variation of coupling constants derived from his large numbers hypothesis. Efforts have continued since then to constrain their variation by various methods, including astrophysical and cosmological observations. We briefly discuss several methods used for the purpose while focusing primarily on the use of supernovae type 1a, quasars, and gamma-ray bursts as cosmological probes for determining cosmological distances. Supernovae type Ia (SNeIa) are considered the best standard candles since their intrinsic luminosity can be determined precisely from their light curves. However, they have only been observed up to about redshift z = 2.3, mostly at z ≤ 1.5. Quasars are the brightest non-transient cosmic sources in the Universe. They have been observed up to z = 7.5. Certain types of quasars can be calibrated well enough for their use as standard candles but with a higher degree of uncertainty in their intrinsic luminosity than SNeIa. Gamma-ray bursts (GRBs) are even brighter than quasars, and they have been observed up to z = 9.4. They are sources of highly transient radiation lasting from tens of milliseconds to several minutes and, in rare cases, a few hours. However, they are even more challenging to calibrate as standard candles than quasars. Both quasars and GRBs use SNeIa for distance calibration. What if the standard candles’ intrinsic luminosities are affected when the coupling constants become dynamic and depend on measured distances? Assuming it to be constant at all cosmic distances leads to the wrong constraint on the data-fitted model parameters. This paper uses our earlier finding that the speed of light c, the gravitational constant G, the Planck constant h, and the Boltzmann constant k vary in such a way that their variation is interrelated as \({G \sim c^{3} \sim h^{3} \sim k^{3/2}}\) with \({\overset{.}{G}/G = 3\overset{.}{c}/c = 3\overset{.}{h}/h = 1.5\overset{.}{k}/k}\) = 3.90(±0.04) × \({10^{-10}}\) yr\({^{-1}}\) and corroborates it with SNeIa, quasars, and GRBs observational data. Additionally, we show that this covarying coupling constant model may be better than the standard \({\Lambda}\)CDM model for using quasars and GRBs as standard candles and predict that the mass of the GRBs scales with z as \({((1+z)^{1/3}-1)}\). Noether’s symmetry on the coupling constants is now transferred effectively to the constant in the function relating to their variation.

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“…Galaxy clusters are the most massive gravitationally collapsed objects in the universe [1][2][3]. Galaxy clusters have proved to be wonderful laboratories for cosmology, galaxy evolution, modified gravity theories, and fundamental Physics [1][2][3][4][5][6]. In the past three decades a large number of galaxy clusters have been discovered through a whole suite of optical, infrared, X-ray and mm-wave surveys.…”

Section: Introductionmentioning

confidence: 99%