Constraints on variation of fine structure constant from joint SPT-SZ and XMM-Newton observations

Bora, Kamal; Desai, Shantanu

doi:10.48550/arxiv.2008.10541

Cited by 4 publications

(5 citation statements)

References 52 publications

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“…We assume that the intra-cluster medium is an ideal gas, with its equation of state given by P = n e k B T , where P refers the pressure of the intra-cluster gas. The relation between the integrated Compton parameter over the solid angle (Y SZ ) and the angular diameter distance to the cluster (D A ) is given by [64]:…”

Section: Methodsmentioning

confidence: 99%

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A test of cosmic distance duality relation using SPT-SZ galaxy clusters, Type Ia supernovae, and cosmic chronometers

Bora

Desai²

2021

J. Cosmol. Astropart. Phys.

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We carry out a test of the cosmic distance duality relation using a sample of 52 SPT-SZ clusters, along with X-ray measurements from XMM-Newton. To carry out this test, we need an estimate of the luminosity distance (DL) at the redshift of the cluster. For this purpose, we use three independent methods: directly using DL from the closest Type Ia Supernovae from the Union 2.1 sample, non-parametric reconstruction of DL using the same Union 2.1 sample, and finally using H(z) measurements from cosmic chronometers and reconstructing DL using Gaussian Process regression. We use four different functions to characterize the deviations from CDDR. All our results for these (4 × 3) analyses are consistent with CDDR to within 1σ.

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Section: Methodsmentioning

confidence: 99%

“…(A.2), P (r) refers to the pressure profile. To do the conversion, we have used the Universal Pressure Profile (UPP) for P (r) [99], similar to our previous work [64].…”

Section: A Conversion From Cylindrical To Spherical Y Szmentioning

confidence: 99%

A test of cosmic distance duality relation using SPT-SZ galaxy clusters, Type Ia supernovae, and cosmic chronometers

Bora

Desai²

2021

J. Cosmol. Astropart. Phys.

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“…In fact, recent studies of extensions of the general relativity theory proposes that fundamental couplings of physics are expected to vary. As a few examples we mention models involving variations of the fine-structure constant α [54,55,56,57,58,59,60,61,62], models admitting variation of the Newton's gravitational constant G [63,64,65,66,67,68,69,70], and models addressing the variation of the speed of light c [71,72,73,74,75,76,77,78,79,80,21,81,82,83,84,85,29,86]. The main feature of these works is the fact that they consider only one of the aforementioned couplings as a function of the time, while disregarding possible variations of the others.…”

Section: Introductionmentioning

confidence: 99%

Testing a varying-$Λ$ model for dark energy within CPC framework

Cuzinatto,

Gupta,

Holanda

et al. 2022

Preprint

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The CPC (Covariant Physical Couplings) framework is a modified gravity set up assuming Einstein Field Equations wherein the quantities {G, c, Λ} are promoted to spacetime functions. Bianchi identity and the requirement of stress-energy tensor conservation entangle the possible variations of the couplings {G, c, Λ}, which are forced to co-vary as dictated by the General Constraint (GC). In this paper we explore a cosmological model wherein G, c and Λ are functions of the redshift respecting the GC of the CPC framework. We assume a linear parameterization of Λ in terms of the scale factor a. We use the ansatz Ġ/G = σ ( ċ/c) with σ = constant to deduce the functional forms of c = c(z) and G = G(z). We show that this varying-{G, c, Λ} model fits SNe Ia data and H(z) data with σ = 3. The model parameters can be constrained to describe dark energy at the background level.

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“…The dependency of the ratio of these two quantities on the fine structure constant is given by ∝ α 3.5 and thus it can be used to investigate the time variation of α [90][91][92][93][94][95]. The effects of time-varying α on other cosmological observables like strong lensing (SL), white dwarfs (WDs), and etc have also been probed [96][97][98][99].…”

Section: Introductionmentioning

confidence: 99%

The minimally extended Varying Speed of Light (meVSL)

Lee

2020

Preprint

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Even though there have been the various varying speed of light (VSL) cosmology models, they remain out of the mainstream because of their possible violation of physics laws built into fundamental physics. In order to be the VSL as a viable theory, it should inherit the success of special relativity including Maxwell equations and thermodynamics at least. Thus, we adopt that the speed of light, c varies for the cosmic time not for the local time, i.e., c[z] where z is the cosmological redshift.When one describes the background FLRW universe, one can define the constanttime hypersurface by using physical quantities such as temperature, density, and c.It is because they evolve in time, and the homogeneity of the Universe demands that they must equal at the equal cosmic time. The variation of c accompanies the joint variations of all related physical constants in order to satisfy the Lorentz invariance, thermodynamics, and Bianchi identity. We call this VSL model as a "minimally extended VSL (meVSL)". We derive cosmological observables of meVSL and obtain the constraints on the variation of c by using the current observations. Interestingly, z and all geometrical distances except the luminosity distance of meVSL are the same as those of general relativity. However, the Hubble parameter of meVSL is rescaled as H = (1 + z) −b/4 H (GR) which might be used as a solution for the tension of the Hubble parameter measurements. In this manuscript, we provide the main effects of meVSL on various cosmological observations including BBN, CMB, SZE, BAO, SNe, GWs, H, SL, and ∆α.

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Constraints on variation of fine structure constant from joint SPT-SZ and XMM-Newton observations

Cited by 4 publications

References 52 publications

A test of cosmic distance duality relation using SPT-SZ galaxy clusters, Type Ia supernovae, and cosmic chronometers

A test of cosmic distance duality relation using SPT-SZ galaxy clusters, Type Ia supernovae, and cosmic chronometers

Testing a varying-$Λ$ model for dark energy within CPC framework

The minimally extended Varying Speed of Light (meVSL)

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