Is it no Longer Necessary to Test Cosmologies with Type Ia Supernovae?

Vishwakarma, R. G.; Narlikar, Jayant V.

doi:10.3390/universe4060073

Cited by 9 publications

(10 citation statements)

References 23 publications

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“…However, since the discovery of the microwave background radiation by Penzias and Wilson in 1964 [2], the acceptable explanation for the redshift by mainstream cosmologist has steadily shifted in favour of the big-bang expansion of the universe, and today alternative approaches for explaining the redshift are not acceptable by most cosmologists. The situation has been most succinctly expressed by Vishwakarma and Narlikar in a recent paper [3] as follows: "… a recent trend in the analysis of SNeIa data departs from the standard practice of executing a quantitative assessment of a cosmological theory-the expected primary goal of the observations [4,5]. Instead of using the data to directly test the considered model, the new procedure tacitly assumes that the model gives a good fit to the data, and limits itself to estimating the confidence intervals for the parameters of the model and their internal errors.…”

Section: Introductionmentioning

confidence: 99%

SNe Ia Redshift in a Nonadiabatic Universe

Gupta¹

2018

Universe

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Absract: By relaxing the constraint of adiabatic universe used in most cosmological models, we have shown that the new approach provides a better fit to the supernovae Ia redshift data with a single parameter, the Hubble constant 0 , than the standard ΛCDM model with two parameters, 0 and the cosmological constant Λ related density Ω Λ . The new approach is compliant with the cosmological principle. It yields the 0 = 68.28 (±0.53) km s -1 Mpc -1 with an analytical value of the deceleration parameter 0 = −0.4. The analysis presented is for a matter only, flat universe. The cosmological constant Λ may thus be considered as a manifestation of a non-adiabatic universe that is treated as an adiabatic universe.

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Section: Introductionmentioning

confidence: 99%

SNe Ia Redshift in a Nonadiabatic Universe

Gupta¹

2018

Universe

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“…It should be mentioned that following Vishwakarma and Narlikar [38] we have preferred to use Pearson's χ 2 weighted least square fit approach of data analysis through the χ 2 probability comparison of various models rather than the Bayesian approach.…”

Section: Resultsmentioning

confidence: 99%

Determining Evolution of Cosmological Constant, Gravitational Constant and Speed of Light Using Nonadiabatic Cosmological Model and LLR Findings

Gupta¹

2019

Galaxies

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We have shown that the Hubble constant H0 embodies the information about the evolutionary nature of the cosmological constant Λ, gravitational constant G, and the speed of light c. We have derived expressions for the time evolution of G/c2 (≡K) and dark energy density εΛ related to Λ by explicitly incorporating the nonadiabatic nature of the universe in the Friedmann equation. We have found (dK/dt)/K = 1.8H0 and, for redshift z, εΛ,z/εΛ,0 = 0.4+0.61+z-1.52. Since the two expressions are related, we believe that the time variation of K (and therefore that of G and c) is manifested as dark energy in cosmological models. When we include the null finding of the lunar laser ranging (LLR) for (dG/dt)/G and relax the constraint that c is constant in LLR measurements, we get (dG/dt)/G = 5.4H0 and (dc/dt)/c = 1.8H0. Further, when we adapt the standard ΛCDM model for the z dependency of εΛ rather than it being a constant, we obtain surprisingly good results fitting the SNe Ia redshift z vs distance modulus µ data. An even more significant finding is that the new ΛCDM model, when parameterized with low redshift data set (z < 0.5), yields a significantly better fit to the data sets at high redshifts (z > 0.5) than the standard ΛCDM model. Thus, the new model may be considered robust and reliable enough for predicting distances of radiation emitting extragalactic redshift sources for which luminosity distance measurement may be difficult, unreliable, or no longer possible.

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“…Estimates of SNe Ia distances typically rely on nearby Cepheid variable star distances which are still being adjusted [13,14]. In addition, the methods used for evaluations of the SNe Ia data and claims therefrom have been repeatedly questioned [15,16]. An independent method for estimating H 0 has recently been published based on the characteristics of selected red giant stars [17,18].…”

Section: Introductionmentioning

confidence: 99%

The Tension over the Hubble-Lemaitre Constant

Smith¹,

Öztaş²

2020

Cosmology 2020 - The Current State [Working Title]

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Astronomers continue the search for better a Hubble-Lemaitre constant, H 0 , value and other cosmological parameters describing our expanding Universe. One investigative school uses 'standard candles' to estimate distances correlated with galactic redshifts, which are then used to calculate H 0 and other parameters. These distance values rely on measurements of Cepheid variable stars, supernovae types Ia and II or HII galaxies/giant extra-galactic HII regions (GEHR) or the tip of red giant star branch to establish a distance 'ladder'. We describe some common pitfalls of employing log-transformed HII/GEHR and SNe Ia data rather than actual distances and suggest better analytical methods than those commonly used. We also show that results using HII and GEHR data are more meaningful when low quality data are discarded. We then test six important cosmological models using HII/GEHR data but produce no clear winner. Groups utilising gravitational waves and others measuring signals from the cosmic microwave background are now at odds, 'tension', with those using the SNe Ia and HII data over Hubble-Lemaitre constant values. We suggest a straightforward remedy for this tension.

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Is it no Longer Necessary to Test Cosmologies with Type Ia Supernovae?

Cited by 9 publications

References 23 publications

SNe Ia Redshift in a Nonadiabatic Universe

SNe Ia Redshift in a Nonadiabatic Universe

Determining Evolution of Cosmological Constant, Gravitational Constant and Speed of Light Using Nonadiabatic Cosmological Model and LLR Findings

The Tension over the Hubble-Lemaitre Constant

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