Frequentist model comparison tests of sinusoidal variations in measurements of Newton's gravitational constant

Desai, S.

doi:10.1209/0295-5075/115/20006

Cited by 19 publications

(23 citation statements)

References 12 publications

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“…If the two models are nested, then from Wilk's theorem [22], the difference in χ 2 between the two models satisfies a χ 2 distribution with degrees of freedom equal to the difference in the number of free parameters for the two hypotheses [18]. Frequentist tests have been used a lot in astrophysics, from testing claims of sinusoidal variations in G as a function of time [23] to classification of GRBs [24].…”

Section: Introduction To Model Comparison Techniquesmentioning

confidence: 99%

Statistical significance of spectral lag transition in GRB 160625B

Ganguly

Desai

2017

Astroparticle Physics

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Recently Wei et al [1] have found evidence for a transition from positive time lags to negative time lags in the spectral lag data of GRB 160625B. They have fit these observed lags to a sum of two components: an assumed functional form for intrinsic time lag due to astrophysical mechanisms and an energy-dependent speed of light due to quadratic and linear Lorentz invariance violation (LIV) models. Here, we examine the statistical significance of the evidence for a transition to negative time lags. Such a transition, even if present in GRB 160625B, cannot be due to an energy dependent speed of light as this would contradict previous limits by some 3-4 orders of magnitude, and must therefore be of intrinsic astrophysical origin. We use three different model comparison techniques: a frequentist test and two information based criteria (AIC and BIC). From the frequentist model comparison test, we find that the evidence for transition in the spectral lag data is favored at 3.05σ and 3.74σ for the linear and quadratic models respectively. We find that ∆AIC and ∆BIC have values 10 for the spectral lag transition that was motivated as being due to quadratic Lorentz invariance violating model pointing to "decisive evidence". We note however that none of the three models (including the model of intrinsic astrophysical emission) provide a good fit to the data.

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Section: Introduction To Model Comparison Techniquesmentioning

confidence: 99%

Statistical significance of spectral lag transition in GRB 160625B

Ganguly

Desai

2017

Astroparticle Physics

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“…Both of these information-criterion based model comparison techniques have been applied to a variety of problems in astrophysics and particle physics, including in the classification of GRBs (Shi et al 2012;Desai & Liu 2016;Desai 2016;Kulkarni & Desai 2017a;Ganguly & Desai 2017;Kulkarni & Desai 2017b) and references therein.…”

Section: Introductionmentioning

confidence: 99%

Two Dimensional Clustering of Gamma-Ray Bursts using durations and hardness

Bhave,

Kulkarni,

Desai

et al. 2017

Preprint

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Gamma-Ray Bursts (GRBs) have been conventionally bifurcated into two distinct categories: "short" and "long" with durations less than and greater than two seconds respectively. However, there is a lot of literature (although with conflicting results) regarding the existence of a third intermediate class. To investigate this issue, we extend a recent study by Kulkarni & Desai 2017a on classification of GRBs to two dimensions by incorporating the GRB hardness in addition to the observed durations. We carry out this unified analysis on GRB datasets from four detectors, viz. BATSE, RHESSI, Swift (observed and intrinsic frame), and Fermi-GBM. We consider the duration and hardness features in log-scale for each of these datasets and determine the best-fit parameters using Gaussian Mixture Model. This is followed by information theoretic criterion (AIC and BIC) to determine if a threecomponent fit is favored compared to a two-component one or vice-versa. For BATSE, we find that both AIC and BIC show preference for three components with decisive significance. For Fermi and RHESSI, both AIC and BIC show preference for two components, although the significance is marginal from AIC, but decisive using BIC. For Swift dataset in both the observed and rest frame, we find that three components are favored according to AIC with decisive significance, and two Aishwarya Bhave

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“…This connection could be made by using Equation (3) (3), having a constant plus a no sinusoidal temporal variable, correlated well with the opinion of Pitkin [6] and Desai [7].…”

Section: Sun-earth Direction and The Direction Of Apparatus Axis Of Rmentioning

confidence: 61%

Toward a Common Ground for Gravity and Optics

Parra¹

2018

JAMP

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A long enough period of observation of the Sun's gravitational dragging effects by using a modified Cavendish's balance output of experimental evidence shows new patterns. Those patterns can be explained assuming that the Sun has a torus with rotation, precession, and nutation. This purpose of this paper is to introduce the frequencies of all those movements. The torus's rotational period can be used to explain the Sun's magnetic pole reversal. Utilizing a modified Cavendish's balance showed an output of dragging forces stronger than the attraction between the gravitational masses. This tool afforded this research a new experimental possibility to a more precise determination of the Universal Gravitational Constant Big G. Moreover, the dragging forces directly affect any volume of mass, which includes the atmosphere. This paper shows a correlation between the Sun's dragging peaks and density of the air squared. The aforementioned correlation and the inverse cubic relation with the distance to the Sun are common for the dragging and tide forces providing the possibility that tidal forces are also a gravitational dragging consequence. The last 2017 total Solar eclipse created a new temporal reaction on the modified Cavendish's balance. That temporal pattern looks as the spatial pattern created by an opaque disk. This similarity allows the researcher to calculate that the dragging forces are transmitted by photons with spatial periodicity of value λ = 6.1 km.

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Frequentist model comparison tests of sinusoidal variations in measurements of Newton's gravitational constant

Cited by 19 publications

References 12 publications

Statistical significance of spectral lag transition in GRB 160625B

Statistical significance of spectral lag transition in GRB 160625B

Two Dimensional Clustering of Gamma-Ray Bursts using durations and hardness

Toward a Common Ground for Gravity and Optics

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