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CG: The integrated Sachs-Wolfe effect in 4D Einstein-Gauss-Bonnet gravity – Ghodsi Yengejeh
April 19, 2022 @ 10:00 am - 10:15 am
A novel 4-dimensional Einstein-Gauss-Bonnet (4D EGB) gravity has been proposed that asserts to bypass Lovelock’s theorem and to result in a non-trivial contribution to the gravitational dynamics in four-dimensional spacetime. Although inconsistencies have been raised for this theory in nonlinear perturbation limits, the results of the consistent 4D EGB model indicate that the background equations and the linear scalar modes are in good agreement with the initial 4D EGB model. We study the integrated Sachs-Wolfe (ISW) effect, as a linear phenomenon, in the 4D EGB model. For this purpose, we calculate the evolution of the gravitational potential and the linear growth factor as a function of redshift for the 4D EGB. We also calculate the ISW-auto power spectrum and the ISW-cross power spectrum as functions of cosmic microwave background multipoles for the 4D EGB model.To do this, we use the strongest constraint on the coupling parameter proposed for the 4D EGB model. Additionally, to calculate the ISW effect for the 4D EGB model, we employ three large-scale structure surveys at different wavelengths. The results exhibit that the ISW effect in the 4D EGB model is higher than the one obtained from the $\Lambda$CDM model. Hence, we show that the 4D EGB model can amplify the amplitude of the ISW power spectrum, which can be considered as a relative advantage of the 4D EGB model comparing the $\Lambda$CDM one. Also, we indicate that the deviation from the $\Lambda$CDM model is directly proportional to the value of the dimensionless coupling parameter $\beta$.