The Integrated Sachs-Wolfe Effect in 4D Einstein-Gauss-Bonnet Gravity
  A novel 4-dimensional Einstein-Gauss-Bonnet (4D EGB) gravity has been
proposed that asserts to bypass the Lovelock's theorem and to result in a
non-trivial contribution to the gravitational dynamics in four-dimensional
spacetime. In this work, we study the integrated Sachs-Wolfe (ISW) effect 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 model and compare it with the corresponding result obtained from
the $\Lambda$-cold dark matter ($\Lambda$CDM) model. We also calculate the
ISW-auto power spectrum and the ISW-cross power spectrum as functions of cosmic
microwave background (CMB) multipoles for the 4D EGB model and compare those
with the one obtained from the $\Lambda$CDM 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 from 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 $\beta$.
