Abstract:
The Integrated Sachs-Wolfe effect is a Cold Microwave Background observable particularly sensitive to the change in cosmological eras dominated by different mat- ter components. Its temperature power spectrum is a strong evidence of the late accelerated expansion of the Universe which is independent of local measurements. Concomitantly, Modified Gravity theories try to explain the accelerated expansion of the Universe without resorting to the existenc of a cosmological constant or exotic equations of state for the material components of the Universe. In this background, the present work looks at how the ISW effect can help in distinguishing the con- cordance model ΛCDM and Modified Gravity models, particularly f (R) theories like the one of Starobinsky. We analyse how cosmological observables linked to the growth of perturbations and structure formation are affected by the change in cos- mological models in different theories, and we observe how the ISW power spectrum is changed by the modification of f (R) theory in relation to the ΛCDM model.
