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Probing modified gravity with integrated Sachs-Wolfe CMB and galaxy cross-correlations

J. A. Kable, G. Benevento, N. Frusciante, A. de Felice, S. Tsujikawa

We use the cross-correlation power spectrum of the integrated Sachs-Wolfe (ISW) effect in the cosmic microwave background (CMB) temperature anisotropy and galaxy fluctuations to probe the physics of late-time cosmic acceleration. For this purpose, we focus on three models of dark energy that belong to a sub-class of Horndeski theories with the speed of gravity equivalent to that of light: Galileon Ghost Condensate (GGC), Generalized Cubic Covariant Galileon (GCCG), and K-mouflage. In the GGC and GCCG models, the existence of cubic-order scalar self-interactions allows a possibility for realizing negative ISW-galaxy cross-correlations, while the K-mouflage model predicts a positive correlation similar to the Λ-cold-dark-matter (ΛCDM) model. In our analysis, we fix the parameters of each model to their best-fit values derived from a baseline likelihood analysis with observational data from CMB, baryon acoustic oscillations, and supernovae type Ia. Then we fit those best-fit models to the ISW-galaxy cross-correlation power spectrum extracted from a collection of photometric redshift surveys. We find that both GGC and GCCG best-fit models degrade the fit to the ISW-galaxy cross-correlation data compared to ΛCDM best-fit model. This is attributed to the fact that, for their best-fit values constrained from the baseline likelihood, the cubic-order scalar self-interaction gives rise to suppressed ISW tails relative to ΛCDM. The K-mouflage best-fit model is largely degenerate with the ΛCDM best-fit model and has a positively correlated ISW-galaxy power close to that of ΛCDM.

dark energy theory; integrated Sachs-Wolfe effect; modified gravity; galaxy surveys; Astrophysics - Cosmology and Nongalactic Astrophysics

Journal of Cosmology and Astroparticle Physics
Volume 2022, Issue 9
2022 September

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Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia