Probing modified gravity with integrated Sachs-Wolfe CMB and galaxy cross-correlations
Abstract
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.
- Publication:
-
Journal of Cosmology and Astroparticle Physics
- Pub Date:
- September 2022
- DOI:
- 10.1088/1475-7516/2022/09/002
- arXiv:
- arXiv:2111.10432
- Bibcode:
- 2022JCAP...09..002K
- Keywords:
-
- dark energy theory;
- integrated Sachs-Wolfe effect;
- modified gravity;
- galaxy surveys;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 25 pages, 5 figures. Published by JCAP