http://arxiv.org/abs/2012.07373
We propose the intensity mapping of the redshifted HI 21-cm signal from the post-reionization epoch as a cosmological probe of f(R) gravity. We consider the Hu-Sawicki family of f(R) gravity models characterized by a single parameter $f_{,R0}$. The f(R) modification to gravity affects the post-reionization 21-cm power spectrum through the change in the growth rate of density fluctuations. The quantity of interest is the redshift space distortion parameter $\beta_T(k, z)$ which imprints the change. We find that a radio interferometric observation at an observing frequency $710$MHz with a SKA-1-Mid like radio telescope may measure the binned $\beta_T(k)$ at a level of sensitivity to distinguish $f(R)$ models with $\log_{10} |f_{,R0}| > -5$ at a $> 5-\sigma$ level in the k range $ k > 0.4 MPc^{-1}$. We find that using a Fisher matrix analysis the $68\%$ bound obtained on the parameter is $ -5.62 < \log_{10} |f_{,R0}| < – 4.38$ which is competitive with other probes of f(R) gravity. Thus the future observation of the post-reionization HI signal holds the potential to put robust constraints on f(R) gravity models and enrich our understanding of late time cosmic evolution and structure formation.
C. Dash, T. Sarkar and A. Sarkar
Tue, 15 Dec 20
79/136
Comments: Comments are welcome
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