growth rate of cosmic structures in the local universe with the ALFALFA survey | Monthly notices from the Royal Astronomical Society

We study the growth rate of structures in the local Universe. For this, we use as a cosmological tracer the extra-galactic sources of the HI line from the Arecibo Legacy Fast ALFA (ALFALFA) survey to obtain a measurement of the normalized growth rate parameter, Fσ₈, considered a powerful tool for constraining alternative models of gravity. For these analyzes, we calculate the speed of the local group due to the distribution of the structures of matter in the ALFALFA catalog and compare it with the speed of the local group with respect to the microwave cosmic background frame to obtain the parameter of speed scale, β. Using Monte Carlo realizations and lognormal simulations, our methodology quantifies the errors introduced by the firing noise and the partial sky coverage of the analyzed data. The measurement of the speed scale parameter β, and the calculation of the material fluctuation of the cosmological tracer, | $ sigma _ {8} ^ { text {tr}} $ | ⁠, lead us to Fσ₈ = 0.46 ± 0.06 at | $ bar {z} = $ 0.013 | ⁠, in good agreement (at level 1σ) with the expected value in the ΛCDM concordance model. In addition, our analyzes of the ALFALFA sample also provide a measure of the growth rate of structures. F= 0.56 ± 0.07, at | $ bar {z} = $ 0.013 | ⁠.