Fluctuations in the 21cm brightness from cosmic hydrogen at redshifts z & 6 were sourced by the primordial density perturbations from inflation as well as by the radiation from galaxies. We propose a method to separate these components based on the angular dependence of the 21cm fluctuation power spectrum. Peculiar velocities increase the power spectrum by a factor of ∼ 2 compared to density fl...

If the principle of statistical isotropy is valid, then angular power spectrum (APS) cosmic microwave background (CMB) radiation uncorrelated between different multipoles. We propose a novel technique to analyse any possible correlations foreground-cleaned CMB temperature APS measures ( $$C_{\ell }$$ and $${\mathcal {D}}_\ell =({\ell (\ell +1)})/({2\pi })C_\ell $$ ). This motivated by behaviour...

Long-range propagation of sound pulses in the deep ocean is considered. A new method for estimation pulse angular spectrum presented. The based on Husimi transform a wave field and can be realized with short vertical array nondirectional hydrophones. As result, one obtains diagram arrival pattern time–angle plane. applied to model underwater channel Sea Japan. Special attention paid scattering ...