Cosmic tidal reconstruction

Understand

The gravitational coupling of a long-wavelength tidal field with small-scale density fluctuations leads to anisotropic distortions of the locally measured small-scale matter correlation function.

• Since the local correlation function is known to be statistically isotropic in the absence of such tidal interactions, the tidal distortions can be used to reconstruct the long-wavelength tidal field and large-scale density field in analogy with the cosmic microwave background lensing reconstruction.
• In this paper we present the theoretical framework of cosmic tidal reconstruction and test the reconstruction in numerical simulations.
• We find that the density field on large scales can be reconstructed with good accuracy and the cross-correlation coefficient between the reconstructed density field and the original density field is greater than 0.9 on large scales $(k\lesssim0.1\ h/\mathrm{Mpc})$, with the filter scale $\sim1.25\ \mathrm{Mpc}/h$.