Cosmic Tides

TL;DR

This paper introduces a novel method for reconstructing the 3-D cosmic tidal field using CMB lensing and large scale structure data, enabling precise measurements of gravitational growth and neutrino masses.

Contribution

It presents a new approach to measure the large scale tidal field and gravitational growth without cosmic variance, using small scale filamentary structures and comparing with redshift space data.

Findings

Initial results from simulations show promising accuracy.

Application to SDSS data demonstrates feasibility.

Potential to improve neutrino mass constraints.

Abstract

We apply CMB lensing techniques to large scale structure and solve for the 3-D cosmic tidal field. We use small scale filamentary structures to solve for the large scale tidal shear and gravitational potential. By comparing this to the redshift space density field, one can measure the gravitational growth factor on large scales without cosmic variance. This potentially enables accurate measurements of neutrino masses and reconstruction of radial modes lost in 21 cm intensity mapping, which are essential for CMB and other cross correlations. We relate the tidal fields to the squeezed limit bispectrum, and present initial results from simulations and data from the SDSS.