Observational evidence of tidal torque in the primordial Universe

Abstract

Tidal torque theory (TTT) predicts that galaxy angular momenta are imprinted by the early tidal field acting on their proto-structures, which are preserved through cosmic evolution and provide the potentially most precise measurement of the early universe. We test this prediction using the gas component of central massive elliptical galaxies, whose angular momenta respond sensitively to external torques. By comparing the observed gas angular momentum vectors with those predicted from the primordial density field reconstructed by ELUCID for the nearby universe, we conclusively detect a strong direction correlation with a significance of about $7\sigma$. These results provide the first robust observational confirmation of TTT and open a new window for cosmological measurements of neutrino mass and other cosmological parameters.