López Pablo
Argentina – Instituto de Astronomía Teórica y Experimental (IATE)
An anisotropic extension of tidal torque theoryAlthough tidal torque theory (TTT) is currently the most accepted model to describe the origin and evolution of angular momentum (AM) of dark matter halos and galaxies during the linear stage, numerical simulations show that the spin of proto-halos is reoriented on average about 30° with respect to its predictions. In this work we present a novel implementation that introduces an anisotropic scaling factor to the standard TTT equations. Thereby, the AM orientation is expected to change in time, even during the linear regime. The amplitude and direction of this change depend exclusively on the gravitational tidal field around the forming proto-halos. Our results significantly improve the predictions for the AM direction up to the time of protohalo collapse and, in some cases, even up to the present time. The relation this model establishes between the AM reorientation and the direction of the surrounding tidal field could provide insight into known features of the spin-cosmic web alignment such as the transition mass.