Clustering dependence on halo angular momentum growth

LÓPEZ, PABLO; MERCHÁN, MANUEL E; PAZ, DANTE J

La Plata

Workshop; LAPIS 2018: La Plata International School on Astronomy and Geophysics - Cosmology in the era of large surveys; 2018

Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata

Dark matter halos (DM) are the largest virialized structures in the Universe. Their internal dynamics are linked to the history of the galaxies, groups and clusters which form on their potential wells, but also to the large-scale structure of the Universe. Therefore, understanding the dynamical properties of halos becomes a keystone in any cosmological and galaxy formation model. The tidal torque theory (TTT) naturally relates the origin and evolution of angular momentum to the characteristics of the environment in which DM halos formed. Even though TTT is the most accepted model on the current paradigm, its validity range is limited to the early times of structure formation, and its predictions contrast in several aspects with measurements obtained from cosmological simulations on their non-linear stages. In this work, we study and characterize systematic deviations from the TTT model performing a statistical analysis of different DM halo populations in a cosmological simulation. We find that the classification according to their angular momentum growth results in samples with different levels of clustering and radically different distributions of spin parameters. Based on this classification, we find a strong correlation between the angular momentum history and the well known mass dependent alignment between the angular momentum direction and the large-scale structure. Our study suggests that a secondary tidal torque mechanism could be acting during the non-linear stages of halo formation.