Deviations from tidal torque theory: environment dependences on halo angular momentum growth

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

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 485 p. 5244 - 5255

0035-8711

The tidal torque theory (TTT) relates the origin and evolution ofangular momentum with the environment in which dark matter (DM) haloesform. The deviations introduced by late non-linearities are commonlythought as noise in the model. In this work, we analyse a cosmologicalsimulation looking for systematics on these deviations, finding that theclassification of DM haloes according to their angular momentum growthresults in samples with different internal alignment, spin parameterdistribution, and assembly history. Based on this classification, weobtain that low-mass haloes are embedded in denser environments if theyhave acquired angular momentum below the TTT expectations (L haloes),whereas at high masses enhanced clustering is typically associated withhigher angular momentum growths (W haloes). Additionally, we find thatthe low-mass signal has a weak dependence on the direction, whereas thehigh-mass signal is entirely due to the structure perpendicular to theangular momentum. Finally, we study the anisotropy of the matterdistribution around haloes as a function of their mass. We find that theangular momentum direction of W (L) haloes remains statisticallyperpendicular (parallel) to the surrounding structure across the massrange 11<log(M/h^{-1} M_{⊙})< 14, whereas haloes following TTTshow a `spin flip' mass consistent with previously reported values(?5 × 1012 h-1M⊙).Hence, whether the spin flip mass of the deviated samples is highlyshifted or straightly undefined, our results indicate that it isremarkably connected to the haloes angular momentum growth.