Origin and evolution of galactic spin from looking at galaxy pairs

TL;DR

This study investigates how galaxy pairs' spins are correlated and how interactions influence their angular momentum, revealing that close encounters significantly alter the spin parameters of late-type galaxies.

Contribution

It provides evidence of weak spin correlations in galaxy pairs and highlights the impact of interactions on angular momentum redistribution, emphasizing the role of tidal fields and evolutionary processes.

Findings

Weak but significant spin correlation between galaxy pairs

Close interactions reduce the spin parameter of late-type galaxies

Angular momentum redistribution is crucial in galaxy evolution

Abstract

To study if the angular momentum gain for each member of a galaxy pair was the result of tidal torques imprinted by the same tidal field, we search for correlations between the spin in pairs of spiral galaxies identified using the Sloan Digital Sky Survey. We find a weak, but statistically significant correlation between the spin magnitude of neighbouring galaxies. We show that events such as close interactions with neighbours play an important role in the value of the spin for the final configuration, as we find these interactions tend to reduce the value of the $\lambda$ spin parameter of late-type galaxies considerably. This implies that the original tidal field for each pair could have been similar, but the redistribution of angular momentum at later stages of evolution is important