Effective Cross Section of Fuzzy Dark Matter Halos

TL;DR

This paper investigates the effective cross section of fuzzy dark matter halos during collisions, revealing an inverse cubic velocity dependence and highlighting the role of gravitational cooling in dissipative processes.

Contribution

It provides the first numerical analysis of the effective cross section for fuzzy dark matter soliton collisions and offers an analytic interpretation of the velocity dependence.

Findings

Cross section inversely proportional to velocity cubed

Gravitational cooling significantly affects collision dynamics

Estimated spatial offsets in galaxy cluster collisions

Abstract

We numerically study the movement of two colliding fuzzy dark matter solitons without explicit self-interaction and find the effective cross section of dissipative change in velocity. The cross section turns out to be inversely proportional to the velocity cubed, and we present its analytic interpretation. Using the result we roughly estimate spatial offsets during head-on collisions of two fuzzy dark matter halos, which can be related to the spatial offsets between stars and dark matter in collisions of some galaxy clusters. We also show that the gravitational cooling plays an important role during the collisions.