Interference of Dark Matter Solitons and Galactic Offsets

TL;DR

This paper uses numerical simulations to explore how dark matter solitons could cause observable offsets between dark and ordinary matter in galaxies, supporting the idea that dark matter may be a Bose-Einstein condensate of ultralight axions.

Contribution

It demonstrates that solitonic dark matter cores can explain galactic offsets, providing a novel wave-based interpretation supported by simulations with specific axion mass parameters.

Findings

Simulations show dark matter solitons can cause galactic offsets.

Offsets are consistent with observations of Abell 3827.

Future observations can test this wave dark matter model.

Abstract

By performing numerical simulations, we discuss the collisional dynamics of stable solitary waves in the Schrodinger-Poisson equation. In the framework of a model in which part or all of dark matter is a Bose-Einstein condensate of ultralight axions, we show that these dynamics can naturally account for the relative displacement between dark and ordinary matter in the galactic cluster Abell 3827, whose recent observation is the first empirical evidence of dark matter interactions beyond gravity. The essential assumption is the existence of solitonic galactic cores in the kiloparsec scale. For this reason, we present simulations with a benchmark value of the axion mass $m_a = 2 \times 10^{-24}$ eV, which is somewhat lower than the one preferred for cosmological structure formation if the field is all of dark matter ($m_a \approx 10^{-22}$eV). We argue that future observations might bear out or falsify this coherent wave interpretation of dark matter offsets.