On wave dark matter in spiral and barred galaxies

TL;DR

This paper demonstrates that wave dark matter models can naturally produce spiral and barred galaxy structures through interactions with baryonic disks, aligning with observations and challenging assumptions about dark matter distribution inference.

Contribution

It shows how triaxial, rotating dark matter halos in wave dark matter models can generate realistic spiral and barred galaxy patterns without relying on baryonic processes.

Findings

Spiral and barred structures form in simulations with wave dark matter halos.

Bars are commonly produced in these dark matter dominated galaxy models.

Spiral arms and bars can exist in dark matter dominated galaxies with central cores.

Abstract

We recover spiral and barred spiral patterns in disk galaxy simulations with a Wave Dark Matter (WDM) background (also known as Scalar Field Dark Matter (SFDM), Ultra-Light Axion (ULA) dark matter, and Bose-Einstein Condensate (BEC) dark matter). Here we show how the interaction between a baryonic disk and its Dark Matter Halo triggers the formation of spiral structures when the halo is allowed to have a triaxial shape and angular momentum. This is a more realistic picture within the WDM model since a non-spherical rotating halo seems to be more natural. By performing hydrodynamic simulations, along with earlier test particles simulations, we demonstrate another important way in which wave dark matter is consistent with observations. The common existence of bars in these simulations is particularly noteworthy. This may have consequences when trying to obtain information about the dark matter distribution in a galaxy, the mere presence of spiral arms or a bar usually indicates that baryonic matter dominates the central region and therefore observations, like rotation curves, may not tell us what the DM distribution is at the halo center. But here we show that spiral arms and bars can develop in DM dominated galaxies with a central density core without supposing its origin on mechanisms intrinsic to the baryonic matter.