# Dark Disk Substructure and Superfluid Dark Matter

## TL;DR

This paper explores disk-like solutions of condensate dark matter models, analyzing their stability, astrophysical implications, and potential signals in gravitational lensing to distinguish dark matter types.

## Contribution

It introduces novel, highly compressed disk-like solutions for axion Bose-Einstein condensates and superfluids, and examines their stability and observational signatures.

## Key findings

- Disk-like solutions are linearly stable.
- Potential gravitational lensing signals identified.
- Implications for dark matter substructure and detection.

## Abstract

Dark matter substructure has the potential to discriminate between broad classes of dark matter models. With this in mind, we construct novel solutions to the equations of motion governing condensate dark matter candidates, namely axion Bose-Einstein condensates and superfluids. These solutions are highly compressed along one axis and thus have a disk-like geometry. We discuss linear stability of these solutions, consider the astrophysical implications as a large-scale dark disk or as small scale substructure, and find a characteristic signal in strong gravitational lensing. This adds to the growing body of work that indicates that the morphology of dark matter substructure is a powerful probe of the nature of dark matter.