Quantum Scales of Galaxies from Self-interacting Ultralight Dark Matter

TL;DR

This paper derives characteristic scales for dwarf galaxies within the self-interacting ultralight dark matter model, showing how small self-interactions significantly influence galaxy properties and better explain cosmological observations.

Contribution

It introduces a detailed analysis of galaxy scales in the self-interacting ULDM model, highlighting the impact of self-interactions and connecting these scales to cosmological phenomena.

Findings

Self-interactions alter galaxy scales in the ULDM model.

Self-interacting ULDM better explains cosmological observations.

Characteristic energy scale for self-interacting ULDM is around 10 eV.

Abstract

We derive the characteristic scales for physical quantities of dwarf galaxies, such as mass, size, acceleration, and angular momentum, within the self-interacting ultralight dark matter (ULDM) model. Due to the small mass of ULDM, even minor self-interactions can drastically alter these scales in the Thomas-Fermi limit. We suggest that these characteristic scales are connected to mysteries of observed galaxies. Oscillation of ULDM field can explain the current cosmological density of dark matter. Many cosmological constraints suggest that the energy scale $\tilde{m}$ for self-interacting ULDM is typically of the order $10~eV$, whereas the mass $m$ for the non-interacting case is around $10^{-21}~eV$. Self-interacting ULDM provides the better explanation for cosmological observations than the non-interacting case.