Dwarf galaxies in multistate Scalar Field Dark Matter haloes

TL;DR

This paper demonstrates that including excited states in multistate Scalar Field Dark Matter haloes improves the modeling of velocity dispersions in dwarf galaxies, aligning better with observations than pure Bose-Einstein condensate models.

Contribution

It introduces a multistate scalar field dark matter framework that accounts for excited states, providing a more consistent description of dwarf and large galaxies.

Findings

Excited states significantly influence dwarf spheroidal galaxy velocity dispersions.

Multistate models better fit observational data than pure condensate models.

Framework unifies the description of different galaxy sizes within scalar field dark matter.

Abstract

We analyse the velocity dispersion for eight of the Milky Way dwarf spheroidal satellites in the context of finite temperature scalar field dark mater. In this model the finite temperature allows the scalar field to be in configurations that possess excited states, a feature that has proved to be necessary in order to explain the asymptotic rotational velocities found in low surface brightness (LSB) galaxies. In this work we show that excited states are not only important in large galaxies but also have visible effects in dwarf spheroidals. Additionally, we stress that contrary to previous works where the scalar field dark matter haloes are consider to be purely Bose-Einstein condensates, the inclusion of excited states in these halo configurations provides a consistent framework capable of describing LSBs and dwarf galaxies of different sizes without arriving to contradictions within the scalar field dark matter model. Using this new framework we find that the addition of excited states accounts very well for the raise in the velocity dispersion in Milky Way dwarf spheroidal galaxies improving the fit compared to the one obtained assuming all the DM to be in the form of a Bose Einstein Condensate.