Is Sextans dwarf galaxy in a scalar field dark matter halo?

TL;DR

This study investigates whether the Sextans dwarf galaxy's dark matter halo can be explained by a scalar field dark matter model, constraining particle properties based on stellar substructure longevity.

Contribution

It provides new constraints on scalar field dark matter particle mass and self-interaction parameters using Sextans dwarf galaxy data.

Findings

Scalar field dark matter halos with specific mass ranges explain Sextans' stellar substructure longevity.

Without self-interaction, the scalar field particle mass is constrained between 0.12 and 8 x 10^{-22} eV.

Self-interacting models require unrealistic parameters to fit Sextans data.

Abstract

The Bose-Einstein condensate/scalar field dark matter model, considers that the dark matter is composed by spinless-ultra-light particles which can be described by a scalar field. This model is an alternative model to the $\Lambda$-cold dark matter paradigm, and therefore should be studied at galactic and cosmological scales. Dwarf spheroidal galaxies have been very useful when studying any dark matter theory, because the dark matter dominates their dynamics. In this paper we study the Sextans dwarf spheroidal galaxy, embedded in a scalar field dark matter halo. We explore how the dissolution time-scale of the stellar substructures in Sextans, constrain the mass, and the self-interacting parameter of the scalar field dark matter boson. We find that for masses in the range $(0.12< m_{\phi}<8) \times10^{-22}$~eV, scalar field dark halos without self-interaction would have cores large enough to explain the longevity of the stellar substructures in Sextans, and small enough mass to be compatible with dynamical limits. If the self-interacting parameter is distinct to zero, then the mass of the boson could be as high as $m_{\phi}\approx2\times10^{-21}$~eV, but it would correspond to an unrealistic low mass fot the Sextans dark matter halo . Therefore, the Sextans dwarf galaxy could be embedded in a scalar field/BEC dark matter halo with a preferred self-interacting parameter equal to zero.