Boson stars in the centre of galaxies?

TL;DR

This paper explores the gravitational redshift of boson stars with self-interaction, establishing a maximum redshift value and discussing observational prospects, particularly via X-ray spectroscopy.

Contribution

It provides the first detailed analysis of gravitational redshift limits for self-interacting boson stars and assesses their observational detectability.

Findings

Maximum gravitational redshift z_lim ≈ 0.687 for stable boson stars

Boson stars are unlikely to be directly observable

X-ray spectroscopy may be a promising detection method

Abstract

We investigate the possible gravitational redshift values for boson stars with a self-interaction, studying a wide range of possible masses. We find a limiting value of z_lim \simeq 0.687 for stable boson star configurations. We can exclude the direct observation of boson stars. X-ray spectroscopy is perhaps the most interesting possibility.