Compact (A)dS boson stars and shells

Abstract

We present compact $Q$-balls in an (anti--)de Sitter background in $D$ dimensions, obtained with a V-shaped potential of the scalar field. Beyond critical values of the cosmological constant ${\stackrel{^}{\ensuremath{\Lambda}}}_{\mathrm{cr}}(D)$ compact $Q$-shells arise. By including the gravitational backreaction, we obtain boson stars and boson shells with (anti--)de Sitter asymptotics. We analyze the physical properties of these solutions and determine their domain of existence. In four dimensions we address some astrophysical aspects.