Self-interacting Dark Scalar Spikes around Black Holes via Relativistic Bondi Accretion

Understand

We consider the spike mass density profile in a dark halo by self-consistently solving the relativistic Bondi accretion of dark matter onto a non-spining black hole of mass $M$.

• We assume that the dominant component of the dark matter in the halo is a Standard model gauge-singlet scalar.
• Its mass $m\simeq 10^{-5}{\rm eV}$ and quartic self-coupling $\lambda\lesssim10^{-19}$ are constrained to be compatible with the properties of galactic dark halos.
• In the hydrodynamic limit, we find that the accretion rate is bounded from below, $\dot{M}_{\rm min}=96\pi G^2M^2 m^4/\lambda\hbar^3$.