Parasitic black holes: the swallowing of a fuzzy dark matter soliton

TL;DR

This paper investigates how supermassive black holes can be accreted by fuzzy dark matter solitons, revealing stages of the process and estimating their lifetimes, which can be sufficient for survival until today.

Contribution

It provides a detailed numerical relativity analysis of black hole and boson star interactions within fuzzy dark matter models, identifying stages and lifetime estimates.

Findings

Identified three stages of black hole accretion by boson stars.

Derived an expression for the lifetime of boson stars with black holes.

Found that these objects can survive until the present time.

Abstract

Fuzzy dark matter is an exciting alternative to the standard cold dark matter paradigm, reproducing its large scale predictions, while solving most of the existing tension with small scale observations. These models postulate that dark matter is constituted by light bosons and predict the condensation of a solitonic core -- also known as boson star, supported by wave pressure -- at the center of halos. However, solitons which host a \emph{parasitic} supermassive black hole are doomed to be swallowed by their guest. It is thus crucial to understand in detail the accretion process. In this work, we use numerical relativity to self-consistently solve the problem of accretion of a boson star by a central black hole, in spherical symmetry. We identify three stages in the process, a {\it boson-quake}, a {\it catastrophic stage} and a linear phase, as well as a general accurate expression for the lifetime of a boson star with an endoparasitic black hole. Lifetimes of these objects can be large enough to allow them to survive until the present time.