A Numerical Study of Solitonic Boson Stars in General Relativity

Abstract

In the wake of the recent detection of gravitational wave signal GW150914, we investigate whether GW150914 could have been produced by something other than a binary black hole system. Our proposed candidate is a binary system of solitonic boson stars. The choice of solitonic boson stars is due mainly to the structural properties of their ground states, as solitonic boson stars are capable of forming very compact thin-wall ground states which would likely correctly mimic the gravitational signature of the plunge/merger phase of the binary system lifecycle. On the other hand, the question of whether solitonic boson stars could also mimic the gravitational signature of the subsequent ringdown phase is still open. Since there is no hope of replicating the signature if these thin-wall ground states are not stable with respect to small perturbations, our ultimate goal is to study the stability properties of these thin-wall ground states numerically. Pursuing this goal, we have successfully developed numerical methods for both the computation of ground states of boson stars and the simulation of boson stars exposed to a small perturbation from a real scalar field. Our methods can compute the desired thin-wall ground states of solitonic boson stars, as well as produce a simulation of a perturbed ground state of a mini-boson star. We provide a thorough look at the implementation details of these methods and present our current computational results.