Gravitational Cooling of Self‐gravitating Bose Condensates

Abstract

Equilibrium configurations for a self-gravitating scalar field with self-interaction are constructed. The corresponding Schrödinger-Poisson (SP) system is solved using finite differences assuming spherical symmetry. It is shown that equilibrium configurations of the SP system are late-time attractor solutions for initially quite arbitrary density profiles, which relax and virialize through the emission of scalar field bursts; a process dubbed gravitational cooling. Among other potential applications, these results indicate that scalar field dark matter models (in its different flavors) tolerate the introduction of a self-interaction term in the SP equations. This study can be useful in exploring models in which dark matter in galaxies is not point-like.

Scalar field dark matter: Head-on interaction between two structures

“…pl /m as found also for fully relativistic boson star solutions [19,22]; this implies that the value m sets the physical lenght and time scale of the configuraions evolved. This mass, together with the scaling relations of the Schrödinger-Poisson system [18,20,23] are the basics for transforming back to physical units the system of interest (see an exmple below).…”

“…Details about the construction of initial data for spherically symmetric equilibrium configurations can be found in [19,20,23]. Here we briefly mention the procedure used in our binary case.…”

“…Thus, at the moment the pieces of the model seem to match both, at cosmic and at local scales. In fact, recently in [19] it was shown that the scalar field gravitational collapse tolerates the introduction of a self-interaction term in the potential, which makes the model to seem quite like a self-gravitating Bose-Condensate. In [20] we showed that spherically symmetric equilibrium solutions of the SP system are stable against non-spherical perturbations, and moreover, such configurations played the role of late-time attractors for initially quite general ax-isymmetric initial density profiles.…”

A Review on the Scalar Field/Bose-Einstein Condensate Dark Matter Model

“…[118,119] reviewed the key properties that may arise from the bosonic nature of SFDM models. On the other hand, several authors have numerically studied the formation, collapse and viralization of SFDM/BEC halos as well as the dynamics of the SFDM around black holes [46,47,48,124,25,39,30,13]. In [2], Alcubierre et al found that the critical mass for collapse of the SF is of the order of a Milky Way-sized halo mass.…”

“…In addition, many numerical simulations have been performed to study the gravitational collapse of the SFDM/BEC model [14,15,28,46,47,48,38,88,89,13]. [24,25] found an approximate analytical expression and numerical solutions of the mass-radius relation of SFDM/BEC halos.…”