Simulations of solitonic core mergers in ultra-light axion dark matter cosmologies

Using three-dimensional simulations, we study the dynamics and final structure of merging solitonic cores predicted to form in ultra-light axion dark matter halos. The classical, Newtonian equations of motion of a self-gravitating scalar field are described by the Schr\"odinger-Poisson equation...

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Bibliographic Details
Published in:arXiv.org 2017-01
Main Authors: Schwabe, Bodo, Niemeyer, Jens C, Engels, Jan F
Format: Article
Language:English
Subjects:
Angular momentum
Core loss
Dark matter
Dynamic structural analysis
Ellipsoids
Equations of motion
Galactic halos
Gravitation
Mass ratios
Mathematical analysis
Rotating spheres
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Summary:Using three-dimensional simulations, we study the dynamics and final structure of merging solitonic cores predicted to form in ultra-light axion dark matter halos. The classical, Newtonian equations of motion of a self-gravitating scalar field are described by the Schr\"odinger-Poisson equations. We investigate mergers of ground state (boson star) configurations with varying mass ratios, relative phases, orbital angular momenta and initial separation with the primary goal to understand the mass loss of the emerging core by gravitational cooling. Previous results showing that the final density profiles have solitonic cores and NFW-like tails are confirmed. In binary mergers, the final core mass does not depend on initial phase difference or angular momentum and only depends on mass ratio, total initial mass, and total energy of the system. For non-zero angular momenta, the otherwise spherical cores become rotating ellipsoids. The results for mergers of multiple cores are qualitatively identical.
ISSN:2331-8422
DOI:10.48550/arxiv.1606.05151