Dynamical evolutions of $\ell$-boson stars in spherical symmetry

Autor: Alcubierre, Miguel, Barranco, Juan, Bernal, Argelia, Degollado, Juan Carlos, Diez-Tejedor, Alberto, Megevand, Miguel, Núñez, Darío, Sarbach, Olivier
Rok vydání: 2019
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1088/1361-6382/ab4726
Popis: In previous work, we have found new static, spherically symmetric boson star solutions which generalize the standard boson stars by allowing a particular superposition of scalar fields in which each of the fields is characterized by a fixed value of its non-vanishing angular momentum number $\ell$. We call such solutions "$\ell$-boson stars". Here, we perform a series of fully non-linear dynamical simulations of perturbed $\ell$-boson stars in order to study their stability, and the final fate of unstable configurations. We show that for each value of $\ell$, the configuration of maximum mass separates the parameter space into stable and unstable regions. Stable configurations, when perturbed, oscillate around the unperturbed solution and very slowly return to a stationary configuration. Unstable configurations, in contrast, can have three different final states: collapse to a black hole, migration to the stable branch, or explosion (dissipation) to infinity. Just as it happens with $\ell=0$ boson stars, migration to the stable branch or dissipation to infinity depends on the sign of the total binding energy of the star: bound unstable stars collapse to black holes or migrate to the stable branch, whereas unbound unstable stars either collapse to a black hole or explode to infinity. Thus, the parameter $\ell$ allows us to construct a new set of stable configurations. All our simulations are performed in spherical symmetry, leaving a more detailed stability analysis including non-spherical perturbations for future work.
Comment: 17 pages, 8 figure. Updated version with more details on migrating case, typos corrected and references added
Databáze: arXiv
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