Eccentric black hole mergers via three-body interactions in young, globular, and nuclear star clusters

• Verfasst von: Dall’Amico, Marco [VerfasserIn]
• Verfasst von: Mapelli, Michela [VerfasserIn]
• Verfasst von: Torniamenti, Stefano [VerfasserIn]
• Verfasst von: Sedda, Manuel Arca [VerfasserIn]
• Titel: Eccentric black hole mergers via three-body interactions in young, globular, and nuclear star clusters
• Verf.angabe: Marco Dall’Amico, Michela Mapelli, Stefano Torniamenti, and Manuel Arca Sedda
• E-Jahr: 2024
• Jahr: 18 March 2024
• Umfang: 14 S.
• Illustrationen: Illustrationen
• Fussnoten: Gesehen am 15.07.2024
• Titel Quelle: Enthalten in: Astronomy and astrophysics
• Ort Quelle: Les Ulis : EDP Sciences, 1969
• Jahr Quelle: 2024
• Band/Heft Quelle: 683(2024) vom: März, Artikel-ID A186, Seite 1-14
• ISSN Quelle: 1432-0746
• DOI: doi:10.1051/0004-6361/202348745
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1895395690

Abstract

Eccentric mergers are a signature of the dynamical formation channel of binary black holes (BBHs) in dense stellar environments and hierarchical triple systems. Here, we investigate the formation of eccentric mergers via binary-single interactions by means of 2.5 × 105 direct N-body simulations. Our simulations include post-Newtonian terms up to the 2.5th order and model the typical environment of young (YSCs), globular (GCs), and nuclear star clusters (NSCs). Around 0.6% (1%) of our mergers in NSCs (GCs) have an eccentricity >0.1 when the emitted gravitational wave frequency is 10 Hz in the source frame, while in YSCs this fraction rises to 1.6%. Approximately ∼63% of these mergers are produced by chaotic, resonant interactions where temporary binaries are continuously formed and destroyed, while ∼31% arise from an almost direct collision of two black holes (BHs). Lastly, ∼6% of these eccentric mergers occur in temporary hierarchical triples. We find that binaries undergoing a flyby generally develop smaller tilt angles with respect to exchanges. This result challenges the idea that perfectly isotropic spin orientations are produced by dynamics. The environment dramatically affects BH retention: 0%, 3.1%, and 19.9% of all the remnant BHs remain in YSCs, GCs, and NSCs, respectively. The fraction of massive BHs also depends on the host cluster properties, with pair-instability (60 ≤ MBH/M ≤ 100) and intermediate-mass (MBH ≥ 100 M ) BHs accounting for approximately ∼44% and 1.6% of the mergers in YSCs, ∼33% and 0.7% in GCs, and ∼28% and 0.4% in NSCs, respectively.