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arXiv · 2604.15240

Boson star-black hole binaries: initial data and head-on collisions

Zhuan Ning
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Abstract

We present a numerical-relativity study of comparable-mass boson star-black hole (BS-BH) head-on collisions, focusing on both initial-data construction and gravitational-wave (GW) phenomenology. We show that plain superposition can strongly perturb the BS core, leading to large constraint violations and unphysical radial oscillations. To remedy this problem, we introduce a one-body conformal-factor correction and find that it substantially suppresses these artifacts. Using the improved initial data, we analyze GW emission from equal- and unequal-mass BS-BH binaries and compare with matched BS-BS and BH-BH baselines. For equal masses, the BS-BH radiated energy increases with BS compactness and approaches the BH-BH limit for highly compact stars. For unequal masses, the $q = 2$ BS-BH configuration in our sample radiates slightly more GW energy than its matched BH-BH counterpart.

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Zhuan Ning. 2026-04-16. Boson star-black hole binaries: initial data and head-on collisions. https://doi.org/10.1103/9m6m-bvc6

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