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arXiv · 2301.06564

Bondi-Hoyle-Lyttleton accretion onto a rotating black hole with ultralight scalar hair

Alejandro Cruz-Osorio·Luciano Rezzolla·Fabio Duvan Lora-Clavijo·José Antonio Font·Carlos Herdeiro·Eugen Radu
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Abstract

We present a numerical study of relativistic Bondi-Hoyle-Lyttleton (BHL) accretion onto an asymptotically flat black hole with synchronized hair. The hair is sourced by an ultralight, complex scalar field, minimally coupled to Einstein's gravity. Our simulations consider a supersonic flow parametrized by the asymptotic values of the fluid quantities and a sample of hairy black holes with different masses, angular momenta, and amount of scalar hair. For all models, steady-state BHL accretion solutions are attained that are characterized by the presence of a shock-cone and a stagnation point downstream. For the models of the sample with the largest component of scalar field, the shock-cone envelops fully the black hole, transitioning into a bow-shock, and the stagnation points move further away downstream. Analytical expressions for the mass accretion rates are obtained after fitting the numerical results, which can be used to analyze black-hole formation scenarios in the presence of ultralight scalar fields. The formation of a shock-cone leads to regions where sound waves can be trapped and resonant oscillations excited. We measure the frequencies of such quasi-periodic oscillations and point out a possible association with quasi-periodic oscillations in the X-ray light curve of Sgr~A* and microquasars.

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Alejandro Cruz-Osorio, Luciano Rezzolla, Fabio Duvan Lora-Clavijo, José Antonio Font, Carlos Herdeiro, Eugen Radu. 2023-06-16. Bondi-Hoyle-Lyttleton accretion onto a rotating black hole with ultralight scalar hair. https://doi.org/10.1088/1475-7516%2F2023%2F08%2F057

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