2021/02/28 by Federico Cattorini, Bruno Giacomazzo, Francesco Haardt +1
Physics and Astronomy · #Accretion (finance) #Angular momentum #Angular momentum coupling #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Binary black hole #Black hole (networking) #Classical mechanics #Gravitational wave #Magnetic field #Magnetization #Magnetohydrodynamics #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Rotating black hole #Specific relative angular momentum #Spin-flip #Total angular momentum quantum number #astro-ph.HE #gr-qc
paper · pdf · doi:10.1103/physrevd.103.103022
published as Phys. Rev. D 103, 103022 (2021) · 15 pages, 12 figures
openalex created_date 2021/03/15 · openalex publication_date 2021/05/28 · arxiv created 2021/06/03 · arxiv updated 2021/06/04 · openalex updated_date 2026/08/05
We perform the first suite of fully general relativistic magnetohydrodynamic simulations of spinning massive black hole binary mergers. We consider binary black holes with spins of different magnitudes aligned to the orbital angular momentum, which are immersed in a hot, magnetized gas cloud. We investigate the effect of the spin and degree of magnetization (defined through the fluid parameter \ensuremathβ^\ensuremath-1\ensuremath≡pmag/pfluid) on the properties of the accretion flow. We find that magnetized accretion flows are characterized by more turbulent dynamics, as the magnetic field lines are twisted and compressed during the late inspiral. Postmerger, the polar regions around the spin axis of the remnant Kerr black hole are magnetically dominated, and the magnetic field strength is increased by a factor approximately 102 (independently from the initial value of \ensuremathβ^\ensuremath-1). The magnetized gas in the equatorial plane acquires higher angular momentum and settles in a thin circular structure around the black hole. We find that mass accretion rates of magnetized configurations are generally smaller than in the unmagnetized cases by up to a factor approximately 3. Black hole spins have also a suppressing effect on the accretion rate, as large as approximately 48%. As a potential driver for electromagnetic emission, we follow the evolution of the Poynting luminosity, which increases after merger up to a factor approximately 2 with increasing spin, regardless of the initial level of magnetization of the fluid. Our results stress the importance of taking into account both spins and magnetic fields when studying accretion processes onto merging massive black holes.