2023/10/30 by Koushik Chatterjee, Prashant Kocherlakota, Chatterjee, Koushik +5 · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics of Galaxies (astro-ph.GA) #Black Holes and Theoretical Physics #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Astrophysical Phenomena (astro-ph.HE) #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.2310.20040
openalex publication_date 2023/10/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We perform the first numerical simulations modeling the inflow and outflow of magnetized plasma in the Kerr-Sen spacetime, which describes classical spinning black holes (BHs) in string theory. We find that the Blandford-Znajek (BZ) mechanism, which is believed to power astrophysical relativistic outflows or ``jets'', is valid even for BHs in an alternate theory of gravity, including near the extremal limit. The BZ mechanism releases outward Poynting-flux-dominated plasma as frame-dragging forces magnetic field lines to twist. However, for nonspinning BHs, where the frame-dragging is absent, we find an alternate powering mechanism through the release of gravitational potential energy during accretion. Outflows from non-spinning stringy BHs can be approximately 250% more powerful as compared to Schwarzschild BHs, due to their relatively smaller event horizon sizes and, thus, higher curvatures. Finally, by constructing the first synthetic images of near-extremal non-Kerr BHs from time-dependent simulations, we find that these can be ruled out by horizon-scale interferometric images of accreting supermassive BHs.