Energy Extraction from Spinning Stringy Black Holes
Abstract
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 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.
Cite
@article{arxiv.2310.20040,
title = {Energy Extraction from Spinning Stringy Black Holes},
author = {Koushik Chatterjee and Prashant Kocherlakota and Ziri Younsi and Ramesh Narayan},
journal= {arXiv preprint arXiv:2310.20040},
year = {2023}
}
Comments
To be submitted to journal. Comments are welcome