The Effects of Gas Angular Momentum on Forming Magnetically Arrested Disks and Launching Powerful Jets

The Effects of Gas Angular Momentum on Forming Magnetically Arrested Disks and Launching Powerful Jets by Tom M. Kwan et al. on Wednesday 23 November In this Letter, we investigate jet-launching abilities of Bondi-like accretion flows with zero or low specific angular momentum by performing 3D general relativistic magnetohydrodynamic simulations. In order to check if relativistic jets can be launched magnetically, we thread the accretion flow with large-scale poloidal magnetic field, and choose a rapidly spinning black hole. We demonstrate that the magnitude of the initial gas specific angular momentum primarily controls whether the disk can reach and sustain the magnetically arrested disk (MAD) state that launches very powerful jets, at $\gtrsim 100\%$ energy efficiency. We find that MAD forms in the presence of even a very small amount of specific angular momentum, and episodic jets with an average energy efficiency of $\sim 10\%$ can still form even when the gas has zero initial angular momentum. Our results give plausible explanations to why jets can be produced from various astrophysical systems that lack large gas specific angular momenta, such as Sgr A*, wind-fed X-ray binaries, tidal disruption events, and long-duration gamma-ray bursts. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12726v1