Global resistive MHD accretion flows around spinning AGNs: the effect of resistivity on the MAD state.

Mohammed Ramiz Aktar^1*, Kuo-Chuan Pan^1,2,3, Toru Okuda⁴

¹Department of Physics and Institute of Astronomy, National Tsing Hua University, Hsinchu City, Taiwan
²Center for Theory and Computation, National Tsing Hua University, Hsinchu City, Taiwan
³Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei, Taiwan
⁴Hakodate Campus, Hokkaido University of Education, Hakodate, Japan

* Presenter:Mohammed Ramiz Aktar, email:ramizaktar@gmail.com

We conduct 2D and 3D resistive magnetohydrodynamic (Res-MHD) simulations to study accretion flows around spinning Active Galactic Nuclei (AGNs). To replicate the space-time geometry of black holes, we utilize an effective Kerr potential. To explore the effects of magnetic resistivity on accretion and ejection around black holes, we vary the resistivity values as follows: $\eta = 10^{-2}, 5 \times 10^{-3}, 10^{-5}$, and $\sim 0.0$. Our simulations indicate that a 'magnetically arrested disk (MAD)' state is achieved in all resistive cases in 2D and 3D models. However, the level of Magnetorotational Instability (MRI) turbulence is significantly lower in the high-resistivity model compared to the low-resistivity flow. Notably, we observe indications of plasmoid formation in the moderately low-resistive flow ($\eta = 10^{-3}$). We discuss the potential implications of these plasmoids concerning radio flaring events of SgrA*.

Keywords: accretion, accretion disks, black hole physics, magnetohydrodynamics (MHD), jets and outflows