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The astrophysical signatures of powerful jets at different scales — stellar compact objects and supermassive black holes — call attention to astronomers and astrophysicists due to the wide range of output energy, producing electromagnetic emissions from radio band to near-infrared, X-rays, and high-energy gamma-rays. Recent multi-wavelength and multi-scale observations of the M87 jet show a high precision the morphology of the jet launching region.

Understanding the mechanism of jet launching is an exciting topic in modern astrophysics. A widely accepted model proposes that magnetic fields could extract rotational energy from the black hole. Where the poloidal magnetic field becomes twisted due to frame-dragging effects of the spinning black hole, and a toroidal magnetic field develops. Such configuration generates magnetic pressure providing the power to launch the jet. The model is called Blandford–Znajek mechanism.

(a) Example of three-dimensional GRMHD simulation using JETSET tools. Yellow lines show magnetic field lines in the collimated jet where the plasma is highly magnetized, in this example the jet was launched naturally starting from weak magnetic filed in the accretion disk. The red region is the accretion disk. [Image: Alejandro Cruz-Osorio]. (b) Ratio between toroidal and poloidal magnetic field components, time, and azimuth-angle-averaged from GRMHD simulation. We can identify where the toroidal component dominates over the poloidal one, white-blue region, where the jet is launching. [Images: Alejandro Cruz-Osorio]. (c) Cartoon of magnetic field evolution to generate enough toroidal magnetic pressure to launch the jet. [Image: Alexander Tchekhovskoy, Northwestern University]