The Blandford-Znajek process is a mechanism by which energy is extracted from a rotating black hole through electromagnetic fields, powered by the black hole's spin. This process is a key theoretical foundation for understanding how relativistic jets are launched from the vicinity of black holes, particularly in active galactic nuclei and quasars.

Blandford-Znajek Process

Energy extraction from black holes

Rotating black holes, also known as Kerr black holes, are a type of black hole that possess angular momentum, causing the surrounding spacetime to be dragged around with it in a phenomenon known as frame-dragging. This rotation gives rise to an ergosphere, a region outside the event horizon where objects cannot remain in place, and affects the black hole's accretion disk and jet formation.

Rotating Black Holes

Electromagnetic fields are physical fields produced by electrically charged objects, which affect the behavior of charged objects in the vicinity of the field. They encompass a wide range of phenomena, including electric fields, magnetic fields, and electromagnetic radiation, and are fundamental to the understanding of classical and modern physics.

Electromagnetic Fields

Black hole's spin

Theoretical foundation

Relativistic jets are highly collimated streams of plasma that are ejected at near-light speeds from the regions surrounding supermassive black holes, neutron stars, or active galactic nuclei. These jets play a crucial role in transporting energy and matter across vast cosmic distances, influencing galaxy formation and the intergalactic medium.

Relativistic Jets

Active Galactic Nuclei (AGN) are the extremely energetic centers of some galaxies, powered by accretion of matter onto supermassive black holes. They are among the most luminous and distant objects in the universe, providing insights into galaxy evolution and the behavior of matter under extreme gravitational forces.

Active Galactic Nuclei

Quasars are extremely luminous active galactic nuclei powered by supermassive black holes at the center of distant galaxies, emitting intense radiation across the electromagnetic spectrum. They serve as crucial probes for understanding the early universe and the evolution of galaxies over cosmic time.

Concepts

Your Lessons