
Outflowing winds of gas and dust from the accretion disk surrounding a black hole.Accretion disk winds are powerful outflows of gas and dust launched from the swirling disk of matter that forms around a black hole as it pulls in material from its surroundings. These winds are not a minor side effect; they are a major channel through which the black hole's gravitational energy is returned to the galaxy, often carrying away more mass than is actually consumed by the black hole itself. This makes them a critical component in understanding how black holes 'regulate' their own growth and influence the evolution of their host galaxies.
The theoretical concept of disk winds was developed in the 1970s and 1980s, with early work by researchers like Mitchell Begelman and Roger Blandford, who recognized the importance of magnetic fields in launching such outflows.
The disk is heated to extreme temperatures by friction and gravitational compression, causing it to radiate intensely. This radiation pressure, along with magnetic fields that thread the disk, can accelerate gas outward, overcoming the black hole's gravity. The result is a high-speed, often collimated outflow that can extend for thousands of light-years, carving out bubbles and cavities in the surrounding interstellar medium.
Observations of disk winds, particularly in X-ray and ultraviolet spectra, are used to measure black hole accretion rates and to study feedback mechanisms that shape galaxy evolution.
The wind from the supermassive black hole at the center of our Milky Way, Sagittarius A*, is so powerful that it is actively stripping gas from nearby molecular clouds, suppressing star formation in the galactic center.
| r_A | variable | Alfvén radius — radius metre |
| μ | variable | Magnetic dipole moment of the star — magnetic dipole moment ampere square metre |
| G | variable | Gravitational constant — gravitational constant cubic metre per kilogram per second squared |
| M | variable | Mass of the accreting star — mass kilogram |
| Ṁ | variable | Mass accretion rate — mass accretion rate kilogram per second |



















