The Dance of Gears: Why Some Black Holes Blow Winds and Others Shoot Jets ✛

Original: "Winds Versus Jets in Active Galactic Nuclei"

· David Garofalo, Chandra B. Singh, Atticus Magerko, Marco Botello, Sophia Soto, Max North

arXiv:2607.22418v1 · 2026-07-24 · CC BY 4.0 · 2 min

Astronomers have found that the fate of infalling gas — whether it becomes an ultrafast wind or a relativistic jet — depends not only on the black hole's mass and spin but also on the direction of rotation of the accretion disk relative to it.

The fastest wind in the Universe travels at 0,58 times the speed of light. It covers the distance from Earth to the Moon in two seconds. This wind is not a jet stream but a broad flow of gas erupting from the center of a galaxy. Not all black holes work the same: some create such hurricanes, while others produce narrow plasma beams. The answer resembles the meshing of gears.

Astronomers collected data on 62 active nuclei: radio-loud quasars, radio-quiet quasars, and Seyfert galaxies. Using high-resolution spectroscopy, they measured gas outflow velocities and black hole masses. The result surprised them. Contrary to expectations, no correlation between mass and speed was found. Instead, another pattern emerged: the fastest winds — up to 0,58 c — blow exclusively in radio-quiet systems lacking jets. In radio-loud systems, winds are more moderate, and sometimes both coexist.

The record holder — quasar SDSS J1029+2623 — ejects gas at 174 000 km/s. That's 58% of the speed of light.

Everything depends on the direction of rotation. Two gears. One is the black hole itself, spinning like a top, described by Roy Kerr. The second is the Accretion disk of gas. If they rotate in the same direction, the disk comes very close to the horizon — to a distance of just 1,24 gravitational radii. Gravitational energy is released with an efficiency of up to 30% (nearly a third of the mass!) and drives a powerful radiation wind. The jet is suppressed under these conditions. If the disk rotates counter to the hole, no meshing occurs. The disk stops far away — about 9 gravitational radii. Efficiency drops to 5–6%, winds weaken, and enough magnetic flux remains to launch a narrow beam.

This model also explains the oddities of elliptical galaxies — products of mergers. There, quasars with simultaneous winds and jets are sometimes observed. Probably, these are galaxies that experienced a short episode of counter-rotation. The magnetic field had time to twist into a jet, but then the disk reversed, and the wind became dominant.

That ultrafast wind, which reaches the Moon in two seconds, is born from a perfect alignment of directions. The black hole and its disk rotate like two interlocking gears — and spit out gas as if a giant fan were torn from its axle.

Whole graph →

The fastest known wind — from quasar SDSS J1029+2623—travels at 0,58c, covering the distance from Earth to the Moon in two seconds.

r_{\text{ISCO}} = r_g \left[3 + Z_2 \mp \sqrt{(3-Z_1)(3+Z_1+2Z_2)}\right], \quad Z_1 = 1 + (1-a^2)^{1/3}[(1+a)^{1/3}+(1-a)^{1/3}], \quad Z_2 = \sqrt{3a^2+Z_1^2}

Defines the closest orbit to a black hole where a disk can rotate stably. The minus sign is taken when the disk rotates in the same direction as the black hole; the plus sign when it rotates in the opposite direction.

Scientists

Stephen Hawking Jacob Bekenstein John Archibald Wheeler Roger Penrose Margaret Burbidge Maarten Schmidt

Concepts

accretion disk wind black hole wind relativistic jets microquasar galactic winds blazar changing agn activity radio loud quasar seyfert galaxy active galaxy black hole recoil jet protoplanetary disk winds mass ratio quasar obscured agn x ray binary active galactic nucleus red dots spin rate torus

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The Dance of Gears: Why Some Black Holes Blow Winds and Others Shoot Jets ✛