phenomenon

jet magnetic signature

The distinctive magnetic field pattern revealed by twisted or structured jets from cosmic accelerators.
20 related articles

Description

Jet magnetic signature refers to the distinctive pattern of magnetic fields revealed by the twisted or structured appearance of relativistic jets emitted from cosmic accelerators such as active galactic nuclei, microquasars, and gamma-ray bursts. These jets are collimated outflows of plasma moving at speeds close to the speed of light, and their magnetic fields play a crucial role in their formation, collimation, and acceleration. The magnetic signature can be observed through the polarization of light emitted by the jet, which reveals the orientation and structure of the magnetic field along the jet's path.

History

The study of jet magnetic fields began with early radio observations of active galaxies in the 1970s, which revealed polarized emission from jets. The concept of helical magnetic fields in jets was developed in the 1980s and has been supported by increasingly detailed observations across the electromagnetic spectrum.

How it works

The magnetic fields in jets are thought to be generated by the accretion disk around a compact object, such as a black hole, and are twisted into helical structures as the disk rotates. This helical magnetic field helps to collimate the jet, focusing the plasma into a narrow beam, and can also accelerate particles to high energies through magnetic reconnection and shock acceleration. The observed polarization patterns in jet emission, such as the degree and angle of polarization, provide a direct probe of the magnetic field geometry, allowing astronomers to map the field's structure and its evolution along the jet.

In practice

Analyzing jet magnetic signatures helps astronomers understand the physics of black hole accretion and jet launching, and it is used to interpret observations from radio telescopes like the Very Large Array and the Event Horizon Telescope.

Fun fact

The magnetic field in some jets can be so strong that it would be millions of times stronger than the Earth's magnetic field, yet it is still not enough to prevent the jet from bending over thousands of light-years.

Concept graph →

Related articles · 20

A Quieting Fountain: Evolution of Protoplanetary Disk Winds as Seen by JWST
Seventy-two protoplanetary disks, swirling cocoons of cosmic dust and gas, came under the gaze of the MIRI instrument on JWST. Most of them shoot outflows into space: dense conical structures and narrow, high-speed jets. They blast like fountains. This process is not accidental.
The Spotlight That Turned Away: The Mystery of Transient AT 2019ijn
The cosmos is full of screams we can't hear. Every time a black hole tears a star apart, a blinding flash is born, and often — a narrow relativistic jet, shooting out thousands of light-years. But if that searchlight is aimed away from Earth, we see only a faint afterglow — a radio echo arriving with a delay.
Galaxies2026-07-023 minarXiv:2607.02665
Corkscrew Galaxy: How a Twisted Jet Reveals the Magnetic Signature of Clusters
At the center of many galaxies lurks a supermassive black hole, ejecting relativistic plasma jets over hundreds of kiloparsecs. One such is the radio galaxy ESO 137-G007 in the Norma Cluster, known as the “Corkscrew Galaxy” for its twisted jets.
High Energy2026-06-082 minarXiv:2606.08931express
Cosmic Jet Slams into a Cloud
A fire hose blasts into a snowdrift. The water doesn't just shove the snow aside — at the point of impact, spray, steam, and a roar are born. That's roughly how jets behave: narrow streams of matter shooting out from around a black hole at enormous speeds.
Materials2026-05-232 minarXiv:2605.24320express
Magnetic Dualism in a Crystal
A translator works in two worlds at once: to an outside observer, they are silent and unobtrusive, but inside their mind, a flurry of activity unfolds along clear lines of meaning. Altermagnets, a recently discovered class of magnetic materials, are much the same.
High Energy2026-05-131 minarXiv:2605.12931express
The Bicycle Dynamo in Space: How Collapsar Jets Are Born
A massive star collapses, and a black hole is born, surrounded by a disk of incandescent plasma. For narrow jets to burst out of this disk, an ordered magnetic field is needed. But inside the star, it's tangled.
High Energy2026-05-131 minarXiv:2605.13719express
Cosmic Top: How a Wobbling Jet Explained the GW170817 Mystery
In 2017, detectors picked up a tremor in space — gravitational waves from the merger of two neutron stars. At the same moment, telescopes saw a flash. For the first time, one event spoke in two languages at once: light and gravity.
Cosmic Instrument: Resonant Songs of Rotating Wormholes
Einstein and Rosen imagined a bridge connecting two sheets of reality. Wheeler gave it a name — wormhole, and Thorne with Morris proved: the tunnel is traversable if you fill it with exotic matter.
Plasma Physics2026-04-052 minarXiv:2604.04276express
What a Cosmic Hurricane Sounds Like
When water boils in a kettle, waves of steam ripple through the kitchen. A similar process happens in space, in plasma — gas so hot that electrons are stripped from atoms. Around black holes and neutron stars, this plasma isn't just hot: its particles zip around at nearly the speed of light.
High Energy2026-03-262 minarXiv:2603.25846express
Star Explosion: How Magnetic Fields and Rotation Forge Cosmic Jets
A massive star, 40 times heavier than the Sun, dies in a fraction of a second. Its core compresses like a spring squeezed too hard, then snaps back: that's a supernova explosion. But what if the star is also spinning, like a figure skater pulling in their arms, and threaded with a magnetic field, like invisible strings?
High Energy2026-03-171 minarXiv:2603.16647express
Cosmic Accelerators: How Jets Boost Particles
A stream of water from a hose hitting a wall splashes sideways. Astrophysical jets behave similarly — narrow plasma flows ejected from the vicinity of black holes or young stars. When such a flow encounters resistance from surrounding gas, a shock wave forms inside it, akin to a standing wave in a fast-flowing river.
Nuclear Experiment2026-03-151 minarXiv:2603.14385express
Jets in a Leaden Haze
When two lead nuclei collide at tremendous speed, a cloud of scorching matter is born for an instant — denser and hotter than the center of the Sun. Through this cloud fly jets of particles: narrow, laser-like beams knocked out by the impact. The CMS detector captures their tracks and shows how the jets change as they fight through the hot 'fog'.
High Energy2026-03-062 minarXiv:2603.06294express
Trembling Jets of Black Holes
A garden hose blasts a powerful stream of water. If you pinch it or give it a jerk, the stream starts to writhe like a snake, and spray flies everywhere. Something similar happens with the giant plasma jets that black holes shoot out.
Galaxies2026-02-252 minarXiv:2602.21821express
Jellyfish Galaxies: Supersonic Winds Ignite Star Formation
A galaxy plunges into a dense cluster like a runner into a crowd. The oncoming gas, known as the intracluster medium, strips away its own gas, stretching it into a long, glowing tail. Astronomers call these galaxies jellyfish: they have a body and flowing tentacles of stripped material. But only in a few do new stars ignite within those tentacles.
Nuclear Experiment2026-02-201 minarXiv:2602.18279express
How a Hot Cloud Bends a Jet
When two protons collide at enormous speed, a narrow beam of particles (a jet, like the spray from a stone thrown into water) shoots out from the point of impact. In collisions of heavy lead nuclei, things are more complicated: a hot cloud forms inside, which interferes with the jet's straight flight.
Galaxies2026-02-101 minarXiv:2602.09404express
One-Sided Fountain from a Young Star
A young star that hasn't yet ignited its thermonuclear furnace is surrounded by a rotating disk of gas and dust. To gain mass, it needs to shed excess rotation — otherwise, material won't fall onto the star but will keep orbiting. Usually, this excess is carried away by two narrow gas jets that shoot from the star's poles in opposite directions, like two fountains.
High Energy2026-02-051 minarXiv:2602.05601express
Blazar Flares: How to Tell Particle Accelerators Apart
A blazar is a distant galaxy with a plasma jet shooting from its center, aimed almost directly at us. Inside this jet, particles are accelerated to near-light speeds and emit powerful radiation.
Stellar2026-02-021 minarXiv:2602.01742express
The Solar Knot That Unties Itself
The Sun frequently launches narrow plasma jets, coronal jets, that resemble fountains of superheated gas erupting from the star's atmosphere. One such eruption, which occurred on November 10, 2022, caught scientists' attention: it was accompanied by a C1.1-class flare and had an unusually wide cone.
High Energy2026-01-011 minarXiv:2601.00441express
Plasma Sphere Explains Magnetars and Radio Bursts
A magnetar is a neutron star with a magnetic field a quadrillion times stronger than Earth's. Sometimes it ejects a blob of plasma, like a tiny balloon with thousands of invisible springs bouncing around inside.