Spinning black hole power jet by magnetic flux

Black holes are at the center of almost every galaxy studied to date. They have an unimaginably large mass and therefore attract matter, gas and even light. But they can also emit dust in the form of plasma jets – a kind of plasma stream that is emitted with enormous energy from the center of the galaxy. A plasma jet can extend several hundred thousand light-years far into space.

When this intense radiation is emitted, the black hole remains hidden because the light rays are bent nearby, leading to the appearance of a shadow. This was recently reported by researchers from the Event Horizon Telescope (EHT) for the massive black hole in the giant elliptical galaxy M87.

In quasar 3C279 – also a black hole – the EHT team discovered another phenomenon: At a distance of more than a thousand times, the shadow of the black hole, the core of a plasma jet, suddenly shook. How the energy for this jet could get there if through an invisible chimney was not yet known.

Extremely flickering gamma radiation detected

This quasar has now been observed with the NASA space telescope Fermi-LAT by astrophysicist Amit Shukla, who conducted research until 2018 at Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany. He now works at the Indian Institute of Technology in Indore. Shukla discovered that the core of the jet, which was found in the millimeter wavelength range, also emits high-energy gamma radiation, but with an extremely flickering brightness. This brightness can double within a few minutes, as reported in the magazine Nature communication.

The special pattern of the sequence of changes in brightness is characteristic of a universal process called magnetic connection, which occurs in many astrophysical objects with strong magnetic fields. So much activity also has to do with the dynamics of magnetic fields and reconnection. This was recently demonstrated by observing ‘campfire’ in the sunbeam with the Solar Orbiter mission of the European Space Agency ESA.

Invisible stored energy is suddenly released

But back to the quasar 3C279: “I saw how the analysis of the data revealed the special pattern of magnetic connection in the light curve. It felt like I had suddenly deciphered a hieroglyph in the black hole alphabet,” says Amit Shukla.

Upon reconnection, energy that is initially invisibly stored in the magnetic field is suddenly released into several “mini-jets.” In these jets, particles are accelerated, which then produce the observed gamma radiation. Magnetic reconnection would explain how the energy reaches the core of the jet out of the black hole and where it eventually comes from.

Energy from the rotating black hole

Professor Karl Mannheim, head of the JMU chair for astronomy and co-author of the publication, explains “Space at the black hole in quasar 3C279 is forced to curl into corrosion. Magnetic fields anchored to the plasma around it black hole displaces the jet slows the rotation of the black hole and converts some of its rotational energy into radiation. ”