For the first time, magnetic fields in the immediate vicinity of the black hole could be detected and made visible, as announced by the Max Planck Institute for Radio Astronomy in Bonn on Wednesday, March 24th. «That is very important to us. This enables us to better understand how the luminous structures are created in the vicinity of a black hole, ”explained Anton Zensus, director at the institute.
The data once again come from the “Event Horizon Telescope” (EHT), for which scientists have interconnected various radio telescopes around the world. In 2019, the EHT provided the first image of a black hole – a scientific sensation. Since then, the analysis of the data has continued. Now the EHT observations show the first image of the magnetic field distribution in the bright ring around the so-called shadow of the black hole in the center of M87.
Why do black holes “spit”?
The key to this was provided by the observation that the radio radiation is polarized, i.e. has a non-random direction of oscillation. Polarized radiation is considered by astrophysicists to be a reliable indicator of the presence of magnetic fields.
Magnetic fields, in turn, play a crucial role in the formation of so-called jets. The background to this is that black holes absorb large amounts of matter. However, some of this matter does not fall into the black hole, but is shot out into space as super-hot plasma. “If we map the immediate vicinity of the black hole and understand the magnetic fields, we can ultimately begin to understand how these jets are formed,” explained Anton Zensus. “We are measuring something that will be important for the interpretation of the jets.”
In black holes, the mass of a few to several billion suns is compressed into an extremely small region. Due to the immense gravity, not even light can escape from the direct environment, hence the name. Black holes can arise, for example, when burnt-out giant stars collapse under their own weight. The exact origin of supermassive holes like in M87 has not yet been clarified.