It has long been known that super-powerful black holes are surrounded by clouds of plasma, the temperature of which can reach a billion degrees Celsius. Experts have also long suspected that this plasma is heated by a magnetic field around a black hole. However, these fields have never been measured so far, so there is still uncertainty.
Japanese scientists looked at two active black holes. IC 4329A, which is located at a distance of 200 million light years and NGC 958, 580 million light years away from us. The measurements were taken with an ALMA telescope and then confirmed with VLA from the USA and ATCA from Australia.
The measurements show that the crowns of both black holes have a diameter of 40 Schwarzschild radii. In the case of black holes it is a surface limited by the horizon of events. The magnetic field strength is calculated at 10 gaus.
Although we confirmed the existence of synchrotron radiation from both objects, it turns out that the measured magnetic field is too weak to heat the crowns around the black holes, says the main author of the study Yoshiyuki Inoue. As the same conclusions were drawn from the study of both black holes, it can be assumed that this is a universal phenomenon.