Astronomers recently made a significant discovery regarding powerful magnetic fields swirling around the black hole located at the centre of the Milky Way. According to the European Southern Observatory, a new image from the Event Horizon Telescope (EHT) revealed, for the first time in polarised light, a ring of magnetic fields surrounding the Sagittarius A* black hole. These magnetic fields are said to be similar to those observed around the M87* black hole at the core of the M87 Galaxy. This finding leads researchers to believe that strong magnetic fields may be common among all black holes.
Sara Issaoun, a member of Harvard’s Center for Astrophysics and co-lead of the project, explained that the new discovery shows the presence of strong, twisted, and organised magnetic fields near the black hole at the heart of the Milky Way galaxy. This was made possible through polarised light images, which enabled astronomers to isolate the magnetic field lines of the black hole.
Supermassive black holes, which are found at the centre of galaxies, are significantly larger in mass compared to the Sun, with masses ranging from millions to billions of times greater. Although these entities emerged early in the universe, their origins remain a mystery. What makes them difficult to study is that nothing, not even light, can escape their immense gravitational pull, making them impossible to observe directly. However, with the EHT capturing images of M87* in 2019 and Sagittarius A* in 2022, astronomers were able to view the halo of light that forms due to the inflow and outflow of matter and gas around black holes.
Angelo Ricarte, a member of the Harvard Black Hole Initiative and co-lead of the project, highlighted the significance of imaging polarised light emitted by hot gas surrounding black holes. This allowed researchers to directly understand the structure and strength of the magnetic fields that drive the flow of matter towards black holes. Mariafelicia De Laurentis, deputy scientist at the EHT and professor at the University of Naples Federico II in Italy, added that the presence of strong magnetic fields around both M87* and Sagittarius A* suggests a universal and possibly fundamental characteristic of these systems.