Magnetic fields around the black hole M87* have flipped

The Event Horizon Telescope , the global network of radio telescopes responsible for the first historic photograph of a black hole , M87* , has observed an unexpected phenomenon around that same object that puts theoretical models to the test: the magnetic fields surrounding it have reversed , so while in 2017 they were wrapping in one direction, in the 2021 images they appear to be wrapping in the opposite direction .

This is highlighted in a study published in the journal Astronomy & Astrophysics and led by the Massachusetts Institute of Technology, with the participation of the National Institute for Astrophysics of Cagliari and Bologna, the National Institute for Nuclear Physics of Naples and Cagliari, and the Federico II Universities of Naples, Cagliari, and Trieste. The data obtained shed light on a constantly evolving, turbulent environment in which magnetic fields play a crucial role in regulating how matter falls into the black hole and how energy is expelled .

"These results show how the EHT is evolving into a fully-fledged scientific observatory, capable not only of producing unprecedented images but also of building a progressive and coherent understanding of the physics of black holes," says Mariafelicia De Laurentis, EHT project scientist, researcher at the INFN and professor at Federico II University, co-author of the research led by Kazunori Akiyama: "It is a concrete demonstration of the enormous scientific potential of this instrument."

The first image of M87*, located about 55 million light-years from Earth and with a mass over six billion times that of the Sun, dates back to 2019. Now, thanks to observations made in 2017, 2018, and 2021, the collaboration has taken another step toward understanding how magnetic fields near the black hole change over time. "To reach these new milestones, it was also necessary to develop new analysis tools ," emphasizes Rocco Lico, INAF researcher and information technology officer at EHT, one of the study's authors, "and this makes the work even more exciting."