New image reveals magnetic fields at black hole’s edge
A new image of the supermassive M87 black hole has been unveiled by the Event Horizon Telescope (EHT) collaboration involving UCL researchers, giving a closer look at how the black hole interacts with the matter surrounding it. The EHT team released the first image of a black hole in 2019, revealing a bright ring-like structure with a dark central region described as the black hole’s shadow.
The new observations, described in two papers in The Astrophysical Journal Letters, provide insights into the region just outside the black hole, where some matter is falling in, while another matter is being blown into space in the form of bright, powerful jets that extend at least 5,000 light-years away, beyond the galaxy in which the black hole resides.
Using the same data as for their first image, the collaboration analysed polarised light around the black hole – that is, light whose waves are vibrating in one direction only. The light becomes polarised when it is emitted in hot regions of space that are magnetised. By looking at how it has become polarised, astronomers can learn about the material that produced it.
Researchers say their new evidence brings us a step closer to understanding how these mysterious jets are produced, and how magnetic fields appear to act to keep hot gas out of the black hole, helping it resist gravity’s pull.
The EHT is an international collaboration set up to image a black hole by linking eight ground-based radio telescopes globally to make an Earth-sized virtual telescope with unprecedented sensitivity and resolution – a resolution sharp enough to measure an orange on the Moon from Earth.
The black hole that the collaboration has imaged is located in a galaxy called Messier 87, or M87, and is 55 million light-years away. It has a mass 6.5 billion times that of the Sun. The telescopes are located in volcanoes in Hawai’i and Mexico, mountains in Arizona and in the Spanish Sierra Nevada, the Chilean Atacama Desert, and Antarctica.