It has recently come to light that astronomers have revealed the presence of magnetic fields around a black hole for the first time ever. This image of a black hole at the centre of the Messier 87 (M87) galaxy shows a bright ring-like structure with a dark central region i.e. the black hole’s shadow. The image has been produced by the Event Horizon Telescope (EHT) collaboration.
As reported by Event Horizon Telescope, astronomers have discovered that a significant fraction of the light around the M87 black hole is polarised. “This work is a major milestone: the polarisation of light carries information that allows us to better understand the physics behind the image we saw in April 2019, which was not possible before,” explains Iván Martí-Vidal, also Coordinator of the EHT Polarimetry Working Group and GenT Distinguished Researcher at the Universitat de València, Spain. He adds that “unveiling this new polarised-light image required years of work due to the complex techniques involved in obtaining and analysing the data”.
The report further states that this new EHT image of the black hole and its shadow in polarised light has allowed astronomers to look into the region just outside the black hole for the first time. This is also the region where the “interplay between matter flowing in and being ejected out is happening”. All these observations are providing new insights into the structure of the magnetic fields that exist just outside the black hole.
“The observations suggest that the magnetic fields at the black hole’s edge are strong enough to push back on the hot gas and help it resist gravity’s pull. Only the gas that slips through the field can spiral inwards to the event horizon,” explains Jason Dexter, Assistant Professor at the University of Colorado Boulder, USA, and coordinator of the EHT Theory Working Group.
Image source: EHT