The Event Horizon Telescope (EHT) collaboration has published new results describing for the first time how light from the edge of the supermassive black hole M87* spirals as it escapes the black hole’s intense gravity. This signature, known as circular polarisation, is a consequence of the rotation of the electric field in the radio waves. As it travels, it carries information about the magnetic field and types of energetic particles around the black hole. The new work supports earlier findings from the EHT that the magnetic field around the M87* black hole is strong enough to occasionally prevent the black hole from swallowing nearby matter. Read the publication Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes in Astrophysical Journal Letters (F. Roelofs, M.D. Johnson, A. Chael, M. Janssen, M. Wielgus, and the EHT Collaboration, The Astrophysical Journal, 8 November 2023, DOI: 10.3847/2041-8213/acff6f). Read more in the EHT press release, the MPIfR press release, the ALMA press release and the JIV-ERIC press release.
Image: © George Wong, a computer simulation of a disk of plasma around the supermassive black hole at the center of the M87 galaxy. A new analysis of the circularly polarized, or spiraling light, in EHT observations shows that magnetic fields near the black hole are strong. These magnetic fields push back on infalling matter and help launch jets of matter at velocities near the speed of light out.