Prix Georges Lemaître 2023, scientific talk
Abstract:
The Event Horizon Telescope (EHT) has imaged the 6.5 billion solar mass black hole at the center of the bright radio galaxy Virgo A (M87) with Schwarzschild radius scale resolution. This was accomplished using the technique of Very Long Baseline Interferometry (VLBI) coupled with advances that allowed observations at 1.3mm wavelength. Subsequent analysis of the M87 data has revealed ordered magnetic field structures on horizon scales with implications for accretion and jet launching mechanisms. Most recently, the EHT has imaged SgrA*, the 4 million solar mass black hole at the center of the Milky Way, enabling tests of General Relativity on an object with a mass known to better than 1%. Future work is now focused on the next- generation EHT (ngEHT), an enhancement of the global array that will enable time- lapse dynamical reconstructions of the M87 jet and near real-time movies of SgrA*. This talk will cover the background and instrumental foundation of the EHT project, the process of imaging and implications of results to date, and progress towards completing the ngEHT by the end of this decade.