Dans le cadre du Prix international Georges Lemaître qui sera décerné cette année au Prof. Sheperd Doeleman, une conférence grand public sera organisée le 28 mars à l'auditoire A.02 (Auditoire des Sciences à Louvain-la-Neuve).
Title: “How to take a photo of a black hole”
Abstract :
Black holes are cosmic objects so small and dense, that nothing, not even light can escape their gravitational pull. Until recently, no one had ever seen what a black hole actually looked like. Einstein's theories predict that a distant observer should see a ring of light encircling the black hole, which forms when radiation emitted by infalling hot gas is lensed by the extreme gravity near the event horizon. The Event Horizon Telescope (EHT) is a global array of radio dishes, linked together by a network of atomic clocks to form an Earth-sized virtual telescope that can resolve the nearest supermassive black holes where this ring feature may be measured. On April 10th, 2019, the EHT project reported success: we have imaged a black hole, and have seen the predicted strong gravitational lensing that confirms the theory of General Relativity at the boundary of a black hole. This talk will cover how this was accomplished, the impact, and what the future holds for the study of black holes.
Un séminaire plus pointu est organisé le 27 mars.
Title: “Imaging supermassive black holes on horizon scales.”
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 nextgeneration EHT (ngEHT), an enhancement of the global array that will enable timelapse 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.
Plus largement, ces évènements sont associés à la journée mondiale du Big Bang mettra à l’honneur le grand scientifique Georges Lemaître, qui fut professeur à l’UCLouvain. Exceptionnellement, l’UCLouvain ouvrira la maison Georges Lemaître. Rendez-vous les 25 mars et 28 mars à Charleroi pour mieux connaître le « Einstein belge ».