Albert Einstein's groundbreaking theory of General Relativity published in 1915 predicted that massive bodies deflected light, a prediction that was confirmed by Sir Arthur Eddington in 1919. An astonishing consequence of this property is that we can use galaxies in the distant Universe as magnifying glasses to study even more distant objects. I will report here on using a distant galaxy to study the X-ray emission from a quasar - a supermassive black hole at the center of a galaxy swallowing matter which shines brightly just before falling into the black hole. Interestingly, the X-rays observed with the Chandra X-ray telescope allow us to map out the curved spacetime close to the black hole, and to constrain the properties of the lensing galaxy, i.e. the ratio of the mass of dark matter and stars along the line of sight, and the typical masses of the stars.
Exploring the Spacetime Around Supermassive Black Holes with Gravitational Lenses
Professor Henric Krawczynski, Department of Physics, Washington University
April 1, 2017 at 10:00 am