Max Planck Institute for Extraterrestrial Physics | 2018 Nov 29
Detailed observations of the quasar 3C 273 with the GRAVITY instrument reveal the structure of rapidly moving gas around the central super-massive black hole, the first time that the so-called “broad line region” could be resolved. The international team of astronomers was thus able to measure the mass of the black hole with unprecedented precision. This measurement confirms the fundamental assumptions of the most commonly used method to measure the mass of central black holes in distant quasars. Studying these black holes and determining their masses is an essential ingredient to understanding galaxy evolution in general.
More than 50 years ago, the astronomer Maarten Schmidt identified the first “quasi-stellar object” or quasar, named 3C 273, as an extremely bright but distant object. The energy emitted by such a quasar is much greater than in a normal galaxy such as our Milky Way and cannot be produced by regular fusion processes in stars. Instead, astronomers assume that gravitational energy is converted into heat as material is being swallowed by an extremely massive black hole.
An international team of astronomers has now used the GRAVITY instrument to look deep into the heart of the quasar and was able to actually observe the structure of rapidly moving gas around the central black hole. So far, such observations had not been possible due to the small angular size of this inner region, which is about the size of our Solar system but at a distance of some 2.5 billion lightyears. The GRAVITY instrument combines all four ESO VLT telescopes in a technique called interferometry, which allows a huge gain in angular resolution, equivalent to a telescope with 130 metres in diameter. Thus the astronomers can reveal structures at the level of 10 micro-arcseconds, which corresponds to about 0.1 lightyears at the distance of the quasar (or an object the size of a 1-Euro-coin on the Moon). ...
Gas Clouds Whirling around Black Hole Form Heart
of Extremely Distant Luminous Astronomical Object
American Friends of Tel Aviv University (AFTAU) | 2018 Nov 29
Spatially Resolved Rotation of the Broad-Line Region of a Quasar at Sub-Parsec Scale ~ GRAVITY Collaboration