Scientists confirm presence of supermassive black hole at heart of the Milky Way

GRAVITY combines the light from four different telescopes of Very Large Telescope to create a virtually huge telescope

Scientists have finally confirmed the presence of a supermassive black hole at the heart of our galaxy.

The finding came after the researchers from various institutions - including the Max Planck Institute for Extraterrestrial Physics, Max Planck Institute for Astronomy, Observatories of Paris and Grenoble and the Universities of Cologne, Lisbon and Portugal - used the European Southern Observatory's (ESO) highly sensitive GRAVITY instrument to watch infrared radiation flares originating from the accretion disc around the alleged black hole, named Sagittarius A*.

GRAVITY is an interferometer installed on ESO's Very Large Telescope (VLT). This near-infrared astrometric and imaging instrument can spot even small features of faint objects, like the centres of galaxies located very far away.

The instrument combines the light from four telescopes of VLT to create a virtually huge telescope, about 130m in diameter. Its astrometric capacity enables astronomers to accurately measure distances in space, thus detecting movements of distant objects in small periods of time.

The evidence of a supermassive object present in the centre of our galaxy comes in the form of gas clouds that appear to circle the galactic centre. The accretion disc, or the belt of gas, is about 10 light-minutes in diameter, according to scientists.

Scientists also found that these clumps of gases complete a circular path of 150 million miles at a speed of about 30 per cent of the speed of light.

Earlier this year, in May, astronomers had observed strong infrared emissions when a star named S2 passed through the intense gravitational field close to Sagittarius A*. These infrared emissions originated from magnetic interactions happening in the hot gases orbiting close to the black hole. The observations were made using GRAVITY as well as SINFONI integral field instrument on the VLT.

The detailed findings of the study were published in the journal Astronomy & Astrophysics on 31 October 2018.