Astronomers have captured the moment the gravity of a supermassive black hole destroyed a star that drifted too close causing a fast-moving jet of cosmic material and energy to be ejected.
The moment the black hole destroyed a star took place in a pair of colliding galaxies called Arp 299, nearly 150 million light-years from Earth. According to the University of Manchester, at the centre of one of the galaxies, a black hole 20 million times bigger than the Sun destroyed a star more than twice the Sun’s mass, setting off a chain of events that revealed important details of the encounter.
Dr Rob Beswick, from the Jodrell Bank Centre for Astrophysics at the University of Manchester’s School of Physics and Astronomy, UK, said: “This is a fantastic discovery and an extremely important result in astronomy. It is a testament to the persistence of the science team and demonstrates the power of globally co-ordinated VLBI observations, including multiple telescopes from Jodrell Bank Observatory and the e-MERIN array in the UK.”
How were the observations carried out?
Scientists observed as the black hole destroyed a star using multiple radio-telescope antennas, separated by thousands of miles, to gain the resolving power required to detect the expansion of an object so distant.
The discovery has taken over a decade to unravel with the first indication in 2005. Astronomers using the William Herschel Telescope in the Canary Islands discovered a bright burst of infrared emission coming from the nucleus of one of the colliding galaxies in Arp 299.
The National Science Foundation’s Very Long Baseline Array (VLBA) then revealed a new, distinct source of radio emission from the same location.
Used the Nordic Optical Telescope on the Canary Islands and NASA’s Spitzer space telescope, the researchers followed the object’s infrared emission. Continued observations with the EVN, VLBA and other radio telescopes, carried out over nearly a decade, showed the source of radio emission expanding in one direction, just as expected for a jet.
Observing the event
Only a small number of these stellar deaths, known as tidal disruption events, have ever been detected. Theorists suggest that material pulled from the star forms a rotating disk around the black hole, emitting intense X-rays and visible light.
It also launches jets of material outward from the poles of the disk at nearly the speed of light.
Miguel Perez-Torres, from the Astrophysical Institute of Andalucia, Spain, said: “Never before have we been able to directly observe the formation and evolution of a jet from one of these events.
“Tidal disruption events can provide us with a unique opportunity to advance our understanding of the formation and evolution of jets in the vicinities of these powerful objects.”