Black Hole Continues Emitting Energy Years After Consuming Star
Astronomers observe prolonged energy emissions from black hole AT2018hyz, years after it consumed a star, challenging existing theories on tidal disruption events.
In October 2018, astronomers observed a supermassive black hole, designated AT2018hyz, located approximately 665 million light-years from Earth, consuming a nearby star in an event known as a tidal disruption event (TDE). Initially, the black hole exhibited no significant radio emissions. However, nearly three years later, in June 2021, researchers detected a sudden and dramatic increase in radio wave emissions from AT2018hyz, marking it as one of the most radio-luminous TDEs ever observed.
Yvette Cendes, an astrophysicist at the University of Oregon, led the study and noted the unusual nature of this delayed emission.
The research team utilized multiple radio telescopes, including the Very Large Array in New Mexico and the MeerKAT radio telescope in South Africa, to monitor the black hole's activity. Their observations revealed that the energy emitted from AT2018hyz has continued to rise sharply over the years, now being 50 times brighter than when originally detected in 2019.
Calculations suggest that the radiation is being emitted as a single jet, potentially explaining why it wasn't initially detected if the jet wasn't aimed towards Earth. The energy outflow is estimated to be on par with a gamma-ray burst, placing it among the most powerful single events ever detected in the universe.
This unprecedented behavior challenges existing theories on TDEs and suggests that delayed energy emissions may be more common than previously thought. The team continues to monitor AT2018hyz to further understand the mechanisms behind this phenomenon and is investigating other black holes for similar delayed emissions.