A team of astronomers led by researchers from the University of Birmingham, University College London and King’s University Belfast has discovered one of the most dramatic black hole “openings” ever seen. They will present their findings at the 2023 National Astronomy Meeting in Cardiff on Tuesday, July 4th. The study will also be published Monthly Notices of the Royal Astronomical Society.

J221951-484240, known as J221951, is one of the brightest transits (astrophysical objects that change their brightness within a short period of time) ever recorded. It was discovered in September 2019 by astronomer Dr Samantha Oates of the University of Birmingham and her team while searching for electromagnetic light from a gravitational wave event. The team used ultraviolet and optical telescopes at the Neil Gehrels Swift Observatory to search for a kilobyte that is the signature of a neutron star merging with another neutron star or black hole. Kilonova usually appears blue, then fades and becomes redder within a few days. Instead, they found something more unusual: J221951. It looked temporary blue, but didn’t change color or fade away as quickly as a kilonova would.

Several telescopes were used to observe J221951 and determine its nature, including NASA’s ESO facilities such as the Swift/UVOT and Hubble Space Telescopes, the South African Large Telescope and the Very Large Telescope, and the GROND instrument at the MPG/ESO 2.2-metre observatory. .La Silla.

The spectrum of J221951 obtained by the Hubble Space Telescope refused to link J221951 to a gravitational wave event. Dr. By examining the light spectrum of J221951, Oates and his team were able to determine that the source is about 10 billion light-years away, in contrast to the gravitational wave signal detected 0.5 billion light-years away. It shines so brightly from such a great distance, making J221951 one of the brightest transitions ever detected.

Evidence suggests that J221951 formed as the result of a supermassive black hole feeding the surrounding material very quickly. The red galaxy was observed at the location of J221951 before it was discovered, and the location of J221951 was consistent with the center of the galaxy where a massive black hole would naturally be found. It started to glow very suddenly about 10 months before it was first detected, meaning the black hole started feeding very quickly after being quiet for a while. The UV spectrum exhibits absorption properties consistent with the material being pushed outward with a large release of energy. This, combined with the high luminosity, makes this one of the most dramatic black hole “openings” ever seen.

The team identified two possible mechanisms that could explain this extreme supermassive black hole feeding. First, it may have been caused by a tidal collapse event, the collapse of a star as it passed by the supermassive black hole at the center of its galaxy. Second, it may have been created by an active galactic nucleus that “changed state” from dormant to active. J221951 will then signal that the dormant black hole at the center of the main galaxy is starting to feed on material from the accretion disk.

Dr Matt Nicholl, a member of the team from King’s University Belfast, said: “Our understanding of the different things supermassive black holes can do has been greatly expanded in recent years, thanks to the fragmentation of stars and the massive coalescence of black holes of variable luminosity.” “J221951 is one of the most extreme examples of black holes to surprise us. Continuous monitoring of J221951 to determine its overall energy release may allow us to determine whether it is a tidal collapse of a rapidly spinning black hole star or a new type of key AGN.”

Dr N Paul Quinn, another member of the Mallard Space Sciences Laboratory team at University College London, said: “The important discovery was that the Hubble ultraviolet spectrum ruled out a galactic origin. This shows how important it is to protect the Space UV Spectrograph for the future.”

Dr Samantha Oates adds: “In the future, we may gain important clues to distinguish a tidal disruption event from active galactic core scenarios. For example, if J221951 is associated with an AGN opening, we might expect J221951 to stop dimming and increase again, whereas if J221951 is a tidal disruption event “We can expect it to continue to decline. We will need to continue to monitor J221951 over the next few months or years to catch its late behavior.” Source