Certainly one of the brightest transient events is the results of a supermassive black hole starting to feast on surrounding matter leading to one of the dramatic “switching on” events ever seen.
Transients are astronomical events or objects that change in brightness over short periods of time, and the one powered by this greedy black hole — J221951 — is certainly one of the brightest transients ever recorded. The position of the black hole corresponds with the middle of a previously observed galaxy, just where a supermassive black hole could be expected to take a seat. Nonetheless, astronomers still aren’t sure exactly what’s causing the transient event witnessed in J221951 .
“Our understanding of the various things that supermassive black holes can do has greatly expanded in recent times, with discoveries of stars being torn apart and accreting black holes with hugely variable luminosities,” team member and University of Belfast astronomer Matt Nicholl, said in an announcement. “J221951 is one of the extreme examples yet of a black hole taking us by surprise.”
Related: Star survives spaghettification by black hole
The character of what the supermassive black hole situated around 10 billion light-years away is consuming is currently unknown, however it is feasible that J221951 represents a star that has ventured too near the black hole being violently ripped apart by tidal forces arising from its immense gravity in a process called spaghettification.
This occurrence, called a tidal disruption event (TDE), would see a few of the stellar material from the destroyed star fall to the surface of the black hole while other matter is funneled to the poles of the black hole before being blasted out at near light-speeds, generating intense electromagnetic radiation.
The spaghettification of an unlucky star is not the only possible mechanism that might be causing the black hole in query to present rise to this brilliant transient event, nevertheless. One other possibility is that J221951 is the results of the nucleus at the guts of a galaxy switching from a dormant to an lively state.
Lively galactic nuclei (AGNs) are brilliant areas at the guts of galaxies that blast out enough light to drown out the combined light of each star in the remainder of that galaxy. Also they are powered by supermassive black holes.
“Continued monitoring of J221951 to work out the entire energy release might allow us to work out whether this can be a tidal disruption of a star by a fast-spinning black hole or a brand new type of AGN turn on,” Nicholl added.
Watching the dramatic “switching on” at the guts of a galaxy
Kilonovas are a style of transient event that happens throughout the merger of two neutron stars or a neutron star and a black hole, which releases brilliant bursts of electromagnetic radiation. Kilonovas initially have a blue coloration, then fade to red over a period of several days. The transient J221951 also appeared blue, however it didn’t change to red or fade rapidly as a kilonova would. The character of this transient was determined by follow-ups with space-based facilities just like the Hubble Space Telescope and ground-based observatories just like the Very Large Telescope (VLT) situated within the Atacama Desert of Northern Chile.
“The important thing discovery was when the ultraviolet (UV) spectrum from Hubble ruled out a galactic origin. This shows how vital it’s to keep up a space-based UV spectrograph capability for the long run,” team member and Mullard Space Science Laboratory at University College London researcher Paul Kuin said.
With a source situated 10 billion light-years away, the team realized that J221951 have to be certainly one of the brightest events ever seen. They may now work to higher understand its cause.
“In the long run, we are going to have the option to acquire vital clues that help distinguish between the tidal disruption event and lively galactic nuclei scenarios,” Oates said. “As an illustration, if J221951 is related to an AGN turning on, we may expect it to stop fading and to extend again in brightness, while if J221951 is a tidal disruption event, we might expect it to proceed to fade.
“We’ll must proceed to observe J221951 over the following few months to years to capture its late-time behavior.”
The team presented their findings on Tuesday, July 4, on the National Astronomy Meeting 2023 in Cardiff, U.K.