Astrophysicists first observed an event that after it tore a star into pieces with tidal force, matter near the black hole was strongly ejected. Generally, the radiation brightness emitted by accretion disk or jets increases almost immediately after they are replenished with newly absorbed celestial matter.
Due to the damage of tidal forces, the matter of the star spreads everywhere. A black hole jet is above and below the image. As an artist TDE
When a star or other object is very close to a larger object (such as a black hole), they lose integrity at some point. The gravity of the "guest" itself no longer condenses its matter together - the so-called tidal destruction event (or flash) occurred (TDE) . The gravitational force of a black hole acts too differently on one side of the "careless" star closest to it than on the other.
2018, the supernova automatic search (ASAS-SN) telescope detected TDE in an unnamed galaxy about 665 million light years from the earth (2MASS J10065085+0141342). A small star with a mass of about one tenth of the sun is too close to supermassive black hole . The index of this event is AT 2018hyz. After careful observation in various radiation ranges for several months, no abnormalities were found. has only a few nuances from other similar TDE, otherwise the flash will fade as usual.
In the next few years, AT 2018hyz was regularly checked in a routine sky survey, but there were no signs of abnormal behavior. Everything changed in June 2021. According to Yvette Cendes, an assistant researcher at the Smithsonian Astrophysical Observatory, she and her colleagues had to take urgent measures to avoid missing the moment. The "sudden awake" TDE was discovered in New Mexico, USA. The ultra-large array antenna (VLA) radio telescope complex. The scientists immediately issued a request for special access to the instruments of other telescopes (DDT) to study unique events in different spectra .
Astronomers around the world responded quickly: ALMA (Chile ), MeerKAT (South Africa) and ATCA (Australia) radio telescope complex, as well as Neil Gehrels Swift Observatory and Chandra Space X-ray Observatory, all observed abnormally delayed activities. AT 2018hyz. Researchers published a detailed description of observations and data analysis results in "Journal of Astrophysics".
An interesting picture appeared. TDE 970 days later, due to reasons not fully understood, the accretion disk of the black hole associated with AT 2018hyz began to eject matter. Moreover, it flows out to the surrounding space at half the speed of light. This is unusual for two reasons. First, TDE brightness reaches its maximum almost immediately after the event starts, and then gradually decreases after hundreds of days, but not more than two years. Secondly, in this process, some of the matter from the destroyed star can be ejected, but its speed does not exceed 20% of the speed of light.
Considering that in the past three years since AT 2018hyz was registered to re-activity, no star fell on this black hole, and the nature of the event has raised questions. Astrophysicists have proposed several hypotheses and performed corresponding simulations, but still do not exactly match the observations. Generally speaking, the explanation comes down to the mass of the destroyed star entering the accretion disk causing some unstable process or fluctuation. After nearly a thousand Earth days, they are poured into a bubble or jet stream and thrown out of the black hole.
Another idea is that the jet is there from the beginning, but collapses stars' matter is immediately scattered in the surrounding space, shielding the relativistic jet. Admittedly, this option is least inconsistent with 2018-19 and recent observations.