Astronomers have discovered a hidden jet of an intermediate-mass black hole
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- Astronomers have discovered a hidden jet of an intermediate-mass black hole
Astronomers using the Large Antenna Array of the US National Science Foundation (NSF VLA) have discovered an unusual powerful radio burst, indicating a rare cosmic event — the absorption of a star by an intermediate-mass black hole. The results were reported by the magazine on July 8. Phys.org .
The event, designated AT2019ijn, initially manifested itself as a bright blue flash in the optical range, which quickly peaked and faded more slowly than usual. However, in the course of subsequent observations, it turned out that the radio emission continued to increase for almost two years before a slow decline began, lasting at least four years.
The researchers concluded that they had detected a tidal disruption event, a process in which a star gets too close to a black hole and is torn apart by its gravity. The dynamics of the flare indicates that the object belongs to the class of intermediate-mass black holes, which are the "missing link" between stellar-mass black holes and supermassive giants in the centers of galaxies. Such objects are extremely difficult to detect, and scientists have long been looking for ways to identify them.
"The AT2019ijn event suggests one of these ways: if an intermediate-mass black hole releases a jet (jet. — Ed.), directed not directly at the Earth, the event at first seems modest, but then abruptly becomes brighter in the radio range as the jet slows down. <...> At a frequency of 3 GHz, the radio signal turned out to be more than 100 times more powerful than radiation from known supernovae at similar stages," it follows from the material.
To study the phenomenon, scientists combined optical survey data with radio emissions recorded by the NSF VLA, the Australian ASKAP telescope and the Indian giant Metrewave radio telescope. The simulation showed that the radio emission comes from matter moving at a speed close to light. The authors of the work believe that it was a narrow relativistic jet that was observed from the side, which explains the delay of the radio flare.
According to the publication, the discovery expands the possibilities of searching for hidden black holes and proves that many unusual optical transients may be part of a family of events related to black holes that were previously ignored due to the late appearance of the radio signal. Further observations will help scientists understand how often intermediate-mass black holes destroy stars and under what conditions they create powerful jets.
Phys.org On July 6, he reported the discovery of a new type of flare in black holes. Scientists have studied the galaxy SDSS J110546.07+145202.4 and found out that the radiation source is located near its central black hole. According to the study, in the case of this particular object, the radio signal not only increased by more than 20 times, but also showed no signs of weakening for several years.
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