Jewish University finds first evidence of delayed radio eruptions after the star was destroyed by the black hole

A team of researchers at the Hebrew University of Jerusalem (HUJI) led by Dr. Assaf Horesh has discovered the first evidence of radio missiles emitted only long after a star is destroyed by a black hole. Published periodically Nature Astronomy, the discovery relied on ultra-powerful radio telescopes to study these catastrophic cosmic events in distant galaxies called Tidal Events (TDEs). While researchers knew that these events caused the release of radio missiles, this latest discovery saw those missiles being emitted months or even years after stellar disruption. The team was led by Dr. Horesh of the Racah Institute of Physics in Hebrew along with NASA Swift Space Telescope Director Professor Brad Cenko and Dr. Iair Arcavi of Tel Aviv University.

“According to existing theories about how these events occur, if no radio broadcast was discovered immediately after the outage, there is no expectation that one will appear later,” says Dr. Horesh. “However, we decided to make one last radio observation six months after the star’s destruction, and surprisingly we discovered bright radio emissions. Once we discovered this delayed radio explosion, we continued to collect data for a year, In addition, we found a second delayed eruption, four years after the initial discovery of stellar perturbation, the first such discovery of such delayed radio eruptions in such events, when a star is interrupted by a black hole. “

The eruptions are believed to be caused by a huge jet of speed released when the star is destroyed and sucked into the black hole or as a result of the external explosion of the debris from the explosion.

The analysis of the delayed radio eruptions led the research team to several conclusions.

First, they now believe that new models need to be developed to explain such a long delay in radio signal transmission. Second, such delayed radio signals may be a common phenomenon, but to find more of them, teams will need to stay focused on observations around the affected areas long after the initial outage. Third, it is possible that a substantial amount of stellar debris will eventually accumulate (pull) into the black hole, but only long after the star’s destruction.

“What led to the delay and what exactly is the physical process responsible for such a late broadcast are still open questions,” says Dr. Horesh. “In light of this discovery, we are actively looking for more such delayed radio eruptions in other tidal disruption events.”

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