spaceSpace and Physics

Red "Flashes" Spotted From Black Hole Devouring A Star


Jonathan O'Callaghan

Senior Staff Writer

441 Red "Flashes" Spotted From Black Hole Devouring A Star
ESO/L. Calçada

There’s something strange in our neighborhood. But it’s probably best to call a team of astronomers, rather than a group of paranormal-chasing scientists, to solve this mystery.

So, what’s going on? Well, research led by the University of Southampton spotted red “flashes” coming from a relatively near black hole, V404 Cygni, 7,800 light-years from Earth. The flashes occurred in June 2015 over the course of two weeks, when the black hole went through a burst of activity.


A study detailing the flashes was published in the journal Monthly Notices of the Royal Astronomical Society (which, amusingly, is neither monthly nor does it carry the notices of the Royal Astronomical Society).

The red color is due to the speed of the bursts, which was captured by the ULTRACAM fast imaging camera on the William Herschel Telescope in La Palma, on the Canary Islands. Each flash was incredibly quick, lasting just 1/40th of a second, 10 times faster than the blink of an eye. But each packed a powerful punch, with a power output equivalent to about 1,000 Suns.

“The very high speed tells us that the region where this red light is being emitted must be very compact,” lead author on the study Dr. Poshak Gandhi said in a statement. “Piecing together clues about the color, speed, and the power of these flashes, we conclude that this light is being emitted from the base of the black hole jet.”

An animation of one of the flashes is shown above.


The burst of activity responsible for the unpredictable flashes, the last of which occurred in 1989, was caused by the black hole devouring a nearby star. It’s unable to “eat” all of the material it takes on, so some of it is fired back into space as jets. And at the base of the jets, these incredibly short but incredibly bright red flashes were produced.

Exactly how the jets are produced is not fully understood, although magnetic fields are thought to play a part. Perhaps these flashes could provide some answers, though, and they may also help reveal how black holes eat material and spew out jets. Indeed, this outburst was one of the brightest seen in recent years.

“We speculate that when the black hole was being rapidly force-fed by its companion orbiting star, it reacted violently by spewing out some of the material as a fast-moving jet,” said Dr. Gandhi. “The duration of these flashing episodes could be related to the switching on and off of the jet, seen for the first time in detail.

“The 2015 event has greatly motivated astronomers to coordinate worldwide efforts to observe future outbursts.”.


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