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SOUTHAMPTON, United Kingdom — In June 2015, astronomers observed that V404 Cygni — a black hole in the Milky Way galaxy about 7,800 light years from earth — was emitting brief flashes of red light with a luminosity in the range of 3.846×1029 watts (1000 times brighter than our sun).
Astronomers from the University of Southampton have released their findings in the journal Monthly Notices of the Royal Astronomical Society, positing that the sudden intense burst of radiation from V404 Cygni was the result of an orbiting star being devoured by the supermassive black hole.
"These red flashes were found to be strongest at the peak of the black hole's feeding frenzy," said Dr. Poshak Gandhi, lead author of the study and Associate Professor of University of Southampton's Astronomy Group in a university release. "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."
Eruptions of this kind are few and far between, leaving astronomers limited opportunities to study them. V404 Cygni's last eruption occurred in 1989, and as things are, there's no telling when the next one will come. Though bright, these flashes were quite brief, some lasting for less than 1/40 of a second, so recording them called for the use of an ULTRACAM high frame-rate camera in conjunction with the William Herschel Telescope, an observatory in the Canary Islands. Researchers have been combing through the heaps of data they obtained in June for the past eight months and are just now presenting their findings.
The study also lends more credence to a theory on the origins of intragalactic cosmic radiation. Cosmic rays are constantly bombarding the Earth, many of them coming from our own sun, supernovae of galactic neighbors, and quasars in the far reaches of space, most of which is blocked by Earth's magnetic field. Up until now, the prevailing theory as to the source of cosmic radiation from within our own galaxy was that it came mostly from supernovae. This explains much of the radiation, but not all of it. This study supports a theory that points to another source, that being the ejection of high-energy particles from a black hole, that, to put things in layman's terms, has bitten off more than it can chew.
Astrophysicist Andrew Taylor of the Dublin Institute for Advanced Studies said to ScienceMag.org, "It's very exciting. This has probably shaken the field quite a lot. People will need to reassess their models."
Dr. Gandhi believes that the recent eruption has awakened astronomers worldwide to the need for collaboration in cases like the July 2015 eruption. In the University of Southampton release, Gandhi said, "Their short durations, and strong emissions across the entire electromagnetic spectrum, require close communication, sharing of data, and collaborative efforts amongst astronomers. These observations can be a real challenge, especially when attempting simultaneous observations from ground-based telescopes and space satellites.”
Sean Stoker is a journalism student at UVU interning for KSL.com. He runs a YouTube channel called QuestSeans. Follow him on Twitter @theroyalthey