Black Hole Trio May Cause Space Time Ripples
Three closely orbiting supermassive black holes have been discovered billions of light years away. Groups like this are theorized to be the source of gravitational waves in the Universe, according to the theory of General Relativity.
"Using the combined signals from radio telescopes on four continents we are able to observe this exotic system one third of the way across the Universe," research leader Robert Deane said in a statement. "What remains extraordinary to me is that these black holes, which are at the very extreme of Einstein's Theory of General Relativity, are orbiting one another at 300 times the speed of sound on Earth."
The discovery is detailed in a study published in the journal Nature.
Matt Jarvis of Oxford University, an author of the study, explains that General Relativity predicts merging black holes are the source of "gravitational waves," or ripples, in spacetime throughout the Universe.
"In this work we have managed to spot three black holes packed about as tightly together as they could be before spiralling into each other and merging," he said in a statement. "The idea that we might be able to find more of these potential sources of gravitational waves is very encouraging as knowing where such signals should originate will help us try to detect these 'ripples' in spacetime as they warp the Universe."
According to the study, the two inner black holes of the triple system are emitting massive jet-streams of gas and radiation - as is traditional for super massive black holes at the center of a galaxy. The resulting helical stream that the orbiting streams formed was picked up by a Very Long Baseline Interferometry (VLBI) technique, which combines the signals from large radio antennas separated up to 10,000 kilometers apart. The VLBI technique can reportedly see deep space details 50 times finer than the Hubble Space Telescope.
"VLBI is widely recognized as one of the best ways to confirm close-pair black hole systems, but the main difficulty has always been pre-selecting the most promising candidates," explained co-author Zsolt Paragi from the Joint Institute for VLBI in Europe (JIVE). "Our research shows that close-pair black holes may be much more common than previously thought, although their detection require extremely sensitive and high-resolution observations."
The study was published in Nature on June 25.