Researchers at the University of Alberta have discovered the first of what they say could be many "stealth" black holes in the universe, which they found hiding in a well-known area of space.
The stealth black hole is located near a small star, and was difficult to detect because of its modest appetite, according to a news release from the U of Alberta researchers. Originally discovered two decades ago, the object was initially thought to be a distant galaxy because of its bright radio wave emissions and tiny X-ray profile. However, the U of Alberta study has revealed it to be a small black hole that was consuming material at a "paltry" rate, leading to suggestions that there may be many more such black holes scattered throughout the galaxy.
While most black holes emit large amounts of X-ray radiation from the material they consume, the stealth black hole was a mere blip because it was "eating" material at a slower rate, the researchers found. "Usually we find black holes when they are pulling in lots of material," said study lead author Bailey Tetarenko, a Ph.D candidate at the University of Alberta. Tetarenko explained that material burns up as it's pulled into a black hole, and that destructive force typically gives off a bright X-ray signature for astronomers to detect.
But that wasn't the case with this discovery, Tetarenk said. "This one is so quiet that it's practically a stealth black hole."
The black hole, called VLA J2130+12. is a few times the mass of our own sun, and is very slowly feeding on a small star nearby.
The U of Alberta study suggests there could be many more stealth black holes hiding in the blackness of space.
"Unless we were incredibly lucky to find one source like this in a small patch of the sky, there must be many more of these black hole binaries in our galaxy than we used to think," co-author Arash Bahramian said in a news release.
The findings are published in the latest edition of The Astrophysical Journal.
