Extremely fine measurements of motion in orbiting supermassive black holes – Space Daily
Approximately 750 million light years from Earth lies a gigantic, bulging galaxy with two supermassive black holes at its center. These are among the largest black holes ever found, with a combined mass 15 billion times that of the sun. New research from Stanford University, published June 27 in Astrophysical Journal, has used long-term observation to show that one of the black holes seems to be orbiting around the other.
If confirmed, this is the first duo of black holes ever shown to be moving in relation to each other. It is also, potentially, the smallest ever recorded movement of an object across the sky, also known as angular motion.
“If you imagine a snail on the recently discovered Earth-like planet orbiting Proxima Centauri – a bit over four light years away – moving at one centimeter a second, that’s the angular motion we’re resolving here,” said Roger W. Romani, professor of physics at Stanford and co-author of the paper.
The team also included researchers from the University of New Mexico, the National Radio Observatory and the United States Naval Observatory.
The technical achievements of this measurement alone are reason for celebration. But the researchers also hope this impressive finding will offer insight into how black holes merge, how these mergers affect the evolution of the galaxies around them and ways to find other binary black-hole systems.
Over the past 12 years, scientists, led by Greg Taylor, a professor of physics and astronomy at the University of New Mexico, have taken snapshots of the galaxy containing these black holes – called radio galaxy 0402+379 – with a system of ten radio telescopes that stretch from the U.S. Virgin Islands to Hawaii and New Mexico to Alaska. The galaxy was officially discovered back in 1995. In 2006, scientists confirmed it as a supermassive black-hole binary system with an unusual configuration.
“The black holes are at a separation of about seven parsecs, which is the closest together that two supermassive black holes have ever been seen before,” said Karishma Bansal, a graduate student in Taylor’s lab and lead author of the paper. With this most recent paper, the team reports that one of the black holes moved at a rate of just over one micro-arcsecond per year, an angle about 1 billion times smaller than the smallest thing visible with the naked eye. Based on this movement, the researchers hypothesize that one black hole may be orbiting around the other over a period of 30,000 years.
Two holes in ancient galaxy
Although directly measuring the black hole’s orbital motion may be a first, this is not the only supermassive black-hole binary ever found. Still, the researchers believe that 0402+379 likely has a special history.