It’s the most accurate calculation to date.
73 million light-years away sits a supermassive black hole at the center of a galaxy known as NGC 1332. Thanks to groundbreaking observations, an international team of scientists, including Rutgers associate professor Andrew J. Baker, has measured its mass with the highest accuracy to date.
Supermassive black holes, located at the center of large galaxies, form after a supernova, or exploding star, collapses in on itself. In fact, many scientists believe that these black holes formed at the same time as their host galaxy. Supermassive black holes are so immensely dense that their gravity pulls in anything that’s close, including light, and they grow by gobbling up gas, stars, and other black holes.
However, "just because there's a black hole in your neighborhood, it does not act like a cosmic vacuum cleaner," explained Baker in a Rutgers press release. Stars can travel close to black holes, but as long as they are in stable orbits and moving fast enough, they won’t fall victim to it.
Scientists think that every massive galaxy, like our Milky Way, has an enormous black hole at its center.
Current research suggests that the growth of galaxies and the growth of their black holes are inherently linked, and that the ratio of a black hole’s mass to a galaxy’s mass is important in understanding what they are both made of.
If we want to understand how galaxies form and evolve, we need to understand supermassive black holes. "The ubiquity of black holes is one indicator of the profound influence that they have on the formation of the galaxies in which they live," said Baker.
Part of understanding supermassive black holes comes from measuring their exact mass, which allows scientists to determine whether a black hole is growing faster or slower than its galaxy.
To measure NGC 1332’s central black hole, scientists used the Atacama Large Millimeter/submillimeter Array (ALMA), located in Chile, which is the world's largest astronomical project. It is a telescope with 66 radio antennas that sit about 16,400 feet above sea level. The researchers collected ALMA observations of carbon monoxide emissions from a large disc of cold gas orbiting the black hole, known as an accretion disc, and measured the speed of the gas.
The results, published today (May 5) in the Astrophysical Journal Letters, show that the supermassive black hole is 660 million times more massive than our sun, and its cloud of gas circles it at approximately 1.1 million miles per hour.
Combined image of NGC 1332 shows the central disk of gas surrounding the supermassive black hole at the center of the galaxy. Photo credit: A. Barth (UC Irvine), ALMA (NRAO/ESO/NAOJ); NASA/ESA Hubble; Carnegie-Irvine Galaxy Survey
"This has been a very active area of research for the last 20 years, trying to characterize the masses of black holes at the centers of galaxies," said Baker. "This is a case where new instrumentation has allowed us to make an important new advance in terms of what we can say scientifically."