Astronomers determined that a black hole, about 73 million light-years from Earth, weighs the equivalent of 664 million solar suns, according to a study published on Thursday in the Astrophysical Journal Letters.

The phenomenon was measured by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, through analysis made to the galactic gases inside the deep gravitational well of the black hole, as reported by Discovery News.

Astronomers found black hole with the mass of 664 million suns. Credit: Astronomy

“To calculate the mass of a black hole in a galaxy’s center, we need to measure the speed of something orbiting around it,” said study lead Aaron Barth, of the University of California. “For a precise measurement, we need to zoom in to the very center of a galaxy where the black hole’s gravitational pull is the dominant force,” he explained.

According to Professor Andrew Baker, who also participated in the study, trying to characterize the masses of black holes at the centres of galaxies has been a very active area of research for the last 20 years. In the particular case, the new instrumentation has allowed them to make an important new advance in terms of what they can say scientifically, according to Baker.

Supermassive black hole

Black holes are hard to spot and to measure, one way to do it is by measuring the emissions of the hot gas trapped in a black hole’s accretion disk and the other is to see how a black hole’s mass will warp spacetime, bending or lensing light around it.

For the NGC 1332, the official name for the black hole, cold molecular gas was seen in its vicinity. Researchers determined the distance of the gas cloud from the black hole and used ALMA to clock its speed. This provided a pretty accurate measurement and as a conclusion, the phenomenon was classified in the heavyweight division of supermassive black holes.

A more accurate measurement system

Other measures used to be made by the Hubble Space Telescope, but although this has offered the capability to calculate the mass of some black holes, by doing it with hot accretion disks, this was not completely accurate and offered uncertainty in visible light measurements.

Instead, the emissions from cold molecular gas in extended disks originated from far more quiescent environments, provided researchers the latest tool for a more precise measurement for the black holes.

Source: Astrophysical Journal Letters