Mass Measurement Of Behemoth Black Hole Reveals New Science

By pegging the core mass of a distant spiral galaxy at 140 million times that of sun, researchers have shown a new method to use make such measurements.

Using the Atacama Large Millimeter/Submillimeter Array (ALMA) astronomers measured the black hole powering NGC 1097, a barred spiral galaxy located about 45 million light years away. The measurement of 140 million solar masses is said to be highly precise given the method of measurement. The massive size of NGC 1097 dwarfs the central black hole powering the Milky Way's central. Sagittarius A^* which powers the Milky Way is said to be around 4 million solar masses.

The measurements were made by researchers at the Graduate University for Advanced Studies in Japan. They used the distribution and motion of hydrogen cyanide and formylium in the area around NGC 1097's center. The distribution data when used in several models revealed the best fit scenario for 140 solar masses.

"This is the first use of ALMA to make such measurement for a spiral or barred spiral galaxy. When you look at the exquisitely detailed observations from ALMA, it's startling how well they fit in with these well tested models. It's exciting to think that we can now apply this same technique to other similar galaxies and better understand how these unbelievably massive object affect their host galaxies," the paper's co-author Kartik Sheth said.

Existing techniques to estimate black hole mass rely on movement of celestial objects including stars and radio sources. Movement of ionized gas is also used for elliptical galaxies. The ALMA method could be the best technique for spiral galaxies.