Scientists Create "Scale" to Weigh Black Holes a Billions Times More Massive than the Sun

And you thought you had weight problem! How do you weigh the biggest black holes in the universe, supermassive black holes hat are billions of times more massive than the sun? (image shows objects being pulled into a black hole).

By measuring a peak in the temperature of hot gas in the center of the giant elliptical galaxy NGC 4649, scientists have determined the mass of the galaxy’s supermassive black hole. NGC 4649 is one of the largest in the local universe with a mass about 3.4 billion times that of the sun, about 1,000 times bigger than the black hole at the center of our galaxy.

UC Irvine scientists and other astronomers have developed the new technique using data from NASA’s Chandra X-ray Observatory. The method, applied for the first time, gives results that are consistent with a traditional technique based on observing the motions of stars or of gas in a disk near such large black holes.

“This is tremendously important work since black holes can be elusive, and there are only a couple of ways to weigh them accurately,” said Philip Humphrey, leader of the study and an assistant project scientist in the Department of Physics and Astronomy at UCI. “It is reassuring that two very different ways to measure the mass of a big black hole give such similar answers,” Humphrey said.

NGC 4649 is now one of only a handful of galaxies for which the mass of a supermassive black hole has been measured with two different methods. The new technique takes advantage of the gravitational influence the black hole has on the hot gas near the center of the galaxy. As gas slowly settles towards the black hole, it gets compressed and heated.

This effect was predicted by two of the co-authors – Fabrizio Brighenti from the University of Bologna, Italy, and William Mathews from the University of California, Santa Cruz – almost 10 years ago, but this is the first time it has been seen and used.

“Monster black holes such as this one power spectacular light shows in the distant, early universe, but not in the local universe,” Humphrey said. “So, we can’t wait to apply our new method to other nearby galaxies harboring such inconspicuous black holes.”

Posted by Casey Kazan.

Source: http://today.uci.edu/news/release_detail.asp?key=1796