This is a big astrophysical find, literally big! The Chandra X-Ray telescope has detected the signature of a supermassive black hole by observing the hot gases falling into it. The estimated mass of the black hole is a huge 2 Billion times the mass of the Sun!
The compact object lies at the heart of the galaxy known as NGC 3115, located at a distance of 32 million light-years away from Earth, making this the closest billion-solar-mass object to Earth. Astronomers have long been interested in the activity in this region, especially the gas falling into the central object. There have been various observations in the various frequencies, but this is only the first time when the X-Ray signatures have been clearly observed. The Chandra data suggests a huge mass for the black hole, given the temperature of the glowing gas falling into it. Only if the gas glows extremely intensely, does it give off X-Rays. NGC 3115 is about a million times brighter in X-Rays than in visible light.
How They Found Out the Mass
There is a term, called Bondi radius, named after the astrophysicist Hermann Bondi, which describes how the gas is affected by the black hole gravity. It is defined as the distance at which the gravity first starts dominating the random kinetic motion of the gas and the gas starts spiraling into the black hole.
The data from the Chandra telescope suggests that the Bondi Radius is 700 light years away from the black hole!! In comparison, the closest star to Earth, after the Sun, is about 4 light years away. This gives an estimate of the mass of the black hole and the calculation suggests 2 billion solar masses!!
This finding is not only one for public consumption, but also scientific fodder. It may help to explain how matter flows into a black hole, as a tremendous amount of data is available due to the luminosity of the black hole.
It also brings up questions. Scientists still don’t know how such extremely massive black holes stay dim. As Dr. Jimmy Irwin, assistant professor of University of Alabama’s Physics Department says:
A leading mystery in astrophysics is how the area around massive black holes can stay so dim, when there’s so much fuel available to light up.
It is often said that astronomy is a humbling science. This just confirms that saying.