A massive black hole at the centre of a distant galaxy has the mass of 140 million Suns, scientists have found. The black hole is in the heart of galaxy NGC 1097, which is 47 million light-years away from Earth. The distance is too far for scientists to determine the mass of the black hole by the movement of the stars around it.
But by tracking the movements of two types of molecular gases around the galaxy’s centre, researchers using the Atacama Large Millimetre/submillimetre Array in Chile (ALMA) were able to figure out the black hole’s gravitational pull. Their results show that the black hole is significantly larger than the one at the centre of the Milky Way (140 million Suns in mass versus the Milky Way’s 4 million or so).
The ALMA telescopes tracked the radiation emitted from the two gases, hydrogen cyanide and formyl cation, as they swirled around the galaxy. The gases don’t interact strongly with environmental conditions within the galaxy, such as ionised gas flowing inward or outward. This means the gases paint an accurate picture of the effects of gravity’s pull alone.
With just two hours of observational data, the researchers learned enough about the distribution and velocities of those gases to fit them to a model and calculate the pull of the galaxy’s core black hole, ‘Space.com’ reported. The mass of a central black hole affects the physical properties of its host galaxy, and recent work has shown that those effects are different for different types of galaxies, said study lead author, Kyoko Onishi, a doctoral student at The Graduate University for Advanced Studies in Japan.
The research was published in The Astrophysical Journal.