The universe's supermassive black holes are growing faster than their host galaxies, new research by Penn State researchers has found out.
Scientists have been observing galaxy formation and their central supermassive black holes. The mass of these black holes are millions to billions of times the Sun's mass. Researchers, in general, believed that black holes and their parent galaxies grow approximately at the same rate.
The recent paper, however, showed that supermassive black holes located at the center of massive galaxies are growing faster than their hosts.
Scientists Reconstruct A Primeval Race To Understand The Phenomena
The study used data collected from the Hubble Space Telescope, NASA's Chandra X-ray Observatory, and other observatories and telescopes to understand the growth rate of black holes in galaxies located farther away in the universe.
Yang also added that the in-depth information enabled the researchers to analyze how black holes evolved with their parent galaxies, a process that started 12 billion years ago in a young universe.
“We are trying to reconstruct a race that started billions of years ago,” said lead study author Guang Yang. “We are using extraordinary data taken from different telescopes to figure out how this cosmic competition unfolded.”
Growth Rate Comparison Between Massive Galaxies And Their Supermassive Black Holes
The scientists looked into the ratio between the growth rate of the host galaxy and the supermassive black hole. The ratio has been believed to be constant and that it is applicable for all galaxies. The team, however, found that the ratio was a lot higher for bigger galaxies.
Researcher Fabio Vito added that the case is rather different for small and big galaxies. In bigger galaxies, the supermassive black holes win while in smaller galaxies, black holes lose to their host. Yang said that if a galaxy is 10 times more massive than another galaxy, the black hole's growth rate is 100 times faster compared to the black hole in the second galaxy.
The researchers have hypothesized that bigger galaxies are more efficient at inputting cold gas to the supermassive black holes at their center in comparison to smaller ones.
Using the growth history of black holes, the researchers also predicted the mass of black holes in the present cosmic epoch, which denotes the current timeline. The figure predicted by the team matched the big galaxies' direct measurements, which indicates that their predictions were successful in recovering the whole history of the growth of black holes in the universe.
The study linking black-hole growth with the host galaxy will be published in the April 2018 issue of the journal Monthly Notices of the Royal Astronomical Society.
