Researchers may have found a solution to a mysterious quasar sequence that has been baffling scientists.
Quasars are supermassive black holes that exist at the center of galaxies, Carnegie Science reported. The illuminate the electromagnetic spectrum by "rapidly accreting matter into their gravitationally inescapable centers."
Researchers may have finally solved a quasar mystery that has been puzzling scientists for two decades. The study showed the most observed quasar phenomena could be unified with two quantities; one which shows how efficiently the hole is being fed and one reflecting the viewing orientation of the astronomer.
Quasars have a wide range of appearances when seen by astronomers, suggesting high diversity in their centers. Despite this variety quasars also demonstrate a surprising amount of uniformity in their quantifiable physical properties.
Using a sample of over 20,000 quasars from the Sloan Digital Sky Survey, combined with novel statistical tests, the researchers were able to pinpoint a specific property related to the accretion of the hole. The property is dubbed the Eddington ratio, and is supposedly the driving focus behind the main sequence.
The Eddington ratio describes the efficiency of matter that fuels the black hole and the competition between gravitational forces within. The push and pull between gravity and luminosity has been believed to be the primary-driver behind the sequence, and this new study backs up the hypothesis.
The researchers also found the orientation of the astronomer's sight line when looking into the black hole's inner region plays a significant role in the observations of fast-moving gas within, which produce broad emission lines in quasar spectra. This finding could help astronomers improve their measurements of black hole masses for quasars.
"Our findings have profound implications for quasar research. This simple unification scheme presents a pathway to better understand how supermassive black holes accrete matter and interplay with their environments," said Carnegie's Hubble Fellow Yue Shen.
"And better black hole mass measurements will benefit a variety of applications in understanding the cosmic growth of supermassive black holes and their place in galaxy formation," added Luis Ho of the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University.
The findings were published in the Sept. 11 issue of Nature.
