Researchers determined a new method of measuring the distance of far-off galaxies.
Using the new method, researchers measure the "physical and angular, or 'apparent', size of a standard ruler in the galaxy," the University of Southampton reported. This technique is very similar to how distant objects are measured on land.
The research team applied this technique to the NGC4151 galaxy, which has been dubbed the "Eye of Sauron" galaxy by astronomers after a character in "The Lord of the Rings."
In the past the galaxy has been estimated at between four and 29 megaparsecs; through this new method the researchers determined the galaxy was exactly 19 megaparsecs away.
"One of the key findings is that the distance determined in this new fashion is quite precise - with only about 10 percent uncertainty. In fact, if the current result for NGC 4151 holds for other objects, it can potentially beat any other current methods to reach the same precision to determine distances for remote galaxies directly based on simple geometrical principles. Moreover, it can be readily used on many more sources than the current most precise method," said Sebastian Hoenig from the University of Southampton.
The researchers used radiation given off by used hot dust that gathered around the sueprmassive black hole at the center of the galaxy as their "ruler." They determined the physical size of this dust ring by looking at the time delay between the emission of light from near the hole to the infrared emission. The information from the infrared interferometry combined with the W. M. Keck Observatory's twin 10-meter telescopes allowed the team to measure the distance of the galaxy.
"Such distances are key in pinning down the cosmological parameters that [characterize] our universe or for accurately measuring black hole masses. Indeed, NGC 4151 is a crucial anchor to calibrate various techniques to estimate black hole masses. Our new distance implies that these masses may have been systematically underestimated by 40 percent," Hoenig said.
