Most accurate distance ever measured for an unimaginably distant and small primordial Galaxy in the early Universe
By combining several redundant methods, scientists are able to measure with unprecedented level of accuracy the distance of a Galaxy located at redshift 10, that's about 13.3 billion light years in the past when the Universe was only about 500 million years old.
"Using the NASA/ESA Hubble Space Telescope astronomers have made what may be the most reliable distance measurement yet of an object that existed in the Universe's formative years. The galaxy is one of the faintest, smallest and most distant galaxies ever seen and measuring its distance with this accuracy was possible due only to the incredibly detailed mapping of how giant galaxy clusters warp the space-time around them.
Astronomers often use gravitational lensing—the magnifying power of galaxy clusters—to find distant galaxies. However, when it comes to the very early Universe, distance measurements can become inaccurate as the objects are so dim. Now, a team of astronomers has combined a traditional method of distance measurement with some clever reverse engineering to vastly improve accuracy.
The lensing power of the mammoth galaxy cluster Abell 2744, nicknamed Pandora's Cluster, focussed the light from the faraway galaxy that was being studied, making it appear about ten times brighter than it otherwise would have been, and allowing astronomers to see it. The lensing also produced three magnified images of the same galaxy.
The team's results appeared in the online edition of Astrophysical Journal Letters on 4 September 2014."