Thursday, May 7, 2015
Astronomers find most distant galaxy ever
Astronomers have located the most distant galaxy ever measured in the universe, some 13.1 billion light-years from Earth.
The galaxy, called EGS-zs8-1, is one of the brightest and most massive objects in the early universe, the scientists report in the journal Astrophysical Journal Letters.
The finding pushes back the cosmic frontier of galaxy exploration to a time when the universe was only 5 per cent of its present age of 13.8 billion years. The galaxy existed so long ago, it appears to be only 100 million years old.
The team of astronomers from Yale and the University of California, Santa Cruz say that EGS-zs8-1 is still forming stars rapidly, about 80 times faster than our galaxy, the Milky Way, which has a star formation rate of one star per year.
"It has already grown more than 15 per cent of the mass of our own Milky Way today," says Pascal Oesch, lead author of the study from Yale University, New Haven, Connecticut.
"But it had only 670 million years to do so. The universe was still very young then."
Only a handful of galaxies currently have accurate distances measured in this very early universe.
"Every confirmation adds another piece to the puzzle of how the first generations of galaxies formed in the early universe," says study co-author Pieter van Dokkum of Yale.
"Only the most sensitive telescopes are powerful enough to reach to these large distances."
The galaxy was first spotted in images from NASA's Hubble and Spitzer space telescopes.
Calculating its exact distance from Earth was possible using the MOSFIRE instrument on the W.M. Keck Observatory's 10-metre telescope in Hawaii, researchers say.