Astronomers Identify Farthest Galaxy in Universe, Determined to be 13.2 Billion Years Old
ByA team of astronomers at the California Institute of Technology (Caltech) detailed the farthest galaxy ever spotted in the universe in a new study.
Their work published in The Astrophysical Journal Letters, the researchers determined the galaxy named EGS8p7 is at least 13.2 billion years old, making it about five hundred million years younger than the universe itself.
"If you look at the galaxies in the early universe, there is a lot of neutral hydrogen that is not transparent to this emission," study co-author Adi Zitrin, a NASA Hubble postdoctoral scholar in astronomy at Caltech, said in a press release. "We expect that most of the radiation from this galaxy would be absorbed by the hydrogen in the intervening space. Yet still we see Lyman-alpha from this galaxy."
Richard Ellis, a recent Caltech retiree and a current professor of astrophysics at University College, London, collaborated on the study.
"The surprising aspect about the present discovery is that we have detected this Lyman-alpha line in an apparently faint galaxy at a redshift of 8.68, corresponding to a time when the universe should be full of absorbing hydrogen clouds," Ellis said in the release.
The researchers are trying to determine how galaxy EGS8p7 is so luminous when it apparently formed in a time when light was hard to come by in the universe.
"Evidence from several observations indicate that the reionization process probably is patchy," Zitrin said. "Some objects are so bright that they form a bubble of ionized hydrogen. But the process is not coherent in all directions.
"We are currently calculating more thoroughly the exact chances of finding this galaxy and seeing this emission from it, and to understand whether we need to revise the timeline of the reionization, which is one of the major key questions to answer in our understanding of the evolution of the universe."