The image above from the Hubble Space Telescope CANDELS survey, highlights the most distant galaxy in the universe with a measured distance, dubbed z8_GND_5296. The most distant spectroscopically confirmed galaxy ever found — one created at about 700 million years after the Big Bang — has been detected by astronomers at Texas A&M University and the University of Texas at Austin.
The researchers suspect they may have zeroed in on the era when the universe made its transition from an opaque state in which most of the hydrogen is neutral to a translucent state in which most of the hydrogen is ionized. So it’s not necessarily that the distant galaxies aren’t there. It could be that they’re hidden from detection behind a wall of neutral hydrogen fog, which blocks the hydrogen emission signal.
The astronomers note that this is one of two major changes in the fundamental essence of the universe since its beginning — the other being a transition from a plasma state to a neutral state. He is leading the effort on a follow-up paper that will use a sophisticated statistical analysis to explore that transition further.
“Everything seems to have changed since then,” said Vithal Tilvi, a Texas A&M postdoctoral research associate and co-author of the paper now available online.“If it was neutral everywhere today, the night sky that we see wouldn’t be as beautiful. What I’m working on is studying exactly why and exactly where this happened. Was this transition sudden, or was it gradual?”
Our home galaxy, the Milky Way, creates about one or two Sun-like stars every year or so. But this newly discovered galaxy forms around 300 a year. It was observed by the researchers as it was 13 billion years ago. Because the universe has been expanding the whole time, the researchers estimate the galaxy’s present distance to be roughly 30 billion light years away. The detected emission line at a wavelength of 1.0343 micrometres is likely to be Lyman α emission, placing this galaxy at a redshift z = 7.51, an epoch 700 million years after the Big Bang.