Astronomers, using the Hubble Space Telescope, announced that they have observed and confirmed the most distant galaxies ever detected by pushing Hubble to its limits.
The international team has shattered the cosmic distance record by measuring the farthest galaxies ever see in the universe. This surprisingly bright infant galaxies, named GN-z11, is seen as it was 13.4 billion years in the past — just four hundred million years after the Big Bang.
Now, this galaxy is located in the direction of the constellation Ursa Major and with this observation astronomers are closing in on the first galaxies that formed in the universe and take astronomers into a realm that was once thought to be only reachable by NASA’s upcoming James Webb Space Telescope (JWST).
We’ve taken a major step back in time, beyond what we’d ever expected to be able to do with Hubble,
Pascal Oesch, who is the principal researcher, said.
We see GN-z11 at a time when the universe was only three percent of its current age.
This measure provides strong evidence that some unusual and unexpectedly bright galaxies found earlier in Hubble’ images are really at extraordinary distances. Previously, the team had estimated GN-z11′ distance by determining its color through imaging with Hubble and the Spitzer Space Telescope — this method of using filters to estimate distances is called photometric redshift. But now, for the first time for galaxy at such an extreme distance, the team used Hubble’s Wide Field Camera 3, also called WFC3, to precisely measure the distance to GN-z11′ spectroscopically by splitting the light into its component colors.
This spectroscopic redshift is a much more accurate and definitive measurements for determining distance. The problem is it requires more light to make and these very distant galaxies are barely within Hubble’s vision. But GM-z11 is unusually bright for a galaxy so far away and so the WFC3 spectrograph was able to make the measurement.
And for those who don’t know, astronomers measured large distances by determining the redshift of the objects. This redshift phenomenon is a direct result of the expansion of the universe. Every distant object in the universe appears to be going away from us because it’s light is stretched to longer and redder wavelengths as it travels through time and space to reach our telescopes. The greater the redshift, the farther away the object is.
Astronomers say after looking at this galaxy again and getting the spectroscopic observations, that the galaxy is even further away than they originally thought. It’s right at the distance limit of what Hubble can observe. In the past, using the photometric redshift observations, astronomers determine the distance of GN-z11 as it had a redshift of about 8.68, which puts it about 13.2 billion years in the past. But now with the spectroscopic observations, the team has confirmed that it’s actually has a redshift of 11.1 — nearly 200 million years closer to the time of the Big Bang and that shatters the previous record holders.
The previous record-holder was seen in the middle of the epoch when starlight from primordial galaxies was beginning to heat and lift a fog of cold, hydrogen gas,
said Rychard Bouwens ~ a co-author on the new paper.
This transitional period is known as the re-ionisation era. GN-z11 is observed 150 million years earlier, near the very beginning of this transition in the evolution of the Universe.
So what’s the galaxy like and why is it so bright? Well, these observations show of a very young and hot galaxy creating stars at a huge rate.
It’s amazing that a galaxy so massive existed only 200 million to 300 million years after the very first stars started to form,
said Garth Illingworth ~ coauthor on the new research paper… will be published in the Astrophysical Journal.
It takes really fast growth, producing stars at a huge rate, to have formed a galaxy that is a billion solar masses so soon.
The combination of Hubble and Spitzer imaging, reveals that the GM-z11 is 25 times smaller than the Milky Way and has just one percent of our galaxy’s mass in stars. But this newborn galaxy is also growing very fast and it’s forming stars in a raid about 20 times greater than our galaxy does today.
This star-formation rate allows those extremely remote galaxies to be bright enough for astronomers to find and perform these detailed observations with both Hubble and Spitzer. It’s kind of unexpected thing to see from a such distant galaxy and these results reveal surprising new clues about the nature of the very early universe.
It was surprising to see that a galaxy so massive existed only 200 to 300 million years at such an early point in the universe’s history.
The discovery of GN-z11 showed us that our knowledge about the early universe is still very restricted,
said Ivo Labbe.
How GN-z11 was created remains somewhat of a mystery for now. Probably we are seeing the first generations of stars forming around black holes.
Now, astronomers are saying that these findings provide a preview of the observations that the James Webb Space Telescope will perform after it is launched in 2018. So Hubble and Spitzer are already reaching into the Webb territory and this new discovery shows the JWST will almost certainly find many such young galaxies reaching back to in first galaxies that were forming.