(ORDO NEWS) — The light that has traveled over 13.4 billion years to reach our outer space has been confirmed to come from the earliest and most distant galaxy ever discovered.
This places the most distant of these four very young objects at the very dawn of the universe, just a short time after the Big Bang, a time when the universe was still foggy and murky, and the first rays of light penetrated the darkness.
Long JWST spectroscopic observations are detailed in this way, allowing researchers not only to measure the distance traveled by the light of these galaxies, but also to draw a conclusion about some properties of galaxies.
“For the first time, we discovered galaxies just 350 million years after the Big Bang, and we can be absolutely sure of their fantastic distances,” says astronomer Brant Robertson of the University of California at Santa Cruz.
“To find these early galaxies in such stunningly beautiful images is a special experience.”
The ability to see into the universe earlier than we have ever seen before was one of the biggest hopes for JWST.
Our understanding of the first billion years after the Big Bang is extremely limited, and the discovery of earlier objects could help shed light on this crucial formational period.
We have models that describe how events unfolded. We believe that before the birth of the first stars, the Universe was filled with opaque matter; any light was scattered by free electrons and could not flow freely.
These particles gradually combined to form neutral hydrogen; when the stars began to form, they ionized the hydrogen, and light began to shine. This process ended about 1 billion years after the creation of the universe.
The light from these objects is very weak, traveled from very far. And because of the expansion of the universe, it has stretched considerably into the longer, redder end of the spectrum, a phenomenon known as redshift.
JWST is the most powerful telescope ever launched into space, and it specializes in infrared and near-infrared light, designed to detect this redshifted light to the best of our ability.
To obtain a reliable redshift, light must be broken down into its component wavelengths. This method is known as spectroscopy.
The research team split the light from the NIRCam JWST camera into nine wavelength ranges, focusing on four high-redshift galaxies, two of which were first identified by Hubble.
New JWST data confirms that these two galaxies are indeed among the most distant galaxies ever discovered, with the other two even further away.
“It was important to prove that these galaxies do inhabit the early universe. Nearby galaxies may well masquerade as very distant galaxies,” says astronomer Emma Curtis. Lake of the University of Hertfordshire in the UK.
“We saw that the spectrum opened up as we hoped, confirming that these galaxies are at the true edge of our field of view, some farther than Hubble could see! This is an extremely exciting achievement for the mission.”
The two Hubble galaxies have redshifts of 10.38 and 11.58. The new JWST discoveries have redshifts of 12.63 and 13.20, the latter of which is equivalent to about 13.5 billion light-years.
Other candidates for higher redshifts are currently being researched but not yet confirmed. With JWST still out of business for another six months, it probably won’t be long before the record is broken.
But in the meantime, there is work to be done. The observations that these distant galaxies gave us as part of the JWST Extended Deep Extragalactic Survey (JADES) collected a total of 28 hours of data from a region of space in and around the famous Hubble Ultra Deep Field.
This light can tell us a lot about conditions in the early universe and how the first stars and galaxies formed.
“Through these measurements, we can learn the intrinsic brightness of galaxies and figure out how many stars they have,” says Robertson.
“Now we can start to analyze how galaxies come together over time.”
The researchers will present their findings at the First Science Results of JWST STScI. conference. Two preprints can be read here and here.
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