With each passing day, the James Webb Space Telescope (JWST) peers deeper into the universe and further into the past. Its latest discovery is a galaxy named JADES-GS-z14-10. Dating just 300 million years after the Big Bang, it’s the oldest galaxy ever observed. The discovery, along with another nearly equally distant galaxy named JADES-GS-z14-11, were announced in the news this week. paper The study was conducted by an interdisciplinary team led by Stefano Carniani of the École Normale Supérieure in Pisa, Italy.
Astronomers calculate the distance of celestial objects like JADES-GS-z14-10 by looking at what’s called the redshift value. Because the universe is expanding, the wavelength of light waves is stretched as they travel through space. This phenomenon is known as redshift, because it moves light into the infrared region of the electromagnetic spectrum.
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The more distant a source is, the longer it has to travel to reach Earth, and the more redshifted it becomes along the way. JWST’s instruments are designed to observe dramatically redshifted light from distant galaxies, and their sensitivity to this light has led them to break record after record as the most distant objects ever observed. (JADES-GS-z14-10 holds the new record, with a redshift value of 14.32.)
But even objects as distant as JADES-GS-z14-10 pose a challenge for JWST: their light is so faint that it’s often hard to get enough information about them to draw definitive conclusions about their properties. JADES-GS-z14-10 first caught astronomers’ attention because it seemed to buck this trend: Despite its extreme redshift, the galaxy was unusually luminous.
This brightness was initially thought to be due to its proximity on the sky to another nearby galaxy. However, it soon became clear that JADES-GS-z14-10 was special, and its astonishing brightness was unique. This made it a good candidate for a more detailed study, and last October, JWST’s near-infrared camera was trained on the galaxy for five days. The data obtained from these detailed observations allowed scientists to carry out a detailed study of the galaxy. Spectral signatureThis allows us to study the composition and evolution of galaxies in detail, with the results being Attachment.
The paper suggests that JADES-GS-z14-10 “harbors a star with 500 million solar masses that has undergone intense star formation over the last few million years,” much earlier than pre-JWST models thought possible. Carniani says:“It’s amazing that the universe could form such a galaxy in just 300 million years.”
The JWST has delivered one amazing discovery after another like this, revolutionizing our understanding of how and when the first galaxies formed from the primordial gas ejected in the Big Bang. Third paper The paper, published this week, focuses on broader observations of the JADES Origins Field, the region of sky that includes JADES-GS-z14-10, and states that “in the first 18 months of JWST operations, our reach into the cosmic past has been extended by 40%.”
The existence of luminous galaxies like JADES-GS-z14-10 in the early universe has proved to be yet another surprise for scientists: Their incredible brightness makes them and similar objects promising targets for future observations, as they offer tantalizing prospects for peering into what Carniani et al. call “the dawn of the universe…the time when the first galaxies were born.”
