Since the James Webb Space Telescope started operating last year, we have received a ton of amazing photographs. Fraser even included a video a few weeks ago that detailed what we discovered as a result. But the story doesn’t stop there; most recently, the Prime Extra-Galactic Areas for Reionization and Lensing Science (PEARLS) team published a quartet of papers outlining Webb’s observations of the galaxy cluster known as El Gordo (literally, “the fat one”), which is a nickname for it in Spanish. But that’s not all; they also unveiled another picture that is simply breathtaking.
It is crucial to first comprehend gravitational lensing in order to completely comprehend the image displayed as the banner, as well as the one that is described in more detail in the link below. The broad idea has been covered extensively before, and we’ve even showed some amazing pictures of things called Einstein rings. The most important concept to grasp is that huge objects, like the El Gordo galaxy cluster, which was formed some 6.8 billion years ago, have the ability to magnify objects that appear in front of them by bending light around their bulk, a process known as “gravitational lensing.”
This is precisely the reason the Webb team focused on this gigantic galaxy cluster, which is believed to be the largest to have existed at that time in the history of the universe. The incredible astronomical photographer Webb’s predecessor, Hubble, also captured some shots of El Gordo, but its sensitivity was insufficient to fully depict the scene’s magnificence.
The fact that astronomers can use those amazing photographs for science is an added benefit. The four papers from the PEARLS team, lead by Brenda Fyre of the University of Arizona, focus on different aspects of the image. Only one of the studies analyzes the overall impact of the gravitational lensing effect provided by El Gordo.
The upper right corner of the image appears to include a galaxy that is bent like a fishhook, earning it the moniker of one of the graduate students on the PEARLS team. This is one of the image’s most prominent aspects. It appears red in Webb’s infrared image, in part because of dust within the galaxy itself but also because of the redshift brought on by light traveling 10.6 billion years to reach Earth.
The size of the Fishhook, a tiny disk galaxy, is only about one-fourth that of the Milky Way. Even more than 10 billion years ago, the star-forming zone in the middle appeared to be withering away, a process known as “quenching” in astronomy. The second publication, directed by Patrick Kamieneski of Arizona State University, focused on that discovery.
The line in the image’s middle left is another element that some viewers might even mistake for an artifact of the imaging process. In actuality, El Gordo is using its lens to focus on a different galaxy that is 11 billion light-years away from Earth. Known as La Flaca, which translates to “the thin one” in Spanish. The galaxy itself is just cool to look at, but a more subtle aspect of the picture fascinates researchers.
A red dwarf star close to La Flaca is the first of its kind to have been seen beyond 1 billion years from Earth. It was only seen because of El Gordo’s gravitational lensing and Webb’s ultrasensitive sensors, and is now known by its Quechua name, Quyllur. Individual stars at a distance usually need to be “blue” to avoid having their light shifted out of the observable spectrum by the redshift that comes with being that far away. However, Quyllur won’t likely be the only object the telescope discovers using Webb’s capabilities. The third paper, written by Jose Diego of the Spanish Institute of Physics in Cantabria, explained its discovery.
Other, less noticeable aspects of the image also pique the curiosity of experts. A pair of “ultra-diffuse” galaxies and a tiny galaxy cluster both date back to the same period (12.1 billion years). These are challenging to picture as a “galaxy” in the traditional sense due to the stars’ great distance from one another. At a previously unheard-of distance of 7.2 billion light years, Webb nevertheless succeeded. According to the fourth research by Timothy Carleton of Arizona State, distant diffuse galaxies even have a different appearance from nearby ones.
Overall, this collection of papers synthesizes a richness of scholarly understanding with the help of one of the most breathtaking astronomical images ever captured. And as Webb enters its second year of existence, more will undoubtedly start arriving.