First images from James Webb Space Telescope reveal details never seen before
On July 12, we finally had the grand reveal of the first public images of JWST. After many years in the making, we patiently waited for this moment. We had a perfect launch, a perfect deployment of the telescope’s complicated mechanisms, and a timely march through each one of the commissioning steps to focus the mirror and check all the instruments. Before starting with science observations, the last step was to demonstrate that the telescope met its science objectives – and it did.
The first image revealed is also the first deep field of JWST. In this image, we see several lensed galaxies that appear as arches of light surrounding the center of the image. These are galaxies behind this cluster of galaxies and probably much more distant, but they are revealed to us by the bending of light due to the great mass of the galaxies in the center of this cluster. Although this observation took only 12 hours of observation, it already reveals thousands of galaxies far away, reaching a time when the universe was about 700 million years old. There is no doubt that in the near future and with other scientific observations, we will reach further; to the end of the dark ages and when the first stars formed.
The southern ring nebula has been observed with many telescopes, but none shows the intricate structures of the dust arising from the material that the central star expelled at some point in its life. These golden layers tell the story of how the star shed large amounts of material before becoming a white dwarf, which is only revealed when we observe the nebula in the mid-infrared light.
A less striking and probably difficult to understand is the spectra of the atmosphere of the giant exoplanet WASP-96 b. All the dots and lines in a graph might seem uninteresting; however, once we understand the information those reveal, our curiosity about planets around other stars might increase. This planet was previously observed with Hubble, already revealing the existence of water vapor in its atmosphere. However, with just a few observations, JWST confirms, with exquisite detail and precision, three water vapor features along with other features never seen before that could be indicative of clouds in its atmosphere. With this precision, JWST should be able to observe planets in other systems, including small rocky planets. These and other observations will prove how the atmosphere of planets orbiting other stars compares with the planets in our solar system.
Stephan’s Quintet is a beautiful sample of galaxies of different types and at various stages of life. It also depicts how galaxies merge to form larger and more massive galaxies, which might be nothing like these were before. In the images taken by JWST, we see impressive details not observed before – and much more. In the leftmost galaxy, which is closer to us not part of the cluster, JWST resolves many old stars in its disk. On the right, the mid-infrared observations reveal with great detail fringes of molecular gas that is in between the interacting galaxies and were the shocked gas seems to be triggering some star formation. Plumes of dust can also be seen in the Syfert galaxy at the top right of this image.
And if you look at this image in more detail, you will also see thousands of galaxies in the background -a deep field in itself. This type of background will likely be quite common in most JWST observations.
My favorite image, probably because I am so interested in star formation, is the “Cosmic Cliffs” in the carina. This image shows the edge of a region of star formation. The blue background reveals young stars that, with their intense light, are breaking the molecules in the cloud, heating and ionizing the freed atoms that escape the molecular region in ghostly plumes of gas. At the bottom, we have molecular gas. Although dusty clouds, opaque in the visible light, become transparent in the infrared, in this image we still see a fine blanket of gas obscuring the stars in the background. The reason is that the molecular gas is still somewhat opaque in the infrared, with the dark and opaque regions still forming stars. The mid-infrared observations reveal some of these young objects, some of which are still surrounded by their cocoons or have disks that make them look fuzzy and red.
The five images unveiled about six and a half months after the launch of JWST demonstrate that it can indeed achieve the science for which it was developed. These observations also give us a clear idea of what JWST will be able to do. The images are just a tease, a taste of what will be coming in the next few months, once the scientists start making observations.