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The Webb Space Telescope is ringing in the New Year just like us humans by capturing images of bright bursts of color in the sky. Well, not “in the sky” – Webb itself is a million miles from Earth, and its targets are still a long way off. But a state-of-the-art space observatory recently imaged two large-scale spiral galaxies, and one appears to be the most distant yet identified.
Researchers have written papers on two large spiral galaxies currently hosted on the arXiv print server. One of the ancient galaxies is called A2744-GDSp-z4; the other – even further away – is called Zhúlóng, after the red dragon god in Chinese mythology. Both spiral galaxies are newly discovered and exist spectacularly designed spiral galaxiesa type of spiral galaxy with very well-defined arms. Spiral galaxies with less defined arms are called flocculent spiral galaxies. For reference, our Milky Way is a barred spiral galaxyalthough researchers continue to investigate its exact structure and which label best suits him.
A2744-GDSp-z4 (sorry, no fun nickname) can be seen in Webb’s composite images below. The galaxy weighs about 14 billion solar masses and has a surprisingly advanced structure for its age. The presence of the galaxy indicates that well-defined spiral galaxies existed 1.5 billion years after the Big Bang, that is, at the beginning of the existence of the universe. Although the spiral arms aren’t exactly obvious to the eye, you can make out the general shape, especially in the far left image. The galaxy was found in the Abell 2744 galaxy cluster, one of the Webb galaxies. earliest scientific targets and it had worked before similarly distant galaxies.
Zhúlóng, pictured in pink at the top of this article, is “the most distant bulge+disc galaxy with spiral arms known to date,” according to the paper. It has a mass similar to that of the Milky Way (higher than average for such an early galaxy) and a relatively low star formation rate. A large design spiral produces a total of 66 solar masses per year. This finding is interesting when combined with previous data from the Webb telescope is shown ancient galaxies were metal-poor and very gaseous. Perhaps Zhúlóng, despite its size, did not have the right assets for faster star formation.
Spectacularly designed spirals are pretty far away, which is why they look so pixelated in Webb’s images. One reason Webb can see objects so far away is because it uses it gravitational lenses— are regions of spacetime with such strong gravity that they bend light, allowing us to see objects behind them. When light is bent, it is refocused—magnified—for telescopes like Webb.
In other words, even though giant galaxies look like blobs, the images are amazing and the Webb is working perfectly normally. Closer galaxies seen through a telescope appear in sharper relief. Below is a slider showing how Webb’s instruments revealed different aspects of the spectacularly designed spiral galaxy. The image on the left was taken by Webb’s Near Infrared Camera, or NIRCam, and the image on the right was taken by MIRI, the telescope’s mid-infrared imager. NIRCam captures the warmer light from newly formed stars, while MIRI captures light from the galaxy’s cooler dust and gas grains. The galaxy shown here is sharper than the ancient galaxies discussed in this article because it is closer, only 27 million light-years away.
Webb, an achievement made possible by the telescope’s remarkable insight, continues to shake up our understanding of the early universe versus galactic evolution. Webb can see through giant gas clouds that obscure the faintest and most distant light, allowing researchers to image objects in the early universe. For the past two years, Webb has galaxies depicted formed only a few hundred million years ago After the Big Bang and raised new questions about how these structures unfolded in deep time.
