Uncovered Possibly, the Most Remote Distinct Spiral Galaxy with Clear Structure, Ever Detected by Human Observers
Uncovered Possibly, the Most Remote Distinct Spiral Galaxy with Clear Structure, Ever Detected by Human Observers
The James Webb Space Telescope is ringing in the New Year similarly to us humans, capturing vivid splashes of color in the cosmic landscape. However, it's not in our sky; rather, it's a million miles away from Earth, peering into galaxies that are even further. The advanced space observatory has recently snapped images of two sprawling spiral galaxies, with one being the most distantly recognized yet.
Scientific papers about these two colossal spiral galaxies have surfaced on the preprint server arXiv. One of the galaxies, dating back ages, is called A2744-GDSp-z4; the other, even more antiquated, bears the name Zhúlóng, a reference to a Chinese mythological red dragon. Both galaxies are newly discovered and fall under the category of grand design spiral galaxies, characterized by their well-defined arms. Compared to grand design spiral galaxies, galaxies with less defined arms are grouped under the category of flocculent spiral galaxies. Our Milky Way, for instance, is a barred spiral galaxy, although researchers are still debating its exact structure and categorization.
A2744-GDSp-z4, devoid of a catchy nickname, can be observed in the composite images below, courtesy of Webb. Its estimated mass stands at around 14 billion solar masses and has a striking level of structure for its age. The galaxy's existence indicates that spiral galaxies with distinct, well-articulated designs existed as early as a billion and a half years after the Big Bang. Though the spiral arms might not be discernible to the naked eye, the general shape is evident, particularly in the leftmost image. The galaxy was discovered within the galaxy cluster Abell 2744, one of Webb's initial scientific targets, which has previously unveiled similarly distant galaxies.
Composite images of A2744-GDSp-z4, snapped by Webb across various color bands. Image credit: Jain et al., 2024
Zhúlóng, depicted at the top of this article in pink, is "the most distant bulge+disk galaxy with spiral arms discovered to date," as described in the article. It has a mass similar to that of the Milky Way and boasts a relatively low star formation rate. The grand design spiral galaxy is only generating around 66 solar masses per year. This fact is intriguing given that previous Webb telescope data suggested ancient galaxies were primarily metal-poor and highly gaseous. Perhaps, Zhúlóng, despite its size, lacked the necessary components for a more rapid rate of star formation.
The remarkable grand design spirals, situated a considerable distance away, appear pixelated in the Webb images. The telescope's ability to capture such distant objects is partially due to the use of gravitational lenses—regions of space-time with incredibly strong gravitational forces that bend light, enabling us to glimpse objects behind them. The light bends and focuses, magnifying the images for telescopes like Webb, allowing for a closer look at distant galaxies.
In conclusion, although the distant galaxies appear blurry, the images are awe-inspiring, with Webb operating perfectly well within its capabilities. Nearby galaxies, imaged by the telescope, stand out in sharper relief. Below is a slider demonstrating how Webb's instruments bring to light various facets of a grand design spiral galaxy. The left image was captured by Webb's Near-Infrared Camera, while the right image was produced by MIRI, the telescope's mid-infrared imager. The Near-Infrared Camera picks up heat emitted by newly formed stars, while MIRI captures the galaxy's light from cold grains of dust and gas. The galaxy shown here is far more detailed than the ancient galaxies mentioned in this article, as it is located closer, at approximately 27 million light-years away.
The James Webb Space Telescope continues to revolutionize our understanding of the early universe by shedding light on galactic evolution. This breakthrough has been made possible by the telescope's unparalleled vision, allowing researchers to observe objects from the early universe that were previously hidden behind thick gas clouds. Over the past two years, Webb has imaged galaxies that formed just a few hundred million years after the Big Bang, raising new questions about their formation and evolution over time.
The discovery of A2744-GDSp-z4 and Zhúlong in the distant cosmic landscape suggests that advanced technology and future space missions, powered by cutting-edge science, will lead to the unveiling of even more grand design spiral galaxies tucked away in the farthest corners of space. The future of space exploration holds promise for identifying and studying these ancient galaxies, offering insights into the early universe and the evolution of galaxies over time.
As we continue to analyze the data gathered from the James Webb Space Telescope, we can anticipate that future advancements in technology and scientific research will allow us to perceive these distant galaxies with increasing clarity and detail, unlocking new secrets about the universe and its development.