The Webb telescope detects an ancient galaxy built like the Milky Way
The Webb Space Telescope’s latest target is one previously imaged by Hubble: the distant barred spiral galaxy EGS23205. Goals like this will improve our understanding of the early universe and how ancient stars and galaxies formed.
The two images above show EGS23205 as seen by Hubble and Webb. The Hubble image of the galaxy (taken in the near-infrared) is much noisier and the structure of the galaxy is harder to discern. But the Webb image (at mid-infrared wavelengths) is much sharper, revealing a clear bar of stars extending from the galactic center.
Stellar bars are huge galactic cross-sections composed of countless stars. Bars play an important role in galactic evolution; they push gas toward the galactic center, helping to fuel star formation and fuel the supermassive black holes found inside galactic nuclei. Our own Milky Way is a barred spiral galaxy.
The image analysis was presented on the arXiv preprint server last year. Webb has imaged many ancient galaxies in its six months of science operations.
Some of Webb’s goals are among the first galaxies seen so farand they look to Webb as they were only a few hundred million years after the Big Bang (the universe is now about 14 billion years old).
EGS23205 looks like it did about 11 billion years ago. The image reveals that even the earliest galaxies had well-defined bars (spiral galaxies were previously thought to be much later arrivals in the universe).
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“The nearly visible bars in the Hubble data have just come out in the JWST image, showing the enormous power of JWST to see the structure underlying galaxiesShardha Jogee, an astronomer at UT Austin and co-author of the research, said in a Press release.
Webb has already imaged other objects once captured by Hubble. In Octoberthe new $10 billion observatory looked at the pillars of creation, huge plumes of gas and dust in the Eagle Nebula. The same month, Webb’s team produced an image of merged galaxies 270 million light years from Earth, photographed by Hubble in 2008.
The two space telescopes observe at different wavelengths for the most part: Hubble primarily at visible wavelengths and Webb primarily in the infrared and near-infrared. Webb’s vivid work is built on Hubble’s mechanical shoulders. Side by side image comparisons show the differences between these impressive observatories and what is possible with newer technology.
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