James Webb Space Telescope Discovery

Webb Shows Many Early Galaxies Looked Like Pool Noodles, Surfboards

For more than a century, astronomers have categorised galaxies near and far, both by comparing their shapes by eye and precisely measuring their properties with data known as spectra. For example, Edwin Hubble created the Hubble Tuning Fork in 1926 to begin to sort the shapes and sizes of nearby galaxies, showing that many are spirals and ellipticals. As telescopes’ instruments have become increasingly more sensitive, it is easier to more accurately classify their shapes. New data from the NASA/ESA/CSA James Webb Space Telescope have added nuances to astronomers’ classifications. Since Webb observes in infrared light, many more extremely distant galaxies appear in its images. Plus, the images are finely detailed, allowing researchers to identify if there are additional areas of star formation – or confirm they aren’t present. A science team has recently analysed hundreds of distant galaxies in Webb’s Cosmic Evolution Early Release Science (CEERS) Survey. CEERS intentionally covers much of the same area as the Hubble Space Telescope’s Extended Groth Strip, which was one of the five fields used to create the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). This allowed them to double-check Webb’s results where the telescopes’ observations overlap. The analysis of Webb’s galaxies was very consistent with galaxies in the Hubble Space Telescope catalogue. The team began their analysis by sorting the galaxies into broad classes based on similar characteristics. (They did not classify each galaxy’s individual appearance since that would require detailed information from data known as spectra.) They found an array of odd shapes when the Universe was 600 million to 6 billion years old. The galaxy shapes that dominate look flat and elongated, like pool noodles or surfboards. These two galaxy types make up approximately 50 to 80% of all the distant galaxies they studied – a surprise, since these shapes are rare closer to home. Other galaxies Webb detected appear round but also flattened, like frisbees. The least populated category is made up of galaxies that are shaped like spheres or volleyballs. Webb’s data also resolved a riddle that was introduced by the Hubble Space Telescope’s observations decades ago. Why do so many distant galaxies appear like long lines? Was there more to the galaxies that didn’t appear in its images? Webb answered this in short order: Hubble hasn’t missed anything. Why do galaxies have such different shapes early in the history of the Universe? This question remains unanswered for now, but research is underway to better understand how galaxies evolved over all of cosmic time. Credit: ESA, NASA, CSA, STScI, S. Finkelstein (UT Austin), M. Bagley (UT Austin), R. Larson (UT Austin) Sample shapes of distant galaxies identified in Webb’s CEERS survey (NIRCam image)
Portion of Cosmic Evolution Early Release Science (CEERS) survey (NIRCam compass image)
These are examples of distant galaxies captured by the NASA/ESA/CSA James Webb Space Telescope in its Cosmic Evolution Early Release Science (CEERS) Survey. Recent research of the CEERS field showed that galaxies frequently appear flat and elongated, like pool noodles or surfboards (along the top row). Thin, circular disk-like galaxies, which resemble frisbees, are the next major grouping (bottom left and centre). Finally, galaxies that are shaped like spheres, or volleyballs, made up the smallest fraction of their detections (bottom right). All of these galaxies are estimated to have existed when the Universe was 600 million to 6 billion years old. These results are still considered preliminary, because the team sorted images of galaxies into broad classes based on similar characteristics. (They did not classify their individual appearances since that would require detailed information from data known as spectra.) Much more analysis of many more distant galaxies is needed to fully determine which galaxy shapes and compositions existed in the early Universe. 3D classifications for distant galaxies in Webb’s CEERS Survey (NIRCam image)
The NASA/ESA/CSA James Webb Space Telescope is already helping researchers fine-tune their classifications of distant galaxies – adding significant speed and detail to analysis that has been underway for decades. New research has focused on several thousand galaxies in Webb’s Cosmic Evolution Early Release Science (CEERS) Survey that existed when the Universe was 600 million to 6 billion years old. The team found that most distant galaxies do not look like the more familiar spiral and elliptical galaxies that lie closer to Earth. The science team pinpointed four main classifications, shown illustrated above as both 3D objects and cross sections. They are ordered from least to most frequent. At top left, Webb’s survey shows a classification that’s rare in the early Universe, but common today: Galaxies that are shaped like spheres or volleyball. At top right are flattened circular disks or frisbees, which are only slightly more common. The galaxy shapes that dominate during this early period look flat and elongated, like surfboards, shown at bottom left, or pool noodles, bottom right. This pair of classifications make up approximately 50 to 80% of all distant galaxies they’ve studied so far – a surprise, since these shapes are uncommon nearby. The advances in astronomers’ classifications are owed to Webb’s sensitivity, high-resolution images, and specialisation in infrared light. The astronomical community will also need to fully classify more distant galaxies with much larger sample sizes from Webb and other telescopes before settling on any firm groupings. Credit: NASA, ESA, CSA, STScI, J. Olmsted (STScI), V. Pandya (Columbia University), H. Zhang (University of Arizona), L. Reading-Ikkanda (Simons Foundation) 3D classifications for distant galaxies in Webb’s CEERS Survey (NIRCam image)