Early galaxy shapes detected by Webb (artist concept)
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.
[Image description: Illustrations of distant galaxy shapes appear in quadrants. Within each quadrant, there are two labels at top left, and two galaxy illustrations, a full 3D object at left and a cross section at right. From top left to bottom right: spheroid or volleyball; oblate or frisbee or; oval or surfboard; and prolate or pool noodle.]
Credit:NASA, ESA, CSA, STScI, J. Olmsted (STScI), V. Pandya (Columbia University), H. Zhang (University of Arizona), L. Reading-Ikkanda (Simons Foundation)