Sample Shapes of Distant Galaxies Identified in Webb’s CEERS Survey (NIRCam Image)

 Sample Shapes of Distant Galaxies Identified in Webb’s CEERS Survey (NIRCam Image)

For more than a century, astronomers have categorized 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 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 team led by Viraj Pandya, a NASA Hubble Fellow at Columbia University in New York, recently analyzed 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.

“Our analysis of Webb’s galaxies was very consistent with galaxies in the Hubble Space Telescope catalog,” Pandya confirmed. “Two sets of data allowed us to fully vet our models as we ran our analysis, and better understand and categorize galaxies that only Webb detected.” 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.

“Webb confirmed what Hubble has long shown us, but in greater detail in infrared light,” Pandya said. “Their combined observations show that in the early universe, many more galaxies appear flat and elongated. This has profound implications, since we usually assume that galaxies like our own Milky Way started out as disks, but that may not be the case.”

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.

See more galaxy samples from Webb’s CEERS Survey and more concretely compare their 3D shapes.



NASA, ESA, CSA, STScI, Steve Finkelstein (UT Austin), Micaela Bagley (UT Austin), Rebecca Larson (UT Austin)

About The Object
Object Name CEERS Survey, Extended Groth Strip
Object Description Deep field survey
R.A. Position 14:19:46
Dec. Position +52:53:37
Constellation Boötes
Dimensions Image is about 4.2 arcminutes across.
About The Data
Data Description This image was created with Webb data from proposal: (S. Finkelstein). Image Processing: Alyssa Pagan (STScI).
Instrument NIRCam
Exposure Dates 20-21 Dec 2022, 24 Dec 2022
Filters F115W, F150W, F200W, F277W, F356W, F444W
About The Image
Color Info These images are a composite of separate exposures acquired by the James Webb Space Telescope using the NIRCam instrument. Several filters were used to sample wide wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are:   Blue: F115W+F150W Green: F200W + F277W Red: F356W + F444W
Compass Image In the far-left column are two galaxies that have been magnified. The top left galaxy appears circular and light pink with a slightly whiter central region, taking up less than one-sixth of the box. The bottom galaxy is elongated, stretching almost from top left to bottom right. It has a white line at the center that has a pink outline that transitions into bluish edges at far left and right. Thin lines from each magnified galaxy point to their appearances in the broader field. The top galaxy appears as a tiny dot at the upper center, and the bottom galaxy toward the left. Thousands of galaxies appear across most of this view, which is set against the black background of space. There are many overlapping objects at various distances. They include large, blue foreground stars, with Webb’s signature eight-pointed diffraction spikes, and white and pink spiral and elliptical galaxies. Numerous tiny red dots appear throughout the scene. This is a portion of a vast survey known in shorthand as CEERS.
About The Object
Object Name A name or catalog number that astronomers use to identify an astronomical object.
Object Description The type of astronomical object.
R.A. Position Right ascension – analogous to longitude – is one component of an object's position.
Dec. Position Declination – analogous to latitude – is one component of an object's position.
Constellation One of 88 recognized regions of the celestial sphere in which the object appears.
Distance The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
Dimensions The physical size of the object or the apparent angle it subtends on the sky.
About The Data
Data Description
  • Proposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
  • Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.
Instrument The science instrument used to produce the data.
Exposure Dates The date(s) that the telescope made its observations and the total exposure time.
Filters The camera filters that were used in the science observations.
About The Image
Image Credit The primary individuals and institutions responsible for the content.
Publication Date The date and time the release content became public.
Color Info A brief description of the methods used to convert telescope data into the color image being presented.
Orientation The rotation of the image on the sky with respect to the north pole of the celestial sphere.