NASA and the Webb Space Telescope team unveiled a new image from the James Webb Space Telescope this week, and unsurprisingly, it’s amazing. The image shows the Cartwheel Galaxy and its companion galaxies. It’s a composite made using images from Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI).
The Cartwheel Galaxy, also known as ESO 350-40 or PGC 2248, is a rare ring galaxy located about 500 million light-years away in the Sculptor constellation. The Cartwheel Galaxy, seen largest in the image below, resulted from an intense high-speed collision between a large spiral galaxy and a smaller galaxy that’s not visible. The Webb team writes, ‘Collisions of galactic proportions cause a cascade of different, smaller events between the galaxies involved; the Cartwheel is no exception.’
The Cartwheel Galaxy. Credit: NASA, ESA, CSA, and STScI. Click to see the full-resolution image.
The high-speed collision affected the galaxy’s shape and structure. You can see two rings, a bright inner ring, and a surrounding ring. The pair of rings expand outwards from the center of the collision. These features are why astronomers call the Cartwheel Galaxy and other galaxies like it ‘ring’ galaxies.
The bright core of the Cartwheel Galaxy contains a lot of extremely hot dust and the brightest areas are home to large clusters of young stars. The outer ring, which has expanded for about 440 million years, hosts star formation and supernovas. As the ring continues to expand, it interacts with the surrounding gas, triggering additional star formation.
The Hubble Space Telescope has also observed the Cartwheel Galaxy, although its imaging technology couldn’t see as well through the large amount of dust. Webb’s better abilities for detecting infrared light unveil new details about the galaxy.
The Cartwheel Galaxy as seen by Hubble. Credit: ESA/Hubble & NASA. Click to see the full-resolution image.
With Webb’s NIRCam, the space telescope’s primary imaging instrument, scientists can see in the near-infrared range from 0.6 to 5 microns. This allows researchers to see crucial wavelengths of light and observe additional stars. By using infrared light, Webb can see through the dust in the outer ring of the Cartwheel Galaxy and see many of the young stars forming near its outer edge. The Webb team writes, ‘NIRCam also reveals the difference between the smooth distribution or shape of the older star populations and dense dust in the core compared to the clumpy shapes associated with the younger star populations outside of it.’
To learn more about the dust within the galaxy, MIRI reveals regions within the Cartwheel Galaxy that are ‘rich in hydrocarbons and other chemical compounds, as well as silicate dust, like much of the dust on Earth. These regions form a series of spiraling spokes that essentially form the galaxy’s skeleton.’
Cartwheel Galaxy as seen by only NIRCam. Credit: NASA, ESA, CSA, and STScI. Click to see the full-resolution image.
NASA and its Webb partners also released an image using only the data from NIRCam, which looks more like the original Hubble image, albeit with much less detail, and highlights the importance that MIRI plays in the final composite image.