A large pink, speckled, wheel-like galaxy with a small inner oval, with dusty blue between them to the right, with two smaller spiral galaxies of roughly the same size to the left against a black background. This image of the Cartwheel and its companion galaxies is a composite of the Webb Near Infrared Camera (NIRCam) and the Mid-Infrared Instrument (MIRI), revealing details that are difficult to see in individual images alone. Courtesy: NASA, ESA, CSA, STScI
Webb’s instruments are revealing new details about star formation
The incredible imaging capabilities of NASA’s James Webb Space Telescope have revealed the Pinwheel Galaxy, a rare ring galaxy once shrouded in dust and mystery.
Formed as a result of a collision between a large spiral galaxy and another smaller galaxy, the galaxy not only retained much of its spiral character, but also underwent massive changes in its structure.
Webb’s high-precision instruments recognize individual stars and star-forming regions in Cartheel. They also revealed the behavior of the black hole at its galactic center. These new details provide a renewed understanding of a galaxy in the midst of a slow transformation.
This image from the Webb Mid-Infrared Instrument (MIRI) shows a cluster of galaxies, including a large distorted ring galaxy known as the Wheel. The Cartwheel Galaxy, located 500 million light-years away in the constellation Sculptor, is composed of a bright inner ring and an active outer ring. While this outer ring has a lot of star formation, the dusty zone between them reveals many stars and star clusters. The mid-infrared light captured by MIRI reveals fine details about these dusty regions and young stars in the Wheel galaxy, which are rich in hydrocarbons and other chemical compounds, as well as silicate dust, like much of the dust on Earth. Courtesy: NASA, ESA, CSA, STScI, Webb ERO Production Team
Webb captures stellar gymnastics in the Cartheel galaxy
Peering into the chaos of the Wheel galaxy, NASA’s James Webb Space Telescope is revealing new details about star formation and the galaxy’s central black hole. Webb’s powerful infrared vision produced this detailed image of the Cartwheel and two smaller satellite galaxies against a backdrop of many other galaxies. This new view reveals how the Wheel Galaxy has changed over billions of years.
Located about 500 million light-years away in the constellation Sculptor, the Cartwheel galaxy is a rare sight. Its appearance, like a wagon wheel, is the result of an intense event – a high-speed collision between a large spiral galaxy and a smaller galaxy not visible in this image. Galactic-sized collisions cause a cascade of different, smaller events between the galaxies involved, and the Cartwheel is no exception.
The collision mostly affected the shape and structure of the galaxy. The Colello galaxy has two rings – a bright inner ring and a surrounding, colorful ring. These two rings expand outward from the center of the collision, like ripples in a lake after a stone is thrown into it. Because of these distinctive features, astronomers call this a “ring galaxy,” a structure less common than spiral galaxies like our Milky Way.
The bright core contains a huge amount of hot dust, with the brightest regions home to giant young star clusters. On the other hand, the outer ring, which has been expanding for about 440 million years, is dominated by star formation and supernovae. As this ring expands, it penetrates the surrounding gas and triggers star formation.
Other telescopes, including the Hubble Space Telescope, have already studied the Wheel. But the dramatic galaxy is shrouded in mystery—perhaps literally, given the amount of dust that obscures the view. Webb, with his ability to detect infrared light, is now revealing new insights into the nature of the Wheel.
The Near Infrared Camera (NIRCam), Webb’s primary imager, looks in the near-infrared range from 0.6 to 5 microns, seeing crucial wavelengths of light that can reveal even more stars than are seen in visible light. This is because young stars, many of which form in the outer ring, are less obscured by the presence of dust when viewed in infrared light. In this image, the NIRCam data are colored blue, orange and yellow. The galaxy shows many individual blue dots, which are individual stars or pockets of star formation. NIRCam also reveals the difference between the smooth distribution, or shape, of the populations of older stars and dense dust in the core compared to the clumpy shapes associated with the populations of younger stars outside.
This is an image of the Cartwheel Galaxy taken with the NASA/ESA (European Space Agency) Hubble Space Telescope. Credit: ESA/Hubble & NASA
Learning finer details about the dust that inhabits the galaxy, however, requires the Webb Mid-Infrared Instrument (MIRI). MIRI data is colored red in this composite image. It reveals regions in the Wheel Galaxy 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 spiral spokes that essentially form the skeleton of the galaxy. These spokes were evident in previous Hubble observations published in 2018, but they become much more prominent in this Webb image.
Webb’s observations highlight that Cartwheel is in a very transitional stage. The galaxy, which was probably a normal spiral galaxy like the Milky Way before its collision, will continue to transform. While Webb gives us a snapshot of the current state of the Wheel, he also gives insight into what has happened to this galaxy in the past and how it will evolve in the future.
The James Webb Space Telescope is the world’s leading space science observatory. Webb will solve mysteries in our solar system, look beyond distant worlds around other stars, and explore the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners ESA (European Space Agency) and the Canadian Space Agency.
Add Comment