NASA’s James Webb Space Telescope has peered into the chaos of the
Cartwheel Galaxy, revealing new details about star formation and the galaxy’s
central black hole. Webb’s powerful infrared gaze produced this detailed image
of the Cartwheel and two smaller companion galaxies against a backdrop of many
other galaxies. This image provides a new view of how the Cartwheel Galaxy has
changed over billions of years.
The Cartwheel Galaxy, located about 500 million light-years away in the
Sculptor constellation, is a rare sight. Its appearance, much like that of the
wheel of a wagon, 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.
Collisions of galactic proportions cause a cascade of different, smaller events
between the galaxies involved; the Cartwheel is no exception.
The collision most notably affected the galaxy’s shape and structure. The
Cartwheel Galaxy sports two rings — a bright inner ring and a surrounding,
colorful ring. These two rings expand outwards from the center of the
collision, like ripples in a pond after a stone is tossed 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 tremendous amount of hot dust with the brightest
areas being the home to gigantic young star clusters. On the other hand, the
outer ring, which has expanded for about 440 million years, is dominated by
star formation and supernovas. As this ring expands, it plows into surrounding
gas and triggers star formation.
Other telescopes, including the Hubble Space Telescope, have previously
examined the Cartwheel. But the dramatic galaxy has been shrouded in mystery –
perhaps literally, given the amount of dust that obscures the view. Webb, with
its ability to detect infrared light, now uncovers new insights into the nature
of the Cartwheel.
This image from Webb’s Mid-Infrared Instrument (MIRI) shows a group of
galaxies, including a large distorted ring-shaped galaxy known as the
Cartwheel. The Cartwheel Galaxy, located 500 million light-years away in the
Sculptor constellation, is composed of a bright inner ring and an active outer
ring. While this outer ring has a lot of star formation, the dusty area in
between reveals many stars and star clusters. Credits: NASA, ESA, CSA,
STScI, Webb ERO Production Team Download the
full-resolution, uncompressed version and supporting visuals from the Space
Telescope Science Institute
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 observed in visible light. This is because young stars, many of
which are forming in the outer ring, are less obscured by the presence of dust
when observed in infrared light. In this image, NIRCam data are
colored blue, orange, and yellow. The galaxy displays 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 older
star populations and dense dust in the core compared to the clumpy shapes
associated with the younger star populations outside of it.
Learning finer details about the dust that inhabits the galaxy, however,
requires Webb’s Mid-Infrared
Instrument (MIRI). MIRI data are
colored red in this composite image. It reveals regions within the Cartwheel
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 spiraling
spokes that essentially form the galaxy’s skeleton. These spokes are evident
in previous Hubble
observations released in 2018, but they become
much more prominent in this Webb image.
Webb’s observations underscore that the Cartwheel is in a very transitory
stage. The galaxy, which was presumably 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 Cartwheel, it also provides insight into
what happened to this galaxy in the past and how it will evolve in the future.
The James Webb Space Telescope is the world's premier
space science observatory. Webb will solve mysteries in our solar system, look
beyond to distant worlds around other stars, and probe 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.
Source: Webb
Captures Stellar Gymnastics in The Cartwheel Galaxy | NASA
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