Using two instruments aboard the NASA/ESA/CSA James Webb Space Telescope, astronomers have produced detailed images of the Cartwheel Galaxy and its two smaller companions.
This image of the Cartwheel Galaxy and its companion galaxies is a composite from Webb’s NIRCam and MIRI instrument. Image credit: NASA / ESA / CSA / STScI / Webb ERO Production Team.
The Cartwheel Galaxy is a lenticular galaxy located 500 million light-years away in the constellation of Sculptor.
Otherwise known as ESO 350-40, IRAS 00352-3359 or LEDA 2248, it has a diameter of 150,000 light-years and a mass of about 3 billion solar masses.
Along with the two companion galaxies, the Cartwheel is part of a small group of galaxies.
“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,” Webb astronomers said.
“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,” they noted.
“The 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,” they said.
“On the other hand, the outer ring, which has expanded for about 440 million years, is dominated by star formation and supernovae.”
“As this ring expands, it plows into surrounding gas and triggers star formation.”
The astronomers observed the Cartwheel using Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI).
“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,” they explained.
“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.”
This image from Webb’s MIRI instrument shows a group of galaxies, including a large distorted ring-shaped galaxy known as the Cartwheel Galaxy. Image credit: NASA / ESA / CSA / STScI / Webb ERO Production Team.
“Learning finer details about the dust that inhabits the galaxy, however, requires the MIRI instrument,” they added.
“MIRI data are colored red in the 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 researchers said.
“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.”
source: https://www.sci.news
