The James Webb Space Telescope has captured this beautiful image of a dramatic cosmic event: two galaxies colliding. Two spiral galaxies are in the process of merging, and are shining brightly in the infrared wavelengths where James Webb operates, shining with the light of more than a trillion suns.
It’s not uncommon for two (or more) galaxies to collide and merge, but the two galaxies pictured here emit very bright infrared light. The pair has the combined name, Arp 220, because they appear as single objects when viewed from Earth. Known as an ultraluminous infrared galaxy (ULIRG), Arp 220 shines much brighter than ordinary spiral galaxies like the Milky Way.
Reported from Digital Trends, Arp 220 is 250 million light years away, but its bright beam allowed Webb to capture the object using the Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI). By combing through the data from these two instruments, scientists can see the object in the near-infrared and mid-infrared.
While the process of galactic collisions can be destructive, they can also create lots of new stars — as happened in this case. “The collision of two spiral galaxies began about 700 million years ago,” said the Webb scientists. “That triggers a huge burst of star formation. About 200 large star clusters reside in a dense, dusty region about 5,000 light years (about 5% of the Milky Way’s diameter). The amount of gas in this tiny region is equal to all the gas in the entire Milky Way galaxy.”
Arp 220 was previously imaged by the Hubble Space Telescope in 2008. Comparing the two images not only shows the difference when observing at different wavelengths, as Hubble sees the visible part of the spectrum compared to Webb’s infrared, but also shows how much more detail is visible thanks to technological advances over the last 15 years.
