Jacinta Bowler
Two brilliant galaxies in the process of merging have been captured by the James Webb Space Telescope (JWST), showing a dazzling spectre of infrared light.
The two galaxies – known collectively as Arp 220 – are 250 million light years away from Earth and are in the constellation of Serpens.
Towards the centre of the image you can see a bright light, this is two galactic cores which are each inside a rotating ring. These star-forming rings are what cause the brightness, as star birth is an energetic process.
We know that Arp 220 is brightest in infrared radiation, which is one of James Webb Space Telescopes’ specialities. It used its Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) to view the galaxy collision.
You can see the difference in the new image by looking at the Hubble version below. This shows that most of the light is obscured by dust and gas. In the JWST image the gas is much more defined, and the cores shine through.
Arp 220 might be far away, but it is still the closest ‘Ultraluminous Infrared Galaxy’ that we know of. It’s also the brightest of the three galactic mergers closest to Earth.
The collision of the two galaxies started about 700 million years ago.
This sparked an enormous burst of star formation, and now there are about 200 huge star clusters in a small area only 5,000 light-years across. To put this in perspective that’s about 5 percent of the Milky Way’s diameter.
The amount of gas in this tiny region is equal to all of the gas in the entire Milky Way galaxy.
Arp 220 has been in the news before. Back in 2011 scientists discovered a record seven supernova inside a single galaxy.
You can download a high quality version of the JWST Arp 220 image here.