Madrid, 17 (Europe Press)
In fact, two spiral galaxies in the process of merging, Arp 220 shines most brightly in infrared light, making it an ideal target for Webb. It is an ultra-bright infrared galaxy (ULIRG) with a luminosity of more than a trillion suns.
By comparison, our Milky Way galaxy has a more modest luminosity of about ten billion suns, according to NASA.
Located 250 million light-years away in the Serpens constellation, the Serpent, Arp 220 is object number 220 in Halton Arp’s Atlas of Alien Galaxies. It is the closest ULIRG and the brightest of the three galaxy mergers closest to Earth.
The collision of the two spiral galaxies began about 700 million years ago. It caused a massive explosion of star formation. There are about 200 superclusters of stars in a dusty, compact region about 5,000 light-years in diameter (about 5 percent the diameter of the Milky Way). The amount of gas in this small region is equal to all the gas in the entire Milky Way.
Previous radio telescope observations revealed about 100 supernova remnants in a region less than 500 light-years away. NASA’s Hubble Space Telescope has detected the cores of parent galaxies 1,200 light-years apart. Each of the cores contains a rotating ring of star formation that emits dazzling infrared light that is evident in this view of Webb. This dazzling light produces diffraction spikes, a characteristic of exploding stars that dominate this image.
On the outskirts of this merger, Webb reveals faint tidal tails, or material pulled from galaxies by gravity, depicted in blue, evidence of a galactic dance occurring. Organic matter represented as reddish-orange appears in streams and filaments along Arp 220.
Webb saw the Arp 220 with a near infrared camera (NIRCam) and medium infrared instrument (MIRI).