ARP 220

Alt. Designations: ARP 220, IC 1127
Object Type: spiral galaxy
Constellation: Serpens
Distance: 250 mly
Right Ascension: 15h 34m 57.2s
Declination: +23° 30´ 09"
Visual Magnitude: 13.4
Apparent Dimension: 1.8´ x 1.7´
Best Month To View: Jun

Arp 220 Appears to be a single, odd-looking galaxy, but is in fact a nearby example of the aftermath of a collision Between Two spiral galaxies. It is the brightest of the three galactic mergers closest to Earth, about 250 million light-years away in the constellation Serpens of, the Serpent. The collision, Which Began about 700 million years ago, has sparked a cracking burst of star formation, Resulting in about 200 huge star clusters in a packed, dusty region of about 5.000 light-years across (about 5 percent of the Milky Way's diameter). The amount of gas in this tiny region equals the amount of gas in the entire Milky Way Galaxy. The star clusters are the bright bluish-white knots visible in the Hubble image. Arp 220 glows brightest in infrared light and is an ultra-luminous infrared galaxy. Previous Hubble Observations, taken in the infrared at a wavelength that looks through the dust, have uncovered the cores of the parent galaxies 1.200 light-years apart. Observations with NASA's Chandra X-ray Observatory have also revealed X-rays coming from both cores, Indicating the presence of two Supermassive Black Holes. Arp 220 is the 220th galaxy in Arp's Atlas of Peculiar Galaxies.