Knowra Arp 220 Arp 220 Arp 220 is an ultraluminous infrared galaxy about 250 million light-years from Earth. It is the remnant of a merger between two galaxies, with intense star formation and activity around its central black holes.
Galaxy merger : A collision and gravitational interaction between galaxies that can reshape their structure and trigger bursts of star formation. The collision of two galaxies built Arp 220’s disturbed structure and concentrated its gas.
Arp 220 nuclei : The two compact, dusty central regions of Arp 220, interpreted as the surviving nuclei of its progenitor galaxies. Their close separation preserves evidence that Arp 220 formed through a two-galaxy merger.
Infrared astronomy : The study of celestial objects through infrared radiation, which can pass through dust and trace cool material. Infrared observations reveal Arp 220’s enormous luminosity despite its obscuring dust.
Galaxy evolution : The changes in galaxies’ structure, contents, and activity over cosmic time. Arp 220 captures a short-lived transformation from interacting galaxies toward a settled remnant.
Ultraluminous infrared galaxy : A galaxy whose infrared luminosity exceeds one trillion times the Sun’s luminosity. Arp 220 is the nearest prominent example of this class, whose output is largely reprocessed starlight.
Arp 220 superwind : A large-scale outflow of gas from Arp 220, driven by energy from its central starburst and stellar explosions. The outflow shows how Arp 220’s concentrated activity affects gas far beyond its nuclei.
Interstellar dust : Tiny solid particles between stars that absorb and scatter light, then emit energy chiefly at infrared wavelengths. Dust hides Arp 220’s central regions in visible light and reradiates their energy in the infrared.
Star formation feedback : The effects of radiation, winds, and stellar explosions on the gas that forms stars. Arp 220’s starburst and superwind illustrate feedback operating in an exceptionally dense environment.
Starburst galaxy : A galaxy forming stars at a rate far above that typical of galaxies of similar mass. Arp 220’s merger-fed gas supports an unusually intense episode of star formation.
Arp 220 outflow : Gas flowing outward from Arp 220’s central regions, including material traced by molecular and atomic emission. Observations of this outflow reveal how the merger expels gas from the galaxy’s core.
Show all 21