Astrophysicists detect most luminous diffuse gamma-ray emission from Arp 220

A University of Oklahoma team has detected for the first time the most luminous gamma-ray emission from a galaxy--the merging galaxy Arp 220 is the nearest ultraluminous infrared galaxy to Earth, and it reveals the hidden extreme energetic processes in galaxies. The first gamma-ray detection of an ultraluminous infrafred galaxy occurs when the most energetic cosmic rays collide with the interstellar medium causing these galaxies to glow--expanding observations of these galaxies to the highest en...