Galaxy Cluster A521 (IMAGE) Naval Research Laboratory Caption Superimposed false-color images of the galaxy cluster A521. The blue color represents hot gas typical of many galaxy clusters detected by the Chandra X-ray Observatory. The shape of the X-ray emission indicates that the cluster has undergone a recent collision or "merger event" that could generate turbulent waves. The red represents radio emission at 125 cm wavelength. The bright radio source on the lower left periphery of the X-ray gas is a separate source. The region of radio emission generated by turbulent waves is located at the center of the cluster, where the colors overlap. Credit Radio (NCRA/GMRT/INAF/G.Brunetti et al.); X-ray (NASA/CXC/INAF/S.Giacintucci et al.) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.