Chandra Release - October 15, 2008

Visual Description: Abell 521

A composite image of galaxy cluster Abell 521 is shown, which features a blue and pink-orange shape in the center of the image. The shape is like a bat with only one wing, and it is surrounded by a few blue points of light. The Chandra X-ray Observatory data, in blue, shows hot gas in the cluster, and an image from the Giant Meterwave Radio Telescope in India shows radio emission in pink-orange. The elongated shape of the blue X-ray emission shows that the cluster has undergone a violent collision, where another group or cluster of galaxies collided with the main cluster. The radio image shows a bright band of radio emission on the lower left portion of the X-ray gas, which is a separate source. The radio emission in the center of the cluster is bright at the relatively long wavelength of 125 cm (as shown), but is much fainter at shorter wavelengths. This variation in behavior agrees with theoretical predictions for acceleration of particles by turbulent waves generated by a violent collision.