Chandra Release - April 28, 2016

Visual Description: Probing Dark Energy with Clusters

A multipanel shows four galaxy clusters in a two by two grid. Each image depicts a bright purple galaxy cluster that stands out against the dark backdrop of space. Each cluster appears to have a distinct spherical but irregular shape, with some appearing more circular and others more elongated. Tiny individual galaxies within each cluster can also be seen in white and gold, adding to the overall complexity of the images. These galaxy clusters resemble large, colorful balloons floating in the sky. These four galaxy clusters are, from left to right and then top to bottom, are Abell 1835, MS 1455.0+2232, RXJ 1347.5-1145 and ZWCL 3146. They were part of a large survey of over 300 clusters used to investigate dark energy, the mysterious energy that is currently driving the accelerating expansion of the Universe. In these composite images, X-rays from NASA's Chandra X-ray Observatory (colored in purple) have been combined with optical light from the Hubble Space Telescope and Sloan Digital Sky Survey (red, green, and blue).