The optical image that confirmed that 2XMM J083026+524133 is a distant cluster of galaxies, taken by the Large Binocular Telescope in Arizona. The X-ray emission from the cluster of galaxies is shown in blue at the centre of the image. The individual galaxies in the cluster are the small dots inside the blue glow. Credit: ESA XMM-Newton/EPIC, LBT/LBC, AIP (J. Kohnert)
