Abell 520 have shown that the behavior of dark matter may not be so naive. Original observations found that the kernel was a banker in dark matter and hot gas, but did not contain luminous galaxies, which normally would be in the same position as the dark matter. The X-ray Observatory NASA's Chandra detected the hot gas. Astronomers used the telescope Canada-France-Hawaii and Subaru, on the summit of Mauna Kea,
