Chandra X-ray Images of Abell 2390 & MS2137.3-2353
Chandra’s large scale X-ray images show hot gas filling the two giant galaxy clusters, The Chandra data provides a detailed temperature map for the hot gas and allows astronomers to precisely determine the total masses of the clusters. Most of the mass is in the form of dark matter.
(Credit: NASA/IOTA/S.Allen et al.)

Hubble Optical Images of Abell 2390 & MS2137.3-2353
Hubble’s optical images show the distribution of galaxies in the central regions of the same clusters. The Hubble data place independent constraints on the masses of the clusters that confirm the Chandra results.
(Credit: NASA/STScI)

Chandra X-ray Image with Scale Bar
Credit: X-ray: NASA/IOTA/S.Allen et al. Optical: HST