Evidence for invisible matter between galaxies in clusters (intracluster matter)is provided by
A)The rotation curves of clusters that are flatter than Keplerian
B)Absorption lines in the spectra of cluster members
C)Star formation regions between galaxies in clusters
D)X-ray emission from a halo of gas centered on the cluster

Question

Quizplus · Accepted Answer

X-ray emission from a halo of gas centered on the cluster is the best evidence for the existence of intracluster matter. This gas is believed to be made up of hot, ionized plasma and is undetectable by other means, but emits X-rays.

Evidence for Invisible Matter Between Galaxies in Clusters (Intracluster Matter)is