Astronomers have discovered a large reservoir of hot gas in the Spiderweb galaxy, the most distant detection of such hot gas yet, using the Atacama Large Millimeter/submillimeter Array (ALMA), of which ESO is a partner. The discovery was published in Nature and further reveals just how early galaxy clusters begin to form. Galaxy clusters host a large number of galaxies and contain a vast “intracluster medium” (ICM) of gas that permeates the space between the galaxies in the cluster. The ICM had only been studied in fully-formed nearby galaxy clusters, so detecting the ICM in distant protoclusters would allow astronomers to catch these clusters in the early stages of formation.
