warm-hot intergalactic medium

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• noun astronomy the relatively hot (warmer than warm, but cooler than hot) intergalactic medium found within a filament of galaxies (galaxy filament), wall of galaxies (galaxy wall), sheet of galaxies (galaxy sheet) or galaxy hypercluster (hypercluster, hypercluster of galaxies). This intergalactic gas is cooler than the X-ray emitting multi-million degree intracluster medium, but warmer than cool intergalactic gas clouds and distant intergalactic space gas far from structures.