Hot Atmospheres and Molecular Clouds in Galaxy Clusters

The Atacama Large Millimeter Array has sharpened our understanding of molecular clouds in central cluster galaxies. Unlike spiral galaxies where molecular clouds lie primarily in disks traveling in ordered motion about the center of the galaxy, molecular clouds in cluster central galaxies lie primarily in blobs and filaments outside of the nucleus. Chandra X-ray imaging suggest that at least some molecular clouds form in the updrafts of radio bubbles rising through hot atmospheres. This mechanism may drive these systems to a self-regulating feedback state. Gas condensing from hot atmospheres may be quickly transformed into molecular clouds by high atmospheric pressure.