Molecular Gas Flows in Galaxy Clusters

Powerful radio jets fueled by accretion onto supermassive black holes regulate the rate of cooling in their host galaxies and clusters. Molecular gas is thought to close this feedback loop, connecting the cooling of the cluster’s hot atmosphere to accretion onto nuclear black holes. In this talk I will present recent high-resolution ALMA observations of the molecular gas in brightest cluster galaxies. Unlike normal gas-rich galaxies, the molecular gas in brightest cluster galaxies rarely settles into rotationally-supported disks. Instead, 5-20 kpc long molecular filaments weighing over 10^9 solar masses trail bubbles inflated by the radio jets. These filaments have likely condensed in situ from intracluster gas uplifted in the wakes of buoyantly-rising bubbles. Apparently, the mechanism responsible for heating the cluster atmosphere also stimulates the production of cold gas.