An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has witnessed a cosmic weather event that has never been seen before – a cluster of towering intergalactic gas clouds raining in on the supermassive black hole at the center of a huge galaxy one billion light-years from Earth. The results will appear in the journal Nature on June 9, 2016. 

The cosmic weather report, as illustrated in this artist concept, calls for condensing clouds of cold molecular gas around the Abell 2597 Brightest Cluster Galaxy. The clouds condense out of the hot, ionized gas that suffuses the space between the galaxies in this cluster. New ALMA data show that these clouds are raining in on the galaxy, plunging toward the supermassive black hole at its center. Credit: NRAO/AUI/NSF; Dana Berry / SkyWorks; ALMA (ESO/NAOJ/NRAO) 

  The new ALMA observation is the first direct evidence that cold dense clouds can coalesce out of hot intergalactic gas and plunge into the heart of a galaxy to feed its central supermassive black hole. It also reshapes astronomers’ views on how supermassive black holes feed, in a process known as accretion. 

  Previously, astronomers believed that, in the largest galaxies, supermassive black holes fed on a slow and steady diet of hot ionized gas from the galaxy’s halo. The new ALMA observation shows that, when the intergalactic weather conditions are right, black holes can also gorge on a clumpy, chaotic downpour of giant clouds of very cold molecular gas. 

  For more information about this study, visit: 

  http://www.almaobservatory.org/en/press-room/press-releases/963-alma-witness-intergalactic-deluge-feeding-a-black-hole