Astronomers have discovered a supermassive black hole about to devour clouds of cold, clumpy gas.
Until now, scientists believed supermassive black holes in the largest galaxies fed on a slow, steady diet of hot, ionized gas from the galaxy’s halo.
“Although it has been a major theoretical prediction in recent years, this is one of the first unambiguous pieces of observational evidence for a chaotic, cold ‘rain’ feeding a supermassive black hole,” says Grant Tremblay, an astronomer at Yale University and lead author of a new study published in the journal Nature.
“It’s exciting to think we might actually be observing this galaxy-spanning ‘rainstorm’ feeding a black hole whose mass is about 300 million times that of our sun.”
The discovery offers new insight into the way black holes ingest fuel, a process called accretion. The most common way for black holes to feed is by taking in hot, ionized gas that spirals in slowly from a surrounding disc of cosmic material.
For the study, researchers analyzed data from the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile to map the locations and movement of cold molecular gas in the Abell 2597 Cluster—a knot of about 50 galaxies located 1 billion light years from Earth.
They detected a trio of cold gas clouds, traveling as fast as a million kilometers per hour, heading toward a black hole in a galaxy at the center of the cluster. Each gas cloud contained as much material as a million suns and measured tens of light-years across.
“We can’t know whether all or only part of this ‘meal’ of cold gas will ultimately fall into the black hole, but the ALMA data spectacularly highlights the importance of this kind of cold accretion,” says coauthor C. Megan Urry, professor of physics and astronomy.
“Since we know so little about the mechanics of how the AGN (active galactic nucleus) interacts with the rest of the galaxy, this is a real step forward,” adds coauthor Louise Edwards, an astronomy lecturer and researcher.
Researchers next plan to use ALMA to search for similar “rainstorms” in other galaxies to see if this kind of cosmic weather is a common phenomenon.
Researchers from Michigan State University, the University of Michigan, the University of Rochester, Massachusetts Institute of Technology, the Harvard-Smithsonian Center for Astrophysics, the Naval Research Laboratory Remote Sensing Division, and institutions in Germany, the Netherlands, France, Canada, the United Kingdom, and Mexico are coauthors of the work.
Source: Yale University
