Astronomers delve into heart of supermassive black hole using ALMA observatory

Researchers, using the Atacama Large Millimeter/submillimeter Array (ALMA), have delved into the heart of an active galactic nucleus (AGNs) at the center of the Circinus Galaxy, paving the way for a more holistic grasp of the growth dynamics of supermassive black holes.

Led by Assistant Professor Takuma Izumi from the National Astronomical Observatory of Japan (NAOJ), the international team have highlighted the intricate dance of gas flows around the galaxy's supermassive black hole. They have elucidated the accretion flow that feeds the monster black hole.

According to the observations, a significant fraction is ejected as atomic or molecular outflows, which eventually return back and are again drawn towards the black hole in a cyclical pattern, akin to a water fountain.

This is the first time that researchers have quantitatively measured gas flows and their structures for all phases - plasma, atomic, and molecular - at a tiny spatial scale of just a few light-years around a supermassive black hole.

The achieved resolution was approximately one light-year - the highest resolution achieved for multiphase gas observations in an AGN.

An AGN is a small region at the heart of active galaxies that is far brighter than the combined light of the galaxy's stellar population. AGNs appear so bright that they can outshine the rest of the galaxy.

AGNs are powered by accretion onto supermassive black holes in galaxies. It is worth noting that a portion of the gas that falls towards the black hole (accretion flow) is thought to be blown away by the immense energy of this AGN, leading to outflows.

"Detecting accretion flows and outflows in a region just a few light-years around the actively growing supermassive black hole, particularly in a multiphase gas, and even deciphering the accretion mechanism itself, are indeed monumental achievements in the history of supermassive black hole research," said Takuma Izumi.