An unprecedented, detailed image of the Milky Way’s centre has mapped a vast, turbulent web of cold gas around the galaxy’s supermassive black hole, with ANU researchers helping decode how stars form in the extreme environment.

An image capturing the central 650 light-years of the Milky Way in extraordinary detail has given astronomers their clearest view yet of the dense, chaotic heart of our galaxy.

Produced using the Atacama Large Millimeter/submillimeter Array (ALMA) in northern Chile, the mosaic is the largest image ever created by the observatory. 

It reveals an intricate network of cold molecular gas filaments surrounding the Milky Way’s supermassive black hole within a region known as the Central Molecular Zone (CMZ).

The international effort – involving more than 160 scientists from more than 70 institutions – includes researchers from The Australian National University, where Professor Christoph Federrath is helping analyse the extreme turbulence shaping star formation near the Galactic Centre.

“The gas that ACES is targeting is cold molecular gas – the raw fuel from which stars form and that ultimately powers them,” Prof Federrath said.

The dataset, produced by the ALMA CMZ Exploration Survey (ACES), shows structures on every scale, from vast gas formations stretching tens of light-years to compact clouds clustered around individual newborn stars. In the sky, the completed image spans a length equivalent to three full moons placed side by side.

Prof Federrath said turbulence is a defining characteristic of star-forming regions, but near the Galactic Centre it becomes far more intense.

“A defining feature of all star-forming clouds is their highly turbulent, chaotic flows of gas and dust,” he said. “Near the Galactic Centre, this turbulence becomes extreme, weaving a dense, tangled web of filaments that ultimately collapse to form new stars.”

Despite its importance, the origin of this turbulence remains one of astrophysics’ biggest open questions. Prof Federrath’s group at ANU is investigating its driving forces by combining supercomputer simulations with the new ACES observations.

“By combining cutting-edge supercomputer simulations with observational datasets like ACES, we can finally begin to unravel the mysteries of the extreme, chaotic conditions under which stars are born,” he said.